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Mappings

MONDO

MONDO:0018883 Berardinelli-Seip congenital lipodystrophy

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Inheritance

1

Autosomal recessive inheritance HP:0000007

The congenital generalized presentation is recessive. When both parents carry the relevant pathogenic allele, each pregnancy has a 25% risk of the biallelic condition. Heterozygous PPARG alleles can cause partial lipodystrophy, so carrier counseling is gene- and allele-specific.

Autosomal recessive inheritance

Show evidence (3 references)

ORPHA:528 SUPPORT Other

"Autosomal recessive"

Orphanet records autosomal recessive inheritance.

PMID:11967537 SUPPORT DIRECT Human Clinical

"Congenital generalized lipodystrophy is an autosomal recessive disorder characterized by marked paucity of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset of diabetes."

The AGPAT2 discovery study states the autosomal recessive inheritance pattern.

PMID:20301391 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier."

Historical AGPAT2/BSCL2-focused counseling; asymptomatic-carrier wording is not extended to PPARG.

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Subtypes

5

Type 1 (AGPAT2) MONDO:0012071

AGPAT2 hgnc:325

AGPAT2-related CGL (OMIM 608594) predominantly removes metabolically active adipose depots, including marrow fat, while mechanical fat in palms, soles and orbital regions is relatively preserved. Lytic bone lesions are particularly associated with this subtype.

Show evidence (2 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations."

Disease-specific clinical synthesis.

PMID:11967537 SUPPORT DIRECT Human Clinical

"We report several different mutations of the gene (AGPAT2) encoding 1-acylglycerol-3-phosphate O-acyltransferase 2 in 20 affected individuals from 11 pedigrees of diverse ethnicities showing linkage to chromosome 9q34."

Founding linkage and sequence study.

Type 2 (BSCL2/seipin) MONDO:0010020

BSCL2 hgnc:15832

BSCL2/seipin-related CGL (OMIM 269700) removes both metabolic and mechanical fat. Intellectual impairment is enriched compared with other genotypes; cardiomyopathy can occur across genotypes and was not significantly different between groups in the 70-patient genotype–phenotype study.

Show evidence (2 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations."

Disease-specific clinical synthesis.

PMID:11479539 SUPPORT DIRECT Human Clinical

"Most of the variants are null mutations and probably result in a severe disruption of the protein."

Founding BSCL2 families; not every allele is null.

Type 3 (CAV1) MONDO:0012923

CAV1 hgnc:1527

Biallelic CAV1-related CGL (OMIM 612526) is extremely rare. Mechanical and marrow fat may be preserved. In addition to the original patient, four related patients were reported in 2021, with achalasia in two. Other heterozygous CAV1-associated disorders are distinct.

Show evidence (3 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations."

Disease-specific clinical synthesis.

PMID:18211975 SUPPORT DIRECT Human Clinical

"RESULTS: A homozygous nonsense mutation (p.Glu38X) was identified in CAV1 in a patient with BSCL born from a consanguineous union."

Original homozygous CAV1 nonsense variant; fibroblasts lack both caveolin-1 isoforms.

PMID:34643546 SUPPORT DIRECT Human Clinical

"Four patients, aged 8 months to 18 years, carried a new homozygous p.(His79Glnfs*3) CAV1 variant."

Primary extension of CGL3 beyond the founding case.

Type 4 (CAVIN1/PTRF) MONDO:0013225

CAVIN1 hgnc:9688

Biallelic CAVIN1/PTRF-related CGL (OMIM 613327) combines loss of caveolae with lipodystrophy, myopathy and potentially life-threatening arrhythmia. Fat loss may progress during infancy. Mechanical and marrow fat can be preserved; muscle mounding, pyloric stenosis and atlantoaxial instability are characteristic additional findings.

Show evidence (2 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations."

Disease-specific clinical synthesis.

PMID:20300641 SUPPORT DIRECT Human Clinical

"Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate leading to the detection of homozygous mutations (c.160delG, c.362dupT)."

Primary CAVIN1 families.

PPARG-associated congenital generalized lipodystrophy MONDO:0979300

PPARG hgnc:9236

A rare biallelic PPARG form of congenital generalized lipodystrophy. PPARG encodes the PPARgamma nuclear receptor that drives differentiation of preadipocytes into adipocytes. Monoallelic loss-of-function PPARG variants cause autosomal dominant familial partial lipodystrophy type 3, curated in the Familial Partial Lipodystrophy entry; the rare recessive cases have severe generalized or CGL-like lipoatrophy, with variable chronology and depot preservation. ClinGen therefore curates PPARG-related lipodystrophy as semidominant, and MONDO files this concept as a subclass of Berardinelli-Seip congenital lipodystrophy.

Show evidence (5 references)

PMID:24980513 SUPPORT DIRECT Human Clinical

"The phenotype and presence of two mutations suggests that biallelic mutations at PPARG cause a CGL similar to that observed with biallelic AGPAT2 or BSCL2 mutations."

The report that places biallelic PPARG alongside AGPAT2 and BSCL2 as a cause of congenital generalized lipodystrophy, which is what makes this a subtype row on this entry rather than a separate disease.

PMID:36806620 SUPPORT DIRECT Human Clinical

"They carried monoallelic PPARG variants except a homozygous patient with congenital generalized lipodystrophy."

A second cohort in which the one homozygous patient, unlike the 25 heterozygous patients, had congenital generalized lipodystrophy.

CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z SUPPORT Other

"The occasional recessive cases typically feature early-onset, congenital generalized lipodystrophy, also known as Berardinelli-Seip syndrome, due to biallelic variants in PPARG (PMIDs:24980513, 36806620)."

ClinGen's expert-panel narrative states that the recessive PPARG cases are early-onset congenital generalized lipodystrophy, i.e. this disease.

+ 2 more references

⚙

Pathophysiology

13

AGPAT2 acylglycerol synthesis defect

Loss of AGPAT2 impairs lysophosphatidic-acid acylation in adipocytes. This disrupts normal glycerolipid synthesis and adipogenesis. A global fall in phosphatidic acid is not assumed: compensatory hepatic pathways can increase particular phosphatidic-acid species in knockout mice.

adipocyte CL:0000136

AGPAT2 hgnc:325

triglyceride biosynthetic process GO:0019432 ↓ DECREASED

lysophosphatidic acid acyltransferase activity GO:0042171 ↓ DECREASED

Downstream

Generalized adipose tissue loss Disordered glycerolipid handling compromises adipose development and storage capacity.

Show evidence (1 reference)

PMID:11967537 SUPPORT DIRECT BACKGROUND Human Clinical

"The AGPAT2 enzyme catalyzes the acylation of lysophosphatidic acid to form phosphatidic acid, a key intermediate in the biosynthesis of triacylglycerol and glycerophospholipids."

Biochemical function described as background in the human genetic discovery paper.

BSCL2 seipin lipid-droplet dysregulation

Seipin deficiency disrupts lipid-droplet organization at the endoplasmic reticulum. Cell models also show dysregulated lipolysis, recorded as a separate downstream event.

adipocyte CL:0000136

BSCL2 hgnc:15832

lipid droplet organization GO:0034389 ⚠ ABNORMAL

lipid droplet GO:0005811

Downstream

Unrestrained adipocyte lipolysis Seipin loss permits excessive cAMP/PKA-driven lipolysis in the reported cell models.

Intellectual disability BSCL2-associated disease is enriched for intellectual impairment through an unresolved neurological mechanism.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Seipin has been postulated to have an important role in lipid droplet assembly and in adipocyte differentiation."

Mechanistic synthesis; detailed seipin functions remain model-dependent.

Unrestrained adipocyte lipolysis

Bscl2-deficient mouse-derived cells show excessive cAMP/PKA-dependent lipolysis during differentiation.

Experimental models

Bscl2-deficient adipogenic cultures PRIMARY CELL CULTURE

Downstream

Failure of terminal adipocyte differentiation Excessive lipolysis disrupts completion of adipogenesis in this model.

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT In Vitro

"In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated..."

Knockout mouse-derived cells, not direct patient adipocyte measurements.

Failure of terminal adipocyte differentiation

Early adipogenic differentiation can begin, but Bscl2-deficient cells fail to maintain terminal differentiation and adipocyte-specific transcription.

Experimental models

Bscl2-deficient adipogenic cultures PRIMARY CELL CULTURE

Downstream

Generalized adipose tissue loss Failure to form and maintain mature adipocytes contributes to loss of adipose tissue.

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT In Vitro

"In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated..."

Knockout mouse-derived cells, not direct patient adipocyte measurements.

CAV1-dependent caveola loss

Biallelic CAV1 loss disrupts caveola formation. Patient fibroblasts lack caveolae and caveolar proteins. Adipose storage and insulin-response effects are supported by these patient cells and experimental models; each tissue need not have identical changes. The adipocyte binding identifies the disease-relevant cell type; the directly cited caveola and insulin-response assays were performed in fibroblasts, not patient adipocytes.

adipocyte CL:0000136

CAV1 hgnc:1527

caveola assembly GO:0070836 ↓ DECREASED

Experimental models

CAV1-deficient patient fibroblasts PRIMARY CELL CULTURE

Downstream

Generalized adipose tissue loss CAV1 deficiency compromises adipose maintenance; the complete intervening sequence remains unresolved.

CGL3 achalasia Biallelic CAV1 loss is associated with achalasia through an unresolved esophageal mechanism.

Show evidence (1 reference)

PMID:34643546 SUPPORT DIRECT In Vitro

"Patients' fibroblasts showed a complete loss of caveolae and no protein expression of caveolin-1 and its caveolin-2 and cavin-1 partners. Patients' fibroblasts also displayed insulin resistance, increased oxidative stress, and premature senescence."

Patient fibroblast caveolar phenotype.

CAVIN1 caveola biogenesis defect

CAVIN1 deficiency markedly reduces caveolae in patient fibroblasts and skeletal muscle. Caveolin localization is abnormal; reported abundance differs between studies, with preserved caveolin-1/3 in one cohort and reduced protein in another.

adipocyte CL:0000136

CAVIN1 hgnc:9688

caveola assembly GO:0070836 ↓ DECREASED

Experimental models

CAVIN1-deficient patient fibroblasts PRIMARY CELL CULTURE

Downstream

Generalized adipose tissue loss Loss of caveolae impairs adipose maintenance.

CGL4 congenital myopathy Caveolar disruption is associated with muscle dysfunction; tissue-specific intermediates remain incomplete.

CGL4 cardiac arrhythmia risk Cardiac electrophysiological consequences involve unresolved intermediates.

CGL4 muscle mounding Caveolar disease is associated with this subtype manifestation; detailed tissue-specific intermediates remain unresolved.

CGL4 prolonged QT interval Caveolar disease is associated with this subtype manifestation; detailed tissue-specific intermediates remain unresolved.

CGL4 polymorphic ventricular tachycardia Caveolar disease is associated with this subtype manifestation; detailed tissue-specific intermediates remain unresolved.

CGL4 pyloric stenosis Subtype-associated structural manifestation; the intervening developmental mechanism remains uncertain.

CGL4 atlantoaxial instability Subtype-associated structural manifestation; the intervening developmental mechanism remains uncertain.

Show evidence (2 references)

PMID:20300641 SUPPORT DIRECT In Vitro

"Morphometric analysis by transmission electron microscopy of the quantity of caveolae on the cell surface revealed a severe reduction by >97% in the patient's fibroblasts (Figure 7A and 7B)."

Direct quantification of caveola loss in patient fibroblasts.

PMID:19726876 SUPPORT DIRECT Human Clinical

"Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all 3 caveolin family members, and reduction of caveolae structure."

Human biopsy localization abnormalities.

PPARG adipogenic nuclear receptor deficiency

Reduced PPARgamma transcriptional function compromises adipocyte differentiation. Rare biallelic cases have a severe generalized or CGL-like distribution; heterozygous alleles may themselves cause partial lipodystrophy. The generalized boundary remains qualified by the subtype evidence.

adipocyte CL:0000136

PPARG hgnc:9236

preadipocyte differentiation into adipocytes GO:0045444 ↓ DECREASED

Downstream

Generalized adipose tissue loss Impaired adipogenesis underlies severe fat loss in rare biallelic cases.

Show evidence (3 references)

PMID:39398333 SUPPORT DIRECT BACKGROUND Other

"PPARγ plays an essential role in adipogenesis, stimulating the differentiation of preadipocytes into adipocytes."

The quoted statement describes established receptor biology, not a measurement in the reviewed patients. OTHER with BACKGROUND is appropriate for this gene-level function; the same review is graded HUMAN_CLINICAL with REVIEW_SYNTHESIS when it summarizes the biallelic patient phenotype in the subtype record.

CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z SUPPORT Other

"Both loss of function and dominant negative variants have been reported."

Supports the DECREASED direction on the adipogenic function: the reported variant classes reduce rather than increase PPARgamma activity.

PMID:24980513 SUPPORT DIRECT Human Clinical

"Sequencing PPARG identified two pathogenic mutations; c.413_416delAATG; p.Glu138ValfsX168 and c.490C>T; p.R164W."

The two PPARG variants carried by the index patient, one frameshift and one missense, establishing the biallelic lesion this node starts from.

Generalized adipose tissue loss

Adipose triglyceride storage capacity is profoundly reduced. Metabolic and mechanical depot involvement differs by genotype, and CGL4 fat loss may be progressive in infancy.

adipocyte CL:0000136 ↓ DECREASED

adipose tissue UBERON:0001013

Animal models

Bscl2 knockout mice Mus musculus recapitulates

Downstream

Lipodystrophy Near-total adipose loss clinically manifests as generalized lipodystrophy.

Adipose tissue loss Loss of adipocytes produces the HPO adipose tissue loss phenotype.

Ectopic triglyceride accumulation Inability to store triglyceride in adipose tissue diverts lipid to non-adipose organs.

Prominent superficial veins Near-total subcutaneous adipose loss can make superficial veins conspicuous.

Leptin deficiency Loss of adipose endocrine tissue lowers leptin.

Circulating triglyceride excess Deficient adipose storage contributes to circulating lipid excess.

Show evidence (2 references)

ORPHA:528 SUPPORT Other

"generalized lipoatrophy with acromegaloid features"

Orphanet's definition supports generalized lipoatrophy as a core feature.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Congenital generalized lipodystrophy (CGL) is a heterogeneous autosomal recessive disorder characterized by a near complete lack of adipose tissue from birth and, later in life, the development of metabolic complications, such as diabetes mellitus, hypertriglyceridaemia and hepatic steatosis."

The review describes near-complete adipose tissue absence in CGL.

Leptin deficiency

Markedly reduced adipose mass results in severe hypoleptinemia.

Downstream

Increased appetite Leptin deficiency increases appetite.

Severe insulin resistance Leptin has metabolic actions beyond appetite; their complete cellular route is not resolved.

Low leptin concentration The low serum measurement reflects deficient circulating leptin.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near total loss of fat."

Disease-specific clinical synthesis.

Increased appetite

Loss of leptin satiety signaling increases appetite and food intake.

Downstream

Ectopic triglyceride accumulation Excess intake adds to the lipid load that cannot be stored in adipose depots.

Hyperphagia Increased appetite manifests clinically as hyperphagia.

Accelerated growth High appetite is associated with accelerated childhood growth in the clinical synthesis; endocrine and nutritional intermediates are not fully specified.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Profound hypoleptinaemia in patients with CGL further exacerbates metabolic derangements by inducing hyperphagia."

Disease-specific clinical synthesis.

Ectopic triglyceride accumulation

Inadequate adipose storage favors lipid deposition in liver and other nonadipose tissues. Hepatic lipid burden and insulin resistance are associated, but triglyceride itself is not assumed to be the sole toxic mediator. Muscle lipid excess is not universal across subtypes or samples.

hepatocyte CL:0000182 cell of skeletal muscle CL:0000188

liver UBERON:0002107 skeletal muscle tissue UBERON:0001134

Downstream

Hepatic steatosis Ectopic triglyceride accumulation in hepatocytes produces hepatic steatosis.

Cirrhosis Chronic hepatic lipid injury in congenital generalized lipodystrophy can progress to cirrhosis in a subset of patients.

Hepatomegaly Hepatic lipid accumulation contributes to liver enlargement.

Severe insulin resistance Hepatic steatosis and intramyocellular lipid accumulation contribute to the severe insulin-resistance mechanism, although the intervening molecular steps remain incompletely defined.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The predominant cause of metabolic complications in CGL is excess triglyceride accumulation in the liver and skeletal muscle owing to the inability to store triglycerides in adipose tissue."

The review states the central mechanism for metabolic complications.

Circulating triglyceride excess

Reduced adipose lipid-storage capacity and metabolic dysregulation produce severe hypertriglyceridemia.

Downstream

Hypertriglyceridemia Circulating triglyceride excess is the biochemical phenotype.

Pancreatitis Extreme triglyceride elevation predisposes to pancreatic inflammation.

Eruptive xanthomas Severe lipid excess causes cutaneous lipid deposition.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and adolescence and only rarely during infancy."

Disease-specific clinical synthesis.

Severe insulin resistance

Insulin action is severely impaired. Compensatory hyperinsulinemia may initially preserve glucose tolerance; diabetes develops when compensation is inadequate. Lipid and leptin pathways contribute through incompletely resolved intermediates.

insulin receptor signaling pathway GO:0008286 ↓ DECREASED

Downstream

Insulin resistance The mechanism directly produces the clinical insulin-resistance phenotype.

Hyperinsulinemia Pancreatic compensation for insulin resistance increases circulating insulin.

Diabetes mellitus Severe insulin resistance predisposes to diabetes mellitus.

Acanthosis nigricans Chronic insulin resistance can produce acanthosis nigricans.

Hirsutism Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual mediators are incompletely established.

Clitoromegaly Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual mediators are incompletely established.

Irregular menstruation Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual mediators are incompletely established.

Polycystic ovaries Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual mediators are incompletely established.

Show evidence (2 references)

PMID:11967537 SUPPORT DIRECT Human Clinical

"Congenital generalized lipodystrophy is an autosomal recessive disorder characterized by marked paucity of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset of diabetes."

The AGPAT2 discovery paper includes extreme insulin resistance in the clinical phenotype.

ORPHA:528 SUPPORT Other

"muscle hypertrophy, insulin resistance, hypertriglyceridemia"

Orphanet includes insulin resistance as a defining feature.

✶

Histopathology

2

CGL4 dystrophic muscle and reduced caveolae

Skeletal muscle can show dystrophic changes, abnormal caveolin localization and sparse caveolae. The extent of fibrosis, necrosis and caveolin protein depletion differs between reported cohorts; reduced membrane organization is more consistent than universal loss of caveolin abundance.

Show evidence (2 references)

PMID:19726876 SUPPORT DIRECT Human Clinical

"Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all 3 caveolin family members, and reduction of caveolae structure."

Direct muscle biopsy findings in the Japanese CGL4 cohort.

PMID:20300641 SUPPORT DIRECT Human Clinical

"PTRF-CAVIN protein was completely absent from fibroblasts and skeletal muscle, whereas the caveolin-1 and caveolin-3 abundance was unchanged (Figure 4D and 4G)."

Contrasting protein abundance in a separate primary series.

CGL4 intestinal smooth-muscle hypertrophy

Massive smooth-muscle hypertrophy was demonstrated in a colonic specimen after ileus in one patient; this is not a finding measured in every case.

Show evidence (1 reference)

PMID:20300641 SUPPORT DIRECT Human Clinical

"At 12 years of age, an acute ileus after appendectomy required a partial bowel resection and histology of the colon wall revealed massive smooth muscle hypertrophy."

Patient bowel histology.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

46

Cardiovascular 8

Prominent superficial veins OCCASIONAL HP:0001015

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0001015 | Prominent superficial veins | Occasional (29-5%)"

Orphanet provides the disease-phenotype association and frequency band.

Hypertrophic cardiomyopathy OCCASIONAL HP:0001639

Show evidence (3 references)

ORPHA:528 SUPPORT Other

"HP:0001639 | Hypertrophic cardiomyopathy | Occasional (29-5%)"

Orphanet records hypertrophic cardiomyopathy as occasional.

PMID:12362029 SUPPORT DIRECT Human Clinical

"In all subjects, hepatic dysfunction, hyperlipidaemia, diabetes mellitus, and hypertrophic cardiomyopathy were significant contributors to morbidity with no clear differences in their prevalence between subjects with BSCL1 or BSCL2 and those with evidence against cosegregation with either..."

The genotype-phenotype cohort identifies hypertrophic cardiomyopathy as a morbidity contributor.

PMID:20301391 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hypertrophic cardiomyopathy is reported in 20%-25% of affected individuals and is a significant cause of morbidity from cardiac failure and early mortality."

Historical GeneReviews estimate, not a current subtype-specific risk.

Congestive heart failure OCCASIONAL HP:0001635

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0001635 | Congestive heart failure | Occasional (29-5%)"

Orphanet provides the disease-phenotype association and frequency band.

CGL4 cardiac arrhythmia risk HP:0011675

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"predisposition to serious arrhythmias such as catecholaminergic polymorphic ventricular tachycardia, long QT interval and sudden death"

The CGL review identifies serious arrhythmias and sudden death as CGL4-specific risks.

CGL4 prolonged QT interval HP:0001657

Show evidence (1 reference)

PMID:20300641 SUPPORT DIRECT Human Clinical

"The corrected QT-time was between 430–501 ms (Figure 2E)."

One directly described CGL4 patient.

CGL4 polymorphic ventricular tachycardia HP:0031677

Show evidence (1 reference)

PMID:20684003 SUPPORT DIRECT Human Clinical

"Therefore, an exercise study was conducted which revealed several runs of asymptomatic polymorphic ventricular tachycardia (Fig. 3C)."

Primary exercise-test observation.

Hypertension HP:0000822

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hypertension is common (25), even in children."

Guideline synthesis across lipodystrophy syndromes, supported by subtype case reports.

Splenomegaly HP:0001744

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Prominence of umbilicus or umbilical hernia is often noticed at birth, which is probably due to underlying hepatomegaly and/or splenomegaly."

Disease-specific clinical synthesis.

Digestive 7

Hepatomegaly VERY_FREQUENT HP:0002240

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0002240 | Hepatomegaly | Very frequent (99-80%)"

Orphanet records hepatomegaly as very frequent.

Hepatic steatosis HP:0001397

Show evidence (3 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients can have liver enlargement due to hepatic steatosis in infancy."

Disease-specific clinical synthesis.

PMID:20301391 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hepatomegaly secondary to hepatic steatosis and skeletal muscle hypertrophy occur in all affected individuals."

Historical GeneReviews description of classic BSCL; not an all-subtype prevalence estimate.

PMID:20684003 SUPPORT DIRECT Human Clinical

"Two of them had hepatic steatosis."

Two of five molecularly characterized CGL4 patients; limits extension of the classic universal statement.

Cirrhosis OCCASIONAL HP:0001394

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0001394 | Cirrhosis | Occasional (29-5%)"

Orphanet provides the disease-phenotype association and frequency band.

Pancreatitis HP:0001733

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Severe hypertriglyceridaemia is often associated with eruptive xanthomas and recurrent pancreatitis, particularly in patients with uncontrolled diabetes mellitus."

Disease-specific clinical synthesis.

CGL4 pyloric stenosis HP:0002021

Show evidence (1 reference)

PMID:20684003 SUPPORT DIRECT Human Clinical

"Two patients belonging to CGL178 pedigree required surgery for pyloric stenosis in the first month of life."

Primary CGL4 case series.

CGL3 achalasia HP:0002571

Show evidence (1 reference)

PMID:34643546 SUPPORT DIRECT Human Clinical

"Two patients also presented at the age of 15 and 18 years with dysphagia due to achalasia, and one patient had retinitis pigmentosa."

Primary CGL3 family.

Umbilical hernia HP:0001537

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Prominence of umbilicus or umbilical hernia is often noticed at birth, which is probably due to underlying hepatomegaly and/or splenomegaly."

Disease-specific clinical synthesis.

Endocrine 2

Diabetes mellitus FREQUENT HP:0000819

Show evidence (3 references)

ORPHA:528 SUPPORT Other

"HP:0000819 | Diabetes mellitus | Frequent (79-30%)"

Orphanet records diabetes mellitus as frequent.

PMID:20301391 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Affected individuals develop insulin resistance and approximately 25%-35% develop diabetes mellitus between ages 15 and 20 years."

Historical GeneReviews age-specific estimate.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal years."

Disease-specific clinical synthesis.

Hyperinsulinemia HP:0000842

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal years."

Disease-specific clinical synthesis.

Genitourinary 5

Clitoromegaly Clitoral hypertrophy HP:0008665

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present with primary or secondary amenorrhoea and polycystic ovaries."

Disease-specific clinical synthesis.

Irregular menstruation HP:0000858

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present with primary or secondary amenorrhoea and polycystic ovaries."

Disease-specific clinical synthesis.

Polycystic ovaries HP:0000147

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present with primary or secondary amenorrhoea and polycystic ovaries."

Disease-specific clinical synthesis.

Proteinuria HP:0000093

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Proteinuria is common (34). Kidney biopsy should be performed as clinically indicated, and pathology may include diabetic nephropathy, focal segmental glomerulosclerosis (especially in CGL) (34) or MPGN (especially in APL) (17)."

Guideline synthesis across lipodystrophies; no CGL-specific frequency inferred.

Focal segmental glomerulosclerosis HP:0000097

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Kidney biopsy should be performed as clinically indicated, and pathology may include diabetic nephropathy, focal segmental glomerulosclerosis (especially in CGL) (34) or MPGN (especially in APL) (17)."

Guideline distinguishes CGL-associated FSGS from APL-associated MPGN.

Head and Neck 2

Mandibular prognathia OCCASIONAL HP:0000303

Show evidence (2 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients with type 1 CGL have a characteristic body fat distribution and might present with acromegaloid features with enlarged mandible, hands and feet (Figure 1a)."

Disease-specific clinical synthesis.

ORPHA:528 SUPPORT DIRECT Other

"HP:0000303 | Mandibular prognathia | Occasional (29-5%)"

Orphanet disease-level frequency band.

Macroglossia OCCASIONAL HP:0000158

Show evidence (1 reference)

ORPHA:528 SUPPORT DIRECT Other

"HP:0000158 | Macroglossia | Occasional (29-5%)"

Orphanet disease-level frequency band.

Integument 4

Hypertrichosis FREQUENT HP:0000998

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0000998 | Hypertrichosis | Frequent (79-30%)"

Orphanet records hypertrichosis as frequent.

Acanthosis nigricans HP:0000956

Show evidence (2 references)

ORPHA:528 SUPPORT Other

"HP:0000956 | Acanthosis nigricans | Occasional (29-5%)"

Orphanet records acanthosis nigricans as occasional.

PMID:11479539 SUPPORT DIRECT Human Clinical

"Other clinical and biological features include acanthosis nigricans, hyperandrogenism, muscular hypertrophy, hepatomegaly, altered glucose tolerance or diabetes mellitus, and hypertriglyceridemia."

The BSCL2 discovery paper lists acanthosis nigricans among clinical features.

Eruptive xanthomas Xanthomatosis HP:0000991

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Severe hypertriglyceridaemia is often associated with eruptive xanthomas and recurrent pancreatitis, particularly in patients with uncontrolled diabetes mellitus."

Disease-specific clinical synthesis.

Hirsutism HP:0001007

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present with primary or secondary amenorrhoea and polycystic ovaries."

Disease-specific clinical synthesis.

Limbs 1

Large hands OCCASIONAL HP:0001176

Show evidence (2 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients with type 1 CGL have a characteristic body fat distribution and might present with acromegaloid features with enlarged mandible, hands and feet (Figure 1a)."

Disease-specific clinical synthesis.

ORPHA:528 SUPPORT DIRECT Other

"HP:0001176 | Large hands | Occasional (29-5%)"

Orphanet disease-level frequency band.

Metabolism 5

Insulin resistance VERY_FREQUENT HP:0000855

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0000855 | Insulin resistance | Very frequent (99-80%)"

Orphanet records insulin resistance as very frequent.

Hypertriglyceridemia FREQUENT HP:0002155

Show evidence (2 references)

ORPHA:528 SUPPORT Other

"HP:0002155 | Hypertriglyceridemia | Frequent (79-30%)"

Orphanet records hypertriglyceridemia as frequent.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and adolescence and only rarely during infancy."

Disease-specific clinical synthesis.

Hypercholesterolemia OCCASIONAL HP:0003124

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0003124 | Hypercholesterolemia | Occasional (29-5%)"

Orphanet provides the disease-phenotype association and frequency band.

CGL4 elevated creatine kinase Elevated circulating creatine kinase activity HP:0003236

Show evidence (1 reference)

PMID:19726876 SUPPORT DIRECT Human Clinical

"Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase levels were observed in these patients."

Five patients in a muscular-dystrophy-ascertained series.

Low HDL cholesterol Decreased HDL cholesterol concentration HP:0003233

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"HDL cholesterol levels also tend to be low."

Disease-specific clinical synthesis.

Musculoskeletal 8

Skeletal muscle hypertrophy VERY_FREQUENT HP:0003712

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0003712 | Skeletal muscle hypertrophy | Very frequent (99-80%)"

Orphanet records skeletal muscle hypertrophy as very frequent.

Adipose tissue loss VERY_FREQUENT HP:0008887

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0008887 | Adipose tissue loss | Very frequent (99-80%)"

Orphanet records adipose tissue loss as very frequent.

Lipodystrophy VERY_FREQUENT HP:0009125

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"HP:0009125 | Lipodystrophy | Very frequent (99-80%)"

Orphanet records lipodystrophy as very frequent.

CGL4 congenital myopathy HP:0003198

Show evidence (1 reference)

PMID:20684003 SUPPORT DIRECT Human Clinical

"All patients had near total loss of body fat and congenital myopathy manifesting as weakness, percussion-induced muscle mounding, and high serum creatine kinase levels."

Congenital weakness and other myopathic findings in five patients from three CGL4 pedigrees.

Lytic bone lesions Osteolysis HP:0002797

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"These patients also have increased predisposition to develop lytic lesions in the appendicular skeleton (Table 1)."

AGPAT2 subtype context in the review.

CGL4 atlantoaxial instability HP:0003467

Show evidence (1 reference)

PMID:20684003 SUPPORT DIRECT Human Clinical

"Three of them had atlantoaxial instability. Two patients belonging to CGL178 pedigree required surgery for pyloric stenosis in the first month of life."

Primary CGL4 case series.

CGL4 muscle mounding HP:0003719

Show evidence (1 reference)

PMID:19726876 SUPPORT DIRECT Human Clinical

"Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase levels were observed in these patients."

Primary clinical observations.

Advanced bone age OCCASIONAL Accelerated skeletal maturation HP:0005616

Show evidence (2 references)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Advanced bone age has also been reported in nine individuals."

Disease-specific clinical synthesis.

ORPHA:528 SUPPORT DIRECT Other

"HP:0005616 | Accelerated skeletal maturation | Occasional (29-5%)"

Orphanet disease-level frequency band.

Nervous System 2

Intellectual disability HP:0001249

Show evidence (1 reference)

PMID:12362029 SUPPORT DIRECT Human Clinical

"Notably, subjects with BSCL2 had a significantly higher prevalence of intellectual impairment than those with BSCL1 or BSCLX (p<0.0001, OR 17.0, CI 3.6 to 79.0)."

Human genotype association does not establish a lipid-droplet mechanism for intellectual disability.

Hyperphagia Polyphagia HP:0002591

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Profound hypoleptinaemia in patients with CGL further exacerbates metabolic derangements by inducing hyperphagia."

Disease-specific clinical synthesis.

Growth 2

Proportionate tall stature OCCASIONAL HP:0011407

Show evidence (1 reference)

ORPHA:528 SUPPORT DIRECT Other

"HP:0011407 | Proportionate tall stature | Occasional (29-5%)"

Orphanet disease-level frequency band.

Accelerated growth Overgrowth HP:0001548

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Children with CGL have accelerated growth owing to a voracious appetite."

Disease-specific clinical synthesis.

🧬

Genetic Associations

5

AGPAT2 pathogenic variants (Causative biallelic pathogenic variants)

Gene: AGPAT2 hgnc:325 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (2 references)

PMID:11967537 SUPPORT DIRECT Human Clinical

"We report several different mutations of the gene (AGPAT2) encoding 1-acylglycerol-3-phosphate O-acyltransferase 2 in 20 affected individuals from 11 pedigrees of diverse ethnicities showing linkage to chromosome 9q34."

Founding linkage and sequence study.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"However, the type of mutation does not seem to determine the phenotype or the severity of fat loss."

AGPAT2 genotype–phenotype limitation.

Variants (1)

Biallelic AGPAT2 pathogenic variants Pathogenic

Gene: AGPAT2 hgnc:325

Null and missense AGPAT2 variants can reduce or abolish lysophosphatidic acid acyltransferase activity.

Functional effects

AGPAT2 triglyceride biosynthesis loss-of-function

Impairs triacylglycerol synthesis and storage in adipocytes.

Show evidence (1 reference)

PMID:11967537 SUPPORT DIRECT Human Clinical

"We conclude that mutations in AGPAT2 may cause congenital generalized lipodystrophy by inhibiting triacylglycerol synthesis and storage in adipocytes."

The paper states the proposed functional effect of AGPAT2 mutations.

BSCL2 pathogenic variants (Causative biallelic pathogenic variants)

Gene: BSCL2 hgnc:15832 gene page relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:11479539 SUPPORT DIRECT Human Clinical

"Most of the variants are null mutations and probably result in a severe disruption of the protein."

Founding BSCL2 families; not every allele is null.

Variants (1)

Biallelic BSCL2 pathogenic variants Pathogenic

Gene: BSCL2 hgnc:15832

Null and missense BSCL2 variants disrupt seipin-dependent lipid-droplet regulation and adipocyte differentiation.

Functional effects

Seipin lipid-droplet regulation loss-of-function

Disrupts lipid-droplet organization and terminal adipocyte differentiation.

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT In Vitro

"In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated..."

Cell-model evidence links seipin loss to lipid-droplet loss and adipocyte transcriptional silencing.

CAV1 pathogenic variants (Causative biallelic pathogenic variants)

Gene: CAV1 hgnc:1527 gene page relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (3 references)

PMID:18211975 SUPPORT DIRECT Human Clinical

"RESULTS: A homozygous nonsense mutation (p.Glu38X) was identified in CAV1 in a patient with BSCL born from a consanguineous union."

Original homozygous CAV1 nonsense variant; fibroblasts lack both caveolin-1 isoforms.

PMID:34643546 SUPPORT DIRECT Human Clinical

"Four patients, aged 8 months to 18 years, carried a new homozygous p.(His79Glnfs*3) CAV1 variant."

Primary extension of CGL3 beyond the founding case.

PMID:34643546 SUPPORT DIRECT Human Clinical

"Heterozygous parents and relatives (n = 9) were asymptomatic, without any metabolic abnormality."

Observation limited to this family; other heterozygous CAV1 variants cause distinct disorders.

Variants (2)

CAV1 p.Glu38Ter

Nonsense variant

Homozygous truncating allele in the founding patient, with loss of both caveolin-1 isoforms in fibroblasts.

Show evidence (1 reference)

PMID:18211975 SUPPORT DIRECT Human Clinical

"RESULTS: A homozygous nonsense mutation (p.Glu38X) was identified in CAV1 in a patient with BSCL born from a consanguineous union."

Original homozygous CAV1 nonsense variant; fibroblasts lack both caveolin-1 isoforms.

CAV1 p.His79GlnfsTer3

Frameshift variant

Homozygous frameshift in four related patients; nine heterozygous relatives in this family were clinically unaffected.

Show evidence (1 reference)

PMID:34643546 SUPPORT DIRECT Human Clinical

"Four patients, aged 8 months to 18 years, carried a new homozygous p.(His79Glnfs*3) CAV1 variant."

Primary extension of CGL3 beyond the founding case.

CAVIN1 pathogenic variants (Causative biallelic pathogenic variants)

Gene: CAVIN1 hgnc:9688 relationship_type: CAUSATIVE variant_origin: GERMLINE

Show evidence (1 reference)

PMID:20300641 SUPPORT DIRECT Human Clinical

"Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate leading to the detection of homozygous mutations (c.160delG, c.362dupT)."

Primary CAVIN1 families.

Variants (2)

CAVIN1 c.160delG

Frameshift variant

Reported homozygous truncating allele in CGL4 families.

Show evidence (1 reference)

PMID:20300641 SUPPORT DIRECT Human Clinical

"Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate leading to the detection of homozygous mutations (c.160delG, c.362dupT)."

Primary CAVIN1 families.

CAVIN1 c.362dupT

Frameshift variant

Reported homozygous truncating allele in the UK CGL4 patient.

Show evidence (1 reference)

PMID:20300641 SUPPORT DIRECT Human Clinical

"Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate leading to the detection of homozygous mutations (c.160delG, c.362dupT)."

Primary variant observation.

PPARG pathogenic variants (Rare biallelic pathogenic variants)

Gene: PPARG hgnc:9236 gene page relationship_type: CAUSATIVE variant_origin: GERMLINE

Autosomal recessive

Show evidence (3 references)

PMID:24980513 SUPPORT DIRECT Human Clinical

"She showed the hallmark features of a congenital, generalized lipodystrophy (CGL)."

The biallelic PPARG proband is reported as showing the hallmark features of congenital generalized lipodystrophy.

CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z SUPPORT Other

"Specifically, PPARG has two associated diseases, namely the more commonly associated autosomal dominant familial partial lipodystrophy (OMIM:604367), and the more rarely associated autosomal recessive congenital, generalized lipodystrophy."

ClinGen names the two PPARG diseases and assigns the autosomal recessive congenital generalized one, curated here, to the rarer of the two.

CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z SUPPORT Other

"with most cases presenting as familial partial lipodystrophy and two cases with congenital, generalized lipodystrophy"

Quantifies how rare this presentation is: two congenital generalized cases among the probands ClinGen curated.

💊

Medical Actions

15

Metreleptin replacement therapy

Action: Pharmacotherapy NCIT:C15986

Agent: Metreleptin NCIT:C170171

Platform: Protein replacement

Metreleptin with diet is a first-line therapy for metabolic and endocrine complications of generalized lipodystrophy. The final NIH open-label analysis included 45 congenital and 21 acquired cases; congenital-group changes at 12 months/last observation were −1.8 percentage points in HbA1c and −22.2% in triglycerides. Published NIH cohorts overlap. Treatment improves metabolism without restoring absent fat; pooled liver and glycemic effects are not CGL-specific estimates.

Mechanism Target:

RESTORES Leptin deficiency — Replacement of deficient leptin restores hormonal signaling without reversing the initiating adipose genetic defect.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"In generalized lipodystrophy, metreleptin (with diet) is a first-line treatment for metabolic and endocrine abnormalities"

Multi-society clinical guidance; evidence is often consensus-based.

Show evidence (5 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"In generalized lipodystrophy, metreleptin (with diet) is a first-line treatment for metabolic and endocrine abnormalities"

Multi-society clinical guidance; evidence is often consensus-based.

PMID:29644599 SUPPORT DIRECT Human Clinical

"In the full analysis set, reductions in mean HbA1c and fasting TGs, respectively, from baseline to month 12/LOCF were numerically greater in patients with acquired GL (−2.9% and −53.5%) than in patients with congenital GL (−1.8% and −22.2%)."

Subtype-specific analysis from an uncontrolled integrated study, including imputation; not a randomized CGL-only treatment effect.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Acute pancreatitis due to hypertriglyceridemia has occurred in patients who acutely discontinued or reduced metreleptin (47)."

Multi-society clinical guidance; evidence is often consensus-based.

+ 2 more references

Individualized nutritional management

Action: Dietary Intervention NCIT:C15447

Platform: Behavioral / lifestyle

Use balanced macronutrients, restrict simple sugars and excessive fat, and preserve linear growth in children. Avoid overfeeding to achieve normal BMI because fat loss distorts body-composition targets. Very-low-fat intake is reserved for chylomicronemia-associated acute pancreatitis; infant feeding may require specialist medium-chain triglyceride formulations.

Show evidence (4 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Most patients should follow diets with balanced macronutrient composition."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Overfeeding to achieve normal weight may worsen metabolic complications and hepatic steatosis."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Very-low-fat diets should be used in chylomicronemia-induced acute pancreatitis."

Multi-society clinical guidance; evidence is often consensus-based.

+ 1 more reference

Physical activity with cardiac and skeletal precautions

Platform: Behavioral / lifestyle

Encourage activity after appropriate cardiac assessment. Avoid strenuous exercise in CGL4 and cardiomyopathy, and contact sports with severe organomegaly or lytic bone lesions.

Show evidence (3 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients with subtypes of lipodystrophy predisposed to cardiomyopathy should undergo cardiac evaluation before initiating an exercise regimen."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Contact sports should be avoided in patients with severe hepatosplenomegaly and CGL patients with lytic bone lesions."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients with type 4 CGL should avoid strenuous exercise and can be treated with β-adrenergic blockers and other anti-arrhythmic medications to prevent catecholaminergic polymorphic ventricular tachycardia."

Disease-specific clinical synthesis.

Metformin

Action: Pharmacotherapy NCIT:C15986

Agent: metformin CHEBI:6801

Platform: Small molecule

Metformin is a first-line conventional agent for insulin resistance and diabetes, alongside diet and disease-directed leptin treatment when appropriate.

Mechanism Target:

MODULATES Severe insulin resistance — Metformin is a first-line conventional agent for insulin resistance and diabetes, alongside diet and disease-directed leptin treatment when appropriate.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Metformin is a first-line agent for diabetes and insulin resistance."

Multi-society clinical guidance; evidence is often consensus-based.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Metformin is a first-line agent for diabetes and insulin resistance."

Multi-society clinical guidance; evidence is often consensus-based.

Insulin therapy

Action: Pharmacotherapy NCIT:C15986

Agent: insulin CHEBI:145810

Platform: Peptide

Severe hyperglycemia can require high-dose or concentrated insulin. Injection-site selection and absorption need attention because subcutaneous fat is scarce; doses may fall substantially after metreleptin.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Insulin is effective for hyperglycemia. In some patients, concentrated preparations and high-doses may be required."

Multi-society clinical guidance; evidence is often consensus-based.

Triglyceride-lowering therapy

Action: Pharmacotherapy NCIT:C15986

Agent: omega-3 fatty acid CHEBI:25681

Platform: Small molecule

Fibrates and long-chain omega-3 fatty acids are used for severe hypertriglyceridemia. Their use in lipodystrophy is supported mainly by clinical experience. Consider myopathy risk, particularly in CGL4.

Mechanism Target:

MODULATES Circulating triglyceride excess — Fibrates and long-chain omega-3 fatty acids are used for severe hypertriglyceridemia. Their use in lipodystrophy is supported mainly by clinical experience. Consider myopathy risk, particularly in CGL4.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Fibrates and/or long-chain omega-3 fatty acids should be used for triglycerides >500 mg/dL and may be considered for triglycerides >200 mg/dL."

Multi-society clinical guidance; evidence is often consensus-based.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Fibrates and/or long-chain omega-3 fatty acids should be used for triglycerides >500 mg/dL and may be considered for triglycerides >200 mg/dL."

Multi-society clinical guidance; evidence is often consensus-based.

Statin therapy

Action: Pharmacotherapy NCIT:C15986

Agent: statin CHEBI:87631

Platform: Small molecule

Statins address atherogenic cholesterol alongside lifestyle measures, with attention to age, reproductive status and muscular adverse effects.

Show evidence (2 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Statins should be used concomitantly with lifestyle modification (after consideration of age, reproductive status, and tolerance)."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Statins and fibrates should be used with caution due to increased risk of myopathy, especially in the presence of known myositis or muscular dystrophy (68)."

Multi-society clinical guidance; evidence is often consensus-based.

CGL4 specialist arrhythmia management

Action: Pharmacotherapy NCIT:C15986

Agent: Beta-Adrenergic Antagonist NCIT:C29576

Platform: Small molecule

Specialist evaluation may include exercise-related rhythm assessment and beta-blockade. Nadolol was initiated in two affected siblings with exercise-induced polymorphic ventricular tachycardia; controlled efficacy was not reported. Implantable defibrillator or pacing decisions depend on individual risk.

Target Phenotypes: Arrhythmia HP:0011675

Show evidence (2 references)

PMID:20684003 SUPPORT DIRECT Human Clinical

"She has been started on nadolol to treat this condition."

Case-level treatment after exercise-induced polymorphic ventricular tachycardia; not an efficacy trial.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Some patients with type 4 CGL might even benefit from an implantable pacemaker or defibrillator."

Review recommendation requiring individualized electrophysiology assessment.

Metabolic, cardiac and renal surveillance

Platform: Other

Assess diabetes, triglycerides, liver enzymes, blood pressure and urine protein at least annually. Perform annual ECG and echocardiography in CGL. Obtain liver ultrasound at diagnosis and thereafter as indicated; assess puberty and reproductive symptoms. Complications or treatment changes require closer follow-up.

Show evidence (5 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Diabetes screening should be performed annually."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Electrocardiogram and echocardiogram should be performed annually in CGL and progeroid disorders, at diagnosis, and as clinically indicated in FPLD and AGL."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Urine protein should be measured annually using 24-hour urine collection or spot urine protein-to-creatinine ratio."

Multi-society clinical guidance; evidence is often consensus-based.

+ 2 more references

Medication and reproductive precautions

Platform: Other

Avoid oral estrogen because of severe hypertriglyceridemia and pancreatitis risk. Consider nonhormonal or progestin-only contraception; use transdermal estrogen if replacement is needed. Avoid niacin, which can worsen insulin resistance. Thiazolidinedione benefits in partial lipodystrophy should not be transferred to CGL without caution.

Show evidence (4 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Oral estrogens are contraindicated in lipodystrophy syndromes due to the risk of severe hypertriglyceridemia and acute pancreatitis."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"If estrogen replacement is needed, transdermal estrogen should be used."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Niacin exacerbates insulin resistance and should be avoided."

Disease-specific clinical synthesis.

+ 1 more reference

Specialist reproductive and pregnancy care

Platform: Other

Evaluate menstrual dysfunction and fertility, and coordinate high-risk pregnancy care for diabetes and triglycerides. Metreleptin continuation or withdrawal during pregnancy requires individualized specialist assessment because fetal data are limited and withdrawal may worsen metabolic disease.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Pregnant patients should receive prenatal care from an obstetrician experienced in managing diabetes and a physician experienced in managing lipodystrophy."

Multi-society clinical guidance; evidence is often consensus-based.

Psychological and developmental support

Platform: Behavioral / lifestyle

Offer support for distress, body-image concerns and stigma; provide educational support when intellectual impairment is present. Reconstructive consultation may be appropriate for functional or appearance concerns.

Show evidence (2 references)

PMID:41713690 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Psychosocial support is essential due to the high burden of psychological distress and stigma."

Current guideline position statement.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Special education might be necessary for individuals who also have an intellectual disability."

Disease-specific clinical synthesis.

Genetic counseling and family testing

Action: Genetic Counseling NCIT:C15240

Platform: Behavioral / lifestyle

Offer gene-specific recurrence counseling and testing of at-risk relatives. Discuss prenatal testing when familial variants are known. For PPARG, a single allele can cause partial lipodystrophy and should not automatically be treated as an asymptomatic carrier state.

Show evidence (1 reference)

PMID:20301391 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Carrier testing for at-risk relatives and prenatal testing for pregnancies at increased risk are possible if the pathogenic variants in the family are known."

Historical chapter recommendation with PPARG-specific qualification.

Investigational mibavademab

Platform: Monoclonal antibody

Mibavademab (REGN4461) is an investigational leptin-receptor agonist antibody. Generalized-lipodystrophy phase II and switch studies are completed, and phase III LAGO is recruiting as of the September 2026 registry update. Trial inclusion of congenital disease does not establish efficacy in every CGL genotype.

Show evidence (1 reference)

clinicaltrials:NCT06548100 SUPPORT DIRECT Human Clinical

"The aim of the study is to see how safe and tolerable mibavademab is when switching from treatment with metreleptin."

Registry describes investigational use, not proven benefit.

Selected adjunctive diabetes therapies

Action: Pharmacotherapy NCIT:C15986

Platform: Other

GLP-1 receptor agonists or SGLT2 inhibitors may be considered in selected patients by specialists. The 2026 guideline discusses generalized and partial lipodystrophies together; it does not establish CGL-specific comparative efficacy.

Show evidence (1 reference)

PMID:41713690 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Adjunctive therapies, including glucagon-like peptide-1 receptor agonists and SGLT2 inhibitors, may offer additional metabolic benefit in selected cases."

Guideline-level option across mixed lipodystrophy populations.

🔬

Biochemical Markers

3

Hypertriglyceridemia (INCREASED)

Context: Circulating triglycerides are increased because adipose storage is severely impaired and lipid handling is diverted to non-adipose tissues.

Pathograph Readouts

Readout Of Circulating triglyceride excess Positive Diagnostic

Circulating triglycerides measure the systemic triglyceride excess, not the quantity stored in liver or muscle.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and adolescence and only rarely during infancy."

Review identifies hypertriglyceridemia as a common circulating biochemical abnormality in CGL.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and adolescence and only rarely during infancy."

The review summarizes hypertriglyceridemia prevalence in CGL.

Low leptin concentration (DECREASED)

Context: Near-total adipose tissue loss produces markedly reduced leptin levels, supporting replacement therapy in generalized lipodystrophy.

Pathograph Readouts

Readout Of Leptin deficiency Negative

Low circulating leptin reports the hypoleptinemic metabolic branch caused by near-total adipose tissue loss.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near total loss of fat."

Review provides low circulating leptin measurements in CGL patients.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near total loss of fat."

The review summarizes low leptin levels in patients with CGL.

Hyperinsulinemia (INCREASED)

Context: Hyperinsulinemia is a compensatory biochemical feature of severe insulin resistance.

Pathograph Readouts

Readout Of Severe insulin resistance Positive Diagnostic

Elevated circulating insulin reports compensation for severe insulin resistance.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal years."

Review identifies hyperinsulinemia as a common biochemical feature of CGL insulin resistance.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal years."

The review states that most patients develop hyperinsulinemia.

🔬

Diagnosis

3

Clinical lipodystrophy assessment

Recognize near-generalized lack of body fat from birth or infancy with metabolic findings. Document onset and depot distribution using examination and, where useful, DXA or MRI. CGL4 fat loss may progress in infancy; lack of obvious neonatal lipoatrophy does not exclude it.

disease screening NCIT:C15419

Results: Generalized lack of body fat with extreme muscularity supports CGL.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients with CGL have near-complete lack of fat starting at birth or infancy."

Multi-society clinical guidance; evidence is often consensus-based.

CGL molecular genetic testing

A phenotype-guided panel including AGPAT2, BSCL2, CAV1, CAVIN1 and rare PPARG presentations can define the molecular subtype. Negative testing does not exclude a genetic lipodystrophy; broader sequencing may be appropriate.

genetic testing NCIT:C15709

Results: Biallelic pathogenic variants in a known CGL gene support molecular diagnosis.

Show evidence (3 references)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Genotyping may include limited candidate gene sequencing, a panel of candidate genes, or whole-exome/whole-genome sequencing."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Because there is strong evidence for additional loci for genetic lipodystrophies, negative tests do not rule out a genetic condition."

Multi-society clinical guidance; evidence is often consensus-based.

PMID:20301391 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"The diagnosis of BSCL is established in a proband with three major criteria or two major criteria plus two or more minor criteria and/or by the identification of biallelic pathogenic variants in AGPAT2 or BSCL2."

Historical diagnostic framework; the current panel extends beyond the two genes in this retired chapter.

Metabolic workup and leptin interpretation

Assess glucose, insulin, triglycerides, liver disease and leptin in the clinical context. Low leptin supports the endocrine phenotype and treatment assessment but is not a stand-alone diagnostic cutoff.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Because serum leptin assays are not standardized and leptin concentrations in patients with lipodystrophy (especially partial forms) overlap the general population, leptin levels do not help in diagnosis but may help with the choice of therapies."

Multi-society clinical guidance; evidence is often consensus-based.

📈

Progression

1

Neonatal to childhood onset

Age: Birth to childhood

Generalized lipoatrophy is usually recognized at birth or in infancy, with metabolic complications often emerging during infancy, childhood, or puberty.

Show evidence (2 references)

ORPHA:528 SUPPORT Other

"Age of onset: Neonatal"

Orphanet records neonatal onset as one of the onset categories.

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Congenital generalized lipodystrophy (CGL) is a heterogeneous autosomal recessive disorder characterized by a near complete lack of adipose tissue from birth and, later in life, the development of metabolic complications, such as diabetes mellitus, hypertriglyceridaemia and hepatic steatosis."

The review states that CGL is characterized by near-complete adipose tissue absence from birth.

📊

Prevalence

1

Worldwide

Point Prevalence 0.1–0.9 per 100,000 1–9 per 1,000,000

Orphanet reports worldwide point prevalence in the 1-9 per 1,000,000 range.

Show evidence (1 reference)

ORPHA:528 SUPPORT Other

"1-9 / 1 000 000 | Worldwide | Point prevalence"

Orphanet provides the worldwide point-prevalence class.

🔀

Differential Diagnoses

3

Conditions with similar clinical presentations that must be differentiated from Berardinelli-Seip Congenital Lipodystrophy:

Familial Partial Lipodystrophy

Overlapping Features Partial inherited lipodystrophy typically preserves or increases fat in some depots. PPARG monoallelic disease usually belongs to this spectrum; rare biallelic CGL-like cases are represented here with explicit scope qualifications.

Distinguishing Features

Regional rather than near-total fat loss, often apparent around puberty.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Patients with FPLD have fat loss of the extremities typically occurring around puberty and can have a positive family history."

Clinical diagnostic distinction.

Acquired generalized lipodystrophy

Overlapping Features Acquired disease often develops after an interval of normal fat distribution and may be associated with autoimmunity. Early infancy onset can occasionally complicate the distinction.

Distinguishing Features

Prior normal fat distribution and associated autoimmunity favor acquired disease.

Show evidence (1 reference)

PMID:27710244 SUPPORT DIRECT REVIEW SYNTHESIS Human Clinical

"Review of photographs from infancy may distinguish CGL from AGL because infants typically show absent fat in CGL and normal fat in AGL."

Clinical distinction is useful but not absolute.

🔬

Clinical Trials

6

NCT00896298 PHASE_III COMPLETED

Phase II/III Randomized leptin-versus-placebo study enrolling 25 participants with partial or generalized lipodystrophy. Results are posted; the mixed population is not a CGL-only efficacy estimate.

Show evidence (1 reference)

clinicaltrials:NCT00896298 SUPPORT DIRECT Human Clinical

"The purpose of the study is to examine the safety and efficacy of Leptin on subjects with lipodystrophy."

Registry summary describes the study objective; recruitment and completion do not establish benefit.

NCT04159415 PHASE_II COMPLETED

Randomized sequential REGN4461 study in generalized lipodystrophy, with 16 actual participants and posted results. Congenital and acquired disease were eligible.

Show evidence (1 reference)

clinicaltrials:NCT04159415 SUPPORT DIRECT Human Clinical

"The primary objectives of the study are to estimate the effects of REGN4461 on glycemic parameters in the subset of patients with elevated baseline hemoglobin A1c levels (HbA1c ≥7%) and to estimate the effects of REGN4461 on fasting triglyceride levels in the subset of patients with elevated..."

Registry summary describes the study objective; recruitment and completion do not establish benefit.

NCT07220785 PHASE_III RECRUITING

LAGO randomized phase III study of mibavademab in congenital or acquired generalized lipodystrophy. Part A tests efficacy and Part B pediatric safety/pharmacokinetics. Planned enrollment is 28; no results are posted.

Show evidence (1 reference)

clinicaltrials:NCT07220785 SUPPORT DIRECT Human Clinical

"This is a 2-part study: Part A is an efficacy study in pediatric and adult participants, Part B is a safety and pharmacokinetic study in pediatric participants."

Registry summary describes the study objective; recruitment and completion do not establish benefit.

NCT06548100 PHASE_III COMPLETED

Single-arm study of nine participants switching from metreleptin to mibavademab after at least six months of metreleptin. No results were posted at the source check.

Show evidence (1 reference)

clinicaltrials:NCT06548100 SUPPORT DIRECT Human Clinical

"The aim of the study is to see how safe and tolerable mibavademab is when switching from treatment with metreleptin."

Registry summary describes the study objective; recruitment and completion do not establish benefit.

NCT06502990 PHASE_III TERMINATED

Metreleptin study in children under six with generalized lipodystrophy and diabetes and/or hypertriglyceridemia. One participant enrolled; the registry states closure because the study was no longer an EMA requirement, not because of demonstrated toxicity.

Show evidence (1 reference)

clinicaltrials:NCT06502990 SUPPORT DIRECT Human Clinical

"This is an open-label, Phase 3b study to evaluate effectiveness, safety and pharmacokinetic parameters of metreleptin in patients under 6 years of age with generalised lipodystrophy and associated diabetes mellitus and/or hypertriglyceridaemia"

Registry summary describes the study objective; recruitment and completion do not establish benefit.

NCT02325674 NOT_APPLICABLE RECRUITING

MEASuRE observational postauthorization registry follows metreleptin-treated patients for long-term safety and effectiveness. Includes US generalized disease and European generalized or partial disease; not a randomized treatment trial.

Show evidence (1 reference)

clinicaltrials:NCT02325674 SUPPORT DIRECT Human Clinical

"The study is a post-authorization, prospective, voluntary registry of patients treated with commercial metreleptin including, but not limited to, patients in the US and EEA."

Registry summary describes the study objective; recruitment and completion do not establish benefit.

🧫

Experimental Models

3

CAVIN1-deficient patient fibroblasts PRIMARY_CELL_CULTURE

Patient fibroblasts had a greater than 97% reduction in caveolae. Wild-type CAVIN1 transfection restored peripheral punctate caveolar staining. The experiment supports cell-autonomous caveola formation, without demonstrating clinical rescue.

Cell source

Patient-derived skin fibroblasts

Pathograph links

CAVIN1 caveola biogenesis defect recapitulates observes: cellular

Show evidence (1 reference)

PMID:20300641 SUPPORT DIRECT In Vitro

"Morphometric analysis by transmission electron microscopy of the quantity of caveolae on the cell surface revealed a severe reduction by >97% in the patient's fibroblasts (Figure 7A and 7B)."

Patient fibroblast ultrastructure.

Show evidence (2 references)

PMID:20300641 SUPPORT DIRECT In Vitro

"Morphometric analysis by transmission electron microscopy of the quantity of caveolae on the cell surface revealed a severe reduction by >97% in the patient's fibroblasts (Figure 7A and 7B)."

Patient fibroblast ultrastructure.

PMID:20300641 SUPPORT DIRECT In Vitro

"However, transfection of a construct into patient fibroblasts, which contained the full-length, wild-type PTRF-CAVIN gene cloned downstream of the eukaryotic CMV-promoter, reconstituted the punctate staining pattern at the cell periphery that corresponds to the caveolae (Figure 6E–6G)."

Rescue in cultured cells, not a clinical gene-therapy intervention.

CAV1-deficient patient fibroblasts PRIMARY_CELL_CULTURE

Fibroblasts lack caveolae and caveolin-1, caveolin-2 and cavin-1 protein expression, with impaired insulin responses, oxidative stress and premature senescence.

Cell source

Skin fibroblasts from a new CGL3 index patient and the previously reported patient

Pathograph links

CAV1-dependent caveola loss recapitulates observes: cellular

Show evidence (1 reference)

PMID:34643546 SUPPORT DIRECT In Vitro

"Patients' fibroblasts showed a complete loss of caveolae and no protein expression of caveolin-1 and its caveolin-2 and cavin-1 partners. Patients' fibroblasts also displayed insulin resistance, increased oxidative stress, and premature senescence."

Patient fibroblast caveolar phenotype.

Show evidence (1 reference)

PMID:34643546 SUPPORT DIRECT In Vitro

"Patients' fibroblasts also displayed insulin resistance, increased oxidative stress, and premature senescence."

Direct cultured patient-cell findings.

Bscl2-deficient adipogenic cultures PRIMARY_CELL_CULTURE

Knockout cultures retain early differentiation but fail terminal adipogenesis with excessive cAMP/PKA-dependent lipolysis. Lipolysis inhibitors largely rescue differentiation, whereas the tested PPARgamma agonist does not.

Cell source

Mouse embryonic fibroblasts and stromal vascular cells

Pathograph links

Unrestrained adipocyte lipolysis partially recapitulates observes: cellular

Limitations: Mouse-derived cells, not direct human adipocyte measurements.

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT In Vitro

"In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated..."

Knockout mouse-derived cells, not direct patient adipocyte measurements.

Failure of terminal adipocyte differentiation partially recapitulates observes: cellular

Limitations: The model resolves a cell-level sequence rather than all human subtype effects.

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT In Vitro

"In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated..."

Knockout mouse-derived cells, not direct patient adipocyte measurements.

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT In Vitro

"Importantly, such defects in differentiation can be largely rescued by inhibitors of lipolysis but not by a gamma peroxisome proliferator-activated receptor (PPARγ) agonist."

Experimental rescue does not establish clinical efficacy of a lipolysis inhibitor.

🐁

Animal Models

1

Bscl2 knockout mice

The model develops severe white-adipose lipodystrophy, insulin resistance and hepatic steatosis. Its fasting glucose and triglyceride behavior differs from human CGL2; reports of fasting reductions and postprandial hypertriglyceridemia should not be generalized to patients.

Species

Mus musculus

Genotype

Bscl2 homozygous knockout

Pathograph links

Generalized adipose tissue loss recapitulates observes: tissue

Show evidence (1 reference)

PMID:22269949 SUPPORT DIRECT Model Organism

"Bscl2(-/-) mice develop severe lipodystrophy of white adipose tissue (WAT), dyslipidemia, insulin resistance, and hepatic steatosis."

Primary knockout phenotype.

Show evidence (1 reference)

PMID:26239609 SUPPORT DIRECT REVIEW SYNTHESIS Model Organism

"however, these mice have lower plasma levels glucose and triglyceride upon fasting than wild-type mice, but have postprandial hypertriglyceridaemia."

Review synthesis of the model-specific metabolic limitation.

{ }

Source YAML

click to show

name: Berardinelli-Seip Congenital Lipodystrophy
category: Mendelian
creation_date: '2026-05-04T00:00:00Z'
synonyms:
- Congenital generalized lipodystrophy
- Berardinelli-Seip syndrome
- BSCL
- CGL
description: >
  Berardinelli-Seip congenital lipodystrophy is a rare autosomal recessive
  generalized lipodystrophy with near-total adipose tissue loss from birth or
  early infancy, muscular hypertrophy, severe insulin resistance,
  hypertriglyceridemia, hepatic steatosis, hepatomegaly, and early diabetes.
  The four numbered molecular subtypes are caused by biallelic pathogenic
  variants in AGPAT2, BSCL2, CAV1, and CAVIN1/PTRF; a further, much rarer form is
  caused by biallelic PPARG variants. These genes converge on impaired
  triglyceride or phospholipid handling, lipid-droplet biology, adipocyte
  differentiation, and caveola formation in adipocytes. Failure to
  store triglycerides in adipose tissue diverts lipid to liver and skeletal
  muscle and combines with severe leptin deficiency to drive the metabolic
  phenotype. Treatment is supportive and metabolic, including dietary
  management, conventional diabetes and hyperlipidemia therapy, and metreleptin
  replacement for generalized lipodystrophy.
disease_term:
  preferred_term: Berardinelli-Seip congenital lipodystrophy
  term:
    id: MONDO:0018883
    label: Berardinelli-Seip congenital lipodystrophy
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0018883
      label: Berardinelli-Seip congenital lipodystrophy
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
parents:
- Hereditary lipodystrophy
- Disorder of development or morphogenesis
has_subtypes:
- name: CGL1
  display_name: Type 1 (AGPAT2)
  description: >-
    AGPAT2-related CGL (OMIM 608594) predominantly removes metabolically active adipose depots, including marrow
    fat, while mechanical fat in palms, soles and orbital regions is relatively preserved. Lytic bone lesions
    are particularly associated with this subtype.
  subtype_term:
    preferred_term: Congenital generalized lipodystrophy type 1 (AGPAT2)
    term:
      id: MONDO:0012071
      label: congenital generalized lipodystrophy type 1
  genes:
  - preferred_term: AGPAT2
    term:
      id: hgnc:325
      label: AGPAT2
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated
      with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:11967537
    reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      We report several different mutations of the gene (AGPAT2) encoding 1-acylglycerol-3-phosphate O-acyltransferase
      2 in 20 affected individuals from 11 pedigrees of diverse ethnicities showing linkage to chromosome 9q34.
    explanation: >-
      Founding linkage and sequence study.
- name: CGL2
  display_name: Type 2 (BSCL2/seipin)
  description: >-
    BSCL2/seipin-related CGL (OMIM 269700) removes both metabolic and mechanical fat. Intellectual impairment
    is enriched compared with other genotypes; cardiomyopathy can occur across genotypes and was not significantly
    different between groups in the 70-patient genotype–phenotype study.
  subtype_term:
    preferred_term: Congenital generalized lipodystrophy type 2 (BSCL2)
    term:
      id: MONDO:0010020
      label: congenital generalized lipodystrophy type 2
  genes:
  - preferred_term: BSCL2
    term:
      id: hgnc:15832
      label: BSCL2
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated
      with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:11479539
    reference_title: Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Most of the variants are null mutations and probably result in a severe disruption of the protein.
    explanation: >-
      Founding BSCL2 families; not every allele is null.
- name: CGL3
  display_name: Type 3 (CAV1)
  description: >-
    Biallelic CAV1-related CGL (OMIM 612526) is extremely rare. Mechanical and marrow fat may be preserved.
    In addition to the original patient, four related patients were reported in 2021, with achalasia in two.
    Other heterozygous CAV1-associated disorders are distinct.
  subtype_term:
    preferred_term: Congenital generalized lipodystrophy type 3 (CAV1)
    term:
      id: MONDO:0012923
      label: congenital generalized lipodystrophy type 3
  genes:
  - preferred_term: CAV1
    term:
      id: hgnc:1527
      label: CAV1
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated
      with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - &id006
    reference: PMID:18211975
    reference_title: Association of a homozygous nonsense caveolin-1 mutation with Berardinelli-Seip congenital lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      RESULTS: A homozygous nonsense mutation (p.Glu38X) was identified in CAV1 in a patient with BSCL born
      from a consanguineous union.
    explanation: >-
      Original homozygous CAV1 nonsense variant; fibroblasts lack both caveolin-1 isoforms.
  - &id005
    reference: PMID:34643546
    reference_title: Biallelic CAV1 null variants induce congenital generalized lipodystrophy with achalasia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Four patients, aged 8 months to 18 years, carried a new homozygous p.(His79Glnfs*3) CAV1 variant.
    explanation: >-
      Primary extension of CGL3 beyond the founding case.
- name: CGL4
  display_name: Type 4 (CAVIN1/PTRF)
  description: >-
    Biallelic CAVIN1/PTRF-related CGL (OMIM 613327) combines loss of caveolae with lipodystrophy, myopathy
    and potentially life-threatening arrhythmia. Fat loss may progress during infancy. Mechanical and marrow
    fat can be preserved; muscle mounding, pyloric stenosis and atlantoaxial instability are characteristic
    additional findings.
  subtype_term:
    preferred_term: Congenital generalized lipodystrophy type 4 (CAVIN1)
    term:
      id: MONDO:0013225
      label: congenital generalized lipodystrophy type 4
  genes:
  - preferred_term: CAVIN1
    term:
      id: hgnc:9688
      label: CAVIN1
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Four distinct subtypes of CGL exist: type 1 is associated with AGPAT2 mutations; type 2 is associated
      with BSCL2 mutations; type 3 is associated with CAV1 mutations; and type 4 is associated with PTRF mutations.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - &id007
    reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes
      suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate
      leading to the detection of homozygous mutations (c.160delG, c.362dupT).
    explanation: >-
      Primary CAVIN1 families.
- name: CGL-PPARG
  display_name: PPARG-associated congenital generalized lipodystrophy
  description: >-
    A rare biallelic PPARG form of congenital generalized lipodystrophy. PPARG encodes the PPARgamma nuclear
    receptor that drives differentiation of preadipocytes into adipocytes. Monoallelic loss-of-function PPARG
    variants cause autosomal dominant familial partial lipodystrophy type 3, curated in the Familial Partial
    Lipodystrophy entry; the rare recessive cases have severe generalized or CGL-like lipoatrophy, with variable
    chronology and depot preservation. ClinGen therefore curates PPARG-related lipodystrophy as semidominant,
    and MONDO files this concept as a subclass of Berardinelli-Seip congenital lipodystrophy.
  subtype_term:
    preferred_term: PPARG-associated congenital generalized lipodystrophy
    term:
      id: MONDO:0979300
      label: PPARG-associated congenital generalized lipodystrophy
  genes:
  - preferred_term: PPARG
    term:
      id: hgnc:9236
      label: PPARG
  review_notes: >-
    This row rests on very few patients, and the sources do not agree that the phenotype is a pure generalized
    lipodystrophy. Dyment et al. (PMID:24980513) report their proband as showing the hallmark features of congenital
    generalized lipodystrophy, whereas Patni and Garg (PMID:26239609), reviewing the same case, record that
    she retained some facial adipose tissue, in contrast to a CGL phenotype, and that whether further biallelic
    patients show the same picture remains to be seen. ClinGen counts two congenital generalized lipodystrophy
    cases among at least 35 PPARG lipodystrophy probands. The 2024 PPARG review describes childhood fat loss
    progressing to upper limbs, back and abdomen in adulthood and includes facial involvement. The rare biallelic
    phenotype is therefore retained with explicit disagreement over distribution and chronology, rather than
    assuming every case has the classic neonatal near-total fat loss.
  evidence:
  - reference: PMID:24980513
    reference_title: "Biallelic mutations at PPARG cause a congenital, generalized lipodystrophy similar to the Berardinelli-Seip syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The phenotype and presence of two mutations suggests that biallelic mutations at PPARG cause a CGL similar to that observed with biallelic AGPAT2 or BSCL2 mutations."
    explanation: >-
      The report that places biallelic PPARG alongside AGPAT2 and BSCL2 as a cause of
      congenital generalized lipodystrophy, which is what makes this a subtype row on
      this entry rather than a separate disease.
    directness: DIRECT
  - reference: PMID:36806620
    reference_title: "Perinatal, metabolic, and reproductive features in PPARG-related lipodystrophy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "They carried monoallelic PPARG variants except a homozygous patient with congenital generalized lipodystrophy."
    explanation: >-
      A second cohort in which the one homozygous patient, unlike the 25 heterozygous
      patients, had congenital generalized lipodystrophy.
    directness: DIRECT
  - reference: CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z
    reference_title: "PPARG / lipodystrophy (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The occasional recessive cases typically feature early-onset, congenital generalized lipodystrophy, also known as Berardinelli-Seip syndrome, due to biallelic variants in PPARG (PMIDs:24980513, 36806620)."
    explanation: >-
      ClinGen's expert-panel narrative states that the recessive PPARG cases are
      early-onset congenital generalized lipodystrophy, i.e. this disease.
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "However, in contrast to a CGL phenotype, the patient had some facial adipose tissue."
    explanation: >-
      Cuts against the generalized characterization of this subtype: reviewing the
      index case, Patni and Garg record retained facial fat and judge the
      distribution not to be that of CGL. The row is kept with that qualification
      rather than as a settled generalized phenotype.
    directness: DIRECT
  - reference: PMID:39398333
    reference_title: "Familial partial lipodystrophy resulting from loss-of-function PPARγ pathogenic variants: phenotypic, clinical, and genetic features."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    directness: DIRECT
    snippet: >-
      It progressed to the upper limbs, back, and abdomen in adulthood, resembling the phenotypic pattern of
      generalized congenital lipodystrophies (CGL) (47).
    explanation: >-
      Review of the biallelic index case supports a CGL-like pattern but describes progression beyond infancy.
inheritance:
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    The congenital generalized presentation is recessive. When both parents carry the relevant pathogenic allele,
    each pregnancy has a 25% risk of the biallelic condition. Heterozygous PPARG alleles can cause partial
    lipodystrophy, so carrier counseling is gene- and allele-specific.
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Autosomal recessive"
    explanation: Orphanet records autosomal recessive inheritance.
  - reference: PMID:11967537
    reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Congenital generalized lipodystrophy is an autosomal recessive disorder characterized by marked paucity
      of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset
      of diabetes.
    explanation: The AGPAT2 discovery study states the autosomal recessive inheritance pattern.
    directness: DIRECT
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of
      being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
    explanation: >-
      Historical AGPAT2/BSCL2-focused counseling; asymptomatic-carrier wording is not extended to PPARG.
    quote_role: REVIEW_SYNTHESIS
prevalence:
- population: Worldwide
  measure_type: POINT_PREVALENCE
  prevalence_class: BAND_1_9_PER_1000000
  rate_low: 0.1
  rate_high: 0.9
  percentage: 1-9 per 1,000,000
  notes: >
    Orphanet reports worldwide point prevalence in the 1-9 per 1,000,000 range.
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "1-9 / 1 000 000 | Worldwide | Point prevalence"
    explanation: Orphanet provides the worldwide point-prevalence class.
progression:
- phase: Neonatal to childhood onset
  age_range: Birth to childhood
  notes: >
    Generalized lipoatrophy is usually recognized at birth or in infancy, with
    metabolic complications often emerging during infancy, childhood, or puberty.
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Age of onset: Neonatal"
    explanation: Orphanet records neonatal onset as one of the onset categories.
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Congenital generalized lipodystrophy (CGL) is a heterogeneous autosomal recessive disorder characterized
      by a near complete lack of adipose tissue from birth and, later in life, the development of metabolic
      complications, such as diabetes mellitus, hypertriglyceridaemia and hepatic steatosis.
    explanation: The review states that CGL is characterized by near-complete adipose tissue absence from birth.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
pathophysiology:
- name: AGPAT2 acylglycerol synthesis defect
  description: >-
    Loss of AGPAT2 impairs lysophosphatidic-acid acylation in adipocytes. This disrupts normal glycerolipid
    synthesis and adipogenesis. A global fall in phosphatidic acid is not assumed: compensatory hepatic pathways
    can increase particular phosphatidic-acid species in knockout mice.
  genes:
  - preferred_term: AGPAT2
    term:
      id: hgnc:325
      label: AGPAT2
  biological_processes:
  - preferred_term: triglyceride biosynthetic process
    term:
      id: GO:0019432
      label: triglyceride biosynthetic process
    modifier: DECREASED
  molecular_functions:
  - preferred_term: lysophosphatidic acid acyltransferase activity
    term:
      id: GO:0042171
      label: lysophosphatidic acid acyltransferase activity
    modifier: DECREASED
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  evidence:
  - reference: PMID:11967537
    reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The AGPAT2 enzyme catalyzes the acylation of lysophosphatidic acid to form phosphatidic acid, a key intermediate
      in the biosynthesis of triacylglycerol and glycerophospholipids.
    explanation: >-
      Biochemical function described as background in the human genetic discovery paper.
    quote_role: BACKGROUND
  downstream:
  - target: Generalized adipose tissue loss
    description: >-
      Disordered glycerolipid handling compromises adipose development and storage capacity.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:11967537
      reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        We conclude that mutations in AGPAT2 may cause congenital generalized lipodystrophy by inhibiting triacylglycerol
        synthesis and storage in adipocytes.
      explanation: >-
        The discovery paper proposes this route; the complete human cellular sequence is not directly measured.
  subtypes:
  - CGL1
- name: BSCL2 seipin lipid-droplet dysregulation
  description: >-
    Seipin deficiency disrupts lipid-droplet organization at the endoplasmic reticulum. Cell models also show
    dysregulated lipolysis, recorded as a separate downstream event.
  genes:
  - preferred_term: BSCL2
    term:
      id: hgnc:15832
      label: BSCL2
  biological_processes:
  - preferred_term: lipid droplet organization
    term:
      id: GO:0034389
      label: lipid droplet organization
    modifier: ABNORMAL
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Seipin has been postulated to have an important role in lipid droplet assembly and in adipocyte differentiation.
    explanation: >-
      Mechanistic synthesis; detailed seipin functions remain model-dependent.
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Unrestrained adipocyte lipolysis
    description: >-
      Seipin loss permits excessive cAMP/PKA-driven lipolysis in the reported cell models.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:22269949
      reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: >-
        In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular
        cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal
        differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated lipolysis,
        which leads to loss of lipid droplets and silencing of the expression of adipose tissue-specific transcription
        factors.
      explanation: >-
        Knockout mouse-derived cells, not direct patient adipocyte measurements.
  - target: Intellectual disability
    description: >-
      BSCL2-associated disease is enriched for intellectual impairment through an unresolved neurological mechanism.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:12362029
      reference_title: Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Notably, subjects with BSCL2 had a significantly higher prevalence of intellectual impairment than
        those with BSCL1 or BSCLX (p<0.0001, OR 17.0, CI 3.6 to 79.0).
      explanation: >-
        Human genotype association does not establish a lipid-droplet mechanism for intellectual disability.
  subtypes:
  - CGL2
  cellular_components:
  - preferred_term: lipid droplet
    term:
      id: GO:0005811
      label: lipid droplet
- name: Unrestrained adipocyte lipolysis
  description: >-
    Bscl2-deficient mouse-derived cells show excessive cAMP/PKA-dependent lipolysis during differentiation.
  biological_scale: CELLULAR
  evidence:
  - &id001
    reference: PMID:22269949
    reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: >-
      In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular
      cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal
      differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated lipolysis,
      which leads to loss of lipid droplets and silencing of the expression of adipose tissue-specific transcription
      factors.
    explanation: >-
      Knockout mouse-derived cells, not direct patient adipocyte measurements.
  downstream:
  - target: Failure of terminal adipocyte differentiation
    description: >-
      Excessive lipolysis disrupts completion of adipogenesis in this model.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:22269949
      reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: DIRECT
      snippet: >-
        In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular
        cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal
        differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated lipolysis,
        which leads to loss of lipid droplets and silencing of the expression of adipose tissue-specific transcription
        factors.
      explanation: >-
        Knockout mouse-derived cells, not direct patient adipocyte measurements.
  subtypes:
  - CGL2
- name: Failure of terminal adipocyte differentiation
  description: >-
    Early adipogenic differentiation can begin, but Bscl2-deficient cells fail to maintain terminal differentiation
    and adipocyte-specific transcription.
  biological_scale: CELLULAR
  evidence:
  - *id001
  downstream:
  - target: Generalized adipose tissue loss
    description: >-
      Failure to form and maintain mature adipocytes contributes to loss of adipose tissue.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:22269949
      reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: >-
        In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular
        cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal
        differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated lipolysis,
        which leads to loss of lipid droplets and silencing of the expression of adipose tissue-specific transcription
        factors.
      explanation: >-
        Knockout mouse-derived cells, not direct patient adipocyte measurements.
  subtypes:
  - CGL2
- name: CAV1-dependent caveola loss
  description: >-
    Biallelic CAV1 loss disrupts caveola formation. Patient fibroblasts lack caveolae and caveolar proteins.
    Adipose storage and insulin-response effects are supported by these patient cells and experimental models;
    each tissue need not have identical changes. The adipocyte binding identifies the disease-relevant cell
    type; the directly cited caveola and insulin-response assays were performed in fibroblasts, not patient
    adipocytes.
  genes:
  - preferred_term: CAV1
    term:
      id: hgnc:1527
      label: CAV1
  biological_processes:
  - preferred_term: caveola assembly
    term:
      id: GO:0070836
      label: caveola assembly
    modifier: DECREASED
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  evidence:
  - &id009
    reference: PMID:34643546
    reference_title: Biallelic CAV1 null variants induce congenital generalized lipodystrophy with achalasia.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: >-
      Patients' fibroblasts showed a complete loss of caveolae and no protein expression of caveolin-1 and
      its caveolin-2 and cavin-1 partners. Patients' fibroblasts also displayed insulin resistance, increased
      oxidative stress, and premature senescence.
    explanation: >-
      Patient fibroblast caveolar phenotype.
  downstream:
  - target: Generalized adipose tissue loss
    description: >-
      CAV1 deficiency compromises adipose maintenance; the complete intervening sequence remains unresolved.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:18211975
      reference_title: Association of a homozygous nonsense caveolin-1 mutation with Berardinelli-Seip congenital lipodystrophy.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        RESULTS: A homozygous nonsense mutation (p.Glu38X) was identified in CAV1 in a patient with BSCL born
        from a consanguineous union.
      explanation: >-
        Original homozygous CAV1 nonsense variant; fibroblasts lack both caveolin-1 isoforms.
  - target: CGL3 achalasia
    description: >-
      Biallelic CAV1 loss is associated with achalasia through an unresolved esophageal mechanism.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:34643546
      reference_title: Biallelic CAV1 null variants induce congenital generalized lipodystrophy with achalasia.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Two patients also presented at the age of 15 and 18 years with dysphagia due to achalasia, and one
        patient
        had retinitis pigmentosa.
      explanation: >-
        Primary CGL3 family.
  subtypes:
  - CGL3
- name: CAVIN1 caveola biogenesis defect
  description: >-
    CAVIN1 deficiency markedly reduces caveolae in patient fibroblasts and skeletal muscle. Caveolin localization
    is abnormal; reported abundance differs between studies, with preserved caveolin-1/3 in one cohort and
    reduced protein in another.
  genes:
  - preferred_term: CAVIN1
    term:
      id: hgnc:9688
      label: CAVIN1
  biological_processes:
  - preferred_term: caveola assembly
    term:
      id: GO:0070836
      label: caveola assembly
    modifier: DECREASED
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  evidence:
  - reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: >-
      Morphometric analysis by transmission electron microscopy of the quantity of caveolae on the cell surface
      revealed a severe reduction by >97% in the patient's fibroblasts (Figure 7A and 7B).
    explanation: >-
      Direct quantification of caveola loss in patient fibroblasts.
  - reference: PMID:19726876
    reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all 3
      caveolin family members, and reduction of caveolae structure.
    explanation: >-
      Human biopsy localization abnormalities.
  downstream:
  - target: Generalized adipose tissue loss
    description: >-
      Loss of caveolae impairs adipose maintenance.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:20684003
      reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        All patients had near total loss of body fat and congenital myopathy manifesting as weakness, percussion-induced
        muscle mounding, and high serum creatine kinase levels.
      explanation: >-
        Five patients with PTRF null variants had near-total fat loss; the intermediate adipocyte mechanism
        remains unresolved.
  - target: CGL4 congenital myopathy
    description: >-
      Caveolar disruption is associated with muscle dysfunction; tissue-specific intermediates remain incomplete.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:19726876
      reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all
        3 caveolin family members, and reduction of caveolae structure.
      explanation: >-
        Patient muscle pathology supports the myopathic phenotype.
  - target: CGL4 cardiac arrhythmia risk
    description: >-
      Cardiac electrophysiological consequences involve unresolved intermediates.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:20300641
      reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        In contrast to the “classic” variants, symptoms were more widespread comprising myopathy, smooth and
        skeletal muscle hypertrophy, cardiac arrhythmias, osteopenia and distal metaphyseal deformation with
        joint stiffness.
      explanation: >-
        Cardiac observations support risk; proposed ion-channel clustering mechanisms are not demonstrated
        in patient cardiomyocytes.
  - target: CGL4 muscle mounding
    description: >-
      Caveolar disease is associated with this subtype manifestation; detailed tissue-specific intermediates
      remain unresolved.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:19726876
      reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase
        levels were observed in these patients.
      explanation: >-
        Primary clinical observations.
  - target: CGL4 prolonged QT interval
    description: >-
      Caveolar disease is associated with this subtype manifestation; detailed tissue-specific intermediates
      remain unresolved.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:20300641
      reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        The corrected QT-time was between 430–501 ms (Figure 2E).
      explanation: >-
        One directly described CGL4 patient.
  - target: CGL4 polymorphic ventricular tachycardia
    description: >-
      Caveolar disease is associated with this subtype manifestation; detailed tissue-specific intermediates
      remain unresolved.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:20684003
      reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Therefore, an exercise study was conducted which revealed several runs of asymptomatic polymorphic
        ventricular tachycardia (Fig. 3C).
      explanation: >-
        Primary exercise-test observation.
  - target: CGL4 pyloric stenosis
    description: >-
      Subtype-associated structural manifestation; the intervening developmental mechanism remains uncertain.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:20684003
      reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Two patients belonging to CGL178 pedigree required surgery for pyloric stenosis in the first month
        of
        life.
      explanation: >-
        Primary CGL4 case series.
  - target: CGL4 atlantoaxial instability
    description: >-
      Subtype-associated structural manifestation; the intervening developmental mechanism remains uncertain.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:20684003
      reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Three of them had atlantoaxial instability. Two patients belonging to CGL178 pedigree required surgery
        for pyloric stenosis in the first month of life.
      explanation: >-
        Primary CGL4 case series.
  subtypes:
  - CGL4
- name: PPARG adipogenic nuclear receptor deficiency
  description: >-
    Reduced PPARgamma transcriptional function compromises adipocyte differentiation. Rare biallelic cases
    have a severe generalized or CGL-like distribution; heterozygous alleles may themselves cause partial lipodystrophy.
    The generalized boundary remains qualified by the subtype evidence.
  genes:
  - preferred_term: PPARG
    term:
      id: hgnc:9236
      label: PPARG
  biological_processes:
  - preferred_term: preadipocyte differentiation into adipocytes
    term:
      id: GO:0045444
      label: fat cell differentiation
    modifier: DECREASED
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
  evidence:
  - reference: PMID:39398333
    reference_title: "Familial partial lipodystrophy resulting from loss-of-function PPARγ pathogenic variants: phenotypic, clinical, and genetic features."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: BACKGROUND
    snippet: "PPARγ plays an essential role in adipogenesis, stimulating the differentiation of preadipocytes into adipocytes."
    explanation: >-
      The quoted statement describes established receptor biology, not a measurement in the reviewed patients.
      OTHER with BACKGROUND is appropriate for this gene-level function; the same review is graded HUMAN_CLINICAL
      with REVIEW_SYNTHESIS when it summarizes the biallelic patient phenotype in the subtype record.
    directness: DIRECT
  - reference: CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z
    reference_title: "PPARG / lipodystrophy (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Both loss of function and dominant negative variants have been reported."
    explanation: >-
      Supports the DECREASED direction on the adipogenic function: the reported
      variant classes reduce rather than increase PPARgamma activity.
  - reference: PMID:24980513
    reference_title: "Biallelic mutations at PPARG cause a congenital, generalized lipodystrophy similar to the Berardinelli-Seip syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Sequencing PPARG identified two pathogenic mutations; c.413_416delAATG; p.Glu138ValfsX168 and c.490C>T; p.R164W."
    explanation: >-
      The two PPARG variants carried by the index patient, one frameshift and one
      missense, establishing the biallelic lesion this node starts from.
    directness: DIRECT
  downstream:
  - target: Generalized adipose tissue loss
    description: >-
      Impaired adipogenesis underlies severe fat loss in rare biallelic cases.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:24980513
      reference_title: "Biallelic mutations at PPARG cause a congenital, generalized lipodystrophy similar to the Berardinelli-Seip syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The phenotype and presence of two mutations suggests that biallelic mutations at PPARG cause a CGL similar to that observed with biallelic AGPAT2 or BSCL2 mutations."
      explanation: >-
        The report that places biallelic PPARG alongside AGPAT2 and BSCL2 as a cause of
        congenital generalized lipodystrophy, which is what makes this a subtype row on
        this entry rather than a separate disease.
      directness: INDIRECT
  subtypes:
  - CGL-PPARG
- name: Generalized adipose tissue loss
  description: >-
    Adipose triglyceride storage capacity is profoundly reduced. Metabolic and mechanical depot involvement
    differs by genotype, and CGL4 fat loss may be progressive in infancy.
  cell_types:
  - preferred_term: adipocyte
    term:
      id: CL:0000136
      label: adipocyte
    modifier: DECREASED
  locations:
  - preferred_term: adipose tissue
    term:
      id: UBERON:0001013
      label: adipose tissue
    modifier: DECREASED
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "generalized lipoatrophy with acromegaloid features"
    explanation: Orphanet's definition supports generalized lipoatrophy as a core feature.
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Congenital generalized lipodystrophy (CGL) is a heterogeneous autosomal recessive disorder characterized
      by a near complete lack of adipose tissue from birth and, later in life, the development of metabolic
      complications, such as diabetes mellitus, hypertriglyceridaemia and hepatic steatosis.
    explanation: The review describes near-complete adipose tissue absence in CGL.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Lipodystrophy
    description: Near-total adipose loss clinically manifests as generalized lipodystrophy.
    causal_link_type: DIRECT
    evidence:
    - reference: ORPHA:528
      reference_title: "Congenital generalized lipodystrophy"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0009125 | Lipodystrophy | Very frequent (99-80%)"
      explanation: Orphanet records lipodystrophy as a very frequent phenotype of congenital generalized lipodystrophy.
  - target: Adipose tissue loss
    description: Loss of adipocytes produces the HPO adipose tissue loss phenotype.
    causal_link_type: DIRECT
    evidence:
    - reference: ORPHA:528
      reference_title: "Congenital generalized lipodystrophy"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0008887 | Adipose tissue loss | Very frequent (99-80%)"
      explanation: Orphanet records adipose tissue loss as a very frequent phenotype.
  - target: Ectopic triglyceride accumulation
    description: Inability to store triglyceride in adipose tissue diverts lipid to non-adipose organs.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Near-total adipose loss limits efficient storage of circulating triglycerides.
    - Excess triglycerides spill over to liver and skeletal muscle.
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The predominant cause of metabolic complications in CGL is excess triglyceride accumulation in the
        liver and skeletal muscle owing to the inability to store triglycerides in adipose tissue.
      explanation: Review identifies failure of adipose triglyceride storage as the driver of ectopic triglyceride accumulation.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  - target: Prominent superficial veins
    description: Near-total subcutaneous adipose loss can make superficial veins conspicuous.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Reduced subcutaneous fat coverage
    evidence:
    - reference: ORPHA:528
      reference_title: "Congenital generalized lipodystrophy"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0001015 | Prominent superficial veins | Occasional (29-5%)"
      explanation: Orphanet records prominent superficial veins as an occasional congenital generalized lipodystrophy phenotype.
  - target: Leptin deficiency
    description: >-
      Loss of adipose endocrine tissue lowers leptin.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near
        total loss of fat.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
  - target: Circulating triglyceride excess
    description: >-
      Deficient adipose storage contributes to circulating lipid excess.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood
        and adolescence and only rarely during infancy.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
- name: Leptin deficiency
  description: >-
    Markedly reduced adipose mass results in severe hypoleptinemia.
  biological_scale: ORGANISM
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near
      total loss of fat.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Increased appetite
    description: >-
      Leptin deficiency increases appetite.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Profound hypoleptinaemia in patients with CGL further exacerbates metabolic derangements by inducing
        hyperphagia.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
  - target: Severe insulin resistance
    description: >-
      Leptin has metabolic actions beyond appetite; their complete cellular route is not resolved.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:29723161
      reference_title: Metreleptin-mediated improvements in insulin sensitivity are independent of food intake in humans with lipodystrophy.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        CONCLUSION: Using lipodystrophy as a human model of leptin deficiency and replacement, we show that
        metreleptin improves insulin sensitivity and decreases hepatic and circulating triglycerides and that
        these improvements are independent of its effects on food intake.
      explanation: >-
        Nonrandomized metabolic-ward study: all eight withdrawal participants had generalized lipodystrophy;
        initiation participants were predominantly partial. Exact CGL-specific effects are not established.
  - target: Low leptin concentration
    description: >-
      The low serum measurement reflects deficient circulating leptin.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near
        total loss of fat.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
- name: Increased appetite
  description: >-
    Loss of leptin satiety signaling increases appetite and food intake.
  biological_scale: ORGANISM
  evidence:
  - &id002
    reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Profound hypoleptinaemia in patients with CGL further exacerbates metabolic derangements by inducing
      hyperphagia.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Ectopic triglyceride accumulation
    description: >-
      Excess intake adds to the lipid load that cannot be stored in adipose depots.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        The predominant cause of metabolic complications in CGL is excess triglyceride accumulation in the
        liver and skeletal muscle owing to the inability to store triglycerides in adipose tissue.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
  - target: Hyperphagia
    description: >-
      Increased appetite manifests clinically as hyperphagia.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Profound hypoleptinaemia in patients with CGL further exacerbates metabolic derangements by inducing
        hyperphagia.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
  - target: Accelerated growth
    description: >-
      High appetite is associated with accelerated childhood growth in the clinical synthesis; endocrine and
      nutritional intermediates are not fully specified.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Children with CGL have accelerated growth owing to a voracious appetite.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
- name: Ectopic triglyceride accumulation
  description: >-
    Inadequate adipose storage favors lipid deposition in liver and other nonadipose tissues. Hepatic lipid
    burden and insulin resistance are associated, but triglyceride itself is not assumed to be the sole toxic
    mediator. Muscle lipid excess is not universal across subtypes or samples.
  chemical_entities:
  - preferred_term: triglyceride
    term:
      id: CHEBI:17855
      label: triglyceride
    modifier: INCREASED
  cell_types:
  - preferred_term: hepatocyte
    term:
      id: CL:0000182
      label: hepatocyte
  - preferred_term: cell of skeletal muscle
    term:
      id: CL:0000188
      label: cell of skeletal muscle
  locations:
  - preferred_term: liver
    term:
      id: UBERON:0002107
      label: liver
    modifier: INCREASED
  - preferred_term: skeletal muscle tissue
    term:
      id: UBERON:0001134
      label: skeletal muscle tissue
    modifier: INCREASED
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The predominant cause of metabolic complications in CGL is excess triglyceride accumulation in the liver
      and skeletal muscle owing to the inability to store triglycerides in adipose tissue.
    explanation: The review states the central mechanism for metabolic complications.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Hepatic steatosis
    description: Ectopic triglyceride accumulation in hepatocytes produces hepatic steatosis.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The predominant cause of metabolic complications in CGL is excess triglyceride accumulation in the
        liver and skeletal muscle owing to the inability to store triglycerides in adipose tissue.
      explanation: Review identifies excess hepatic triglyceride accumulation as the main metabolic mechanism.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  - target: Cirrhosis
    description: Chronic hepatic lipid injury in congenital generalized lipodystrophy can progress to cirrhosis in a subset of patients.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Some patients develop steatohepatitis, which can progress to fibrosis, cirrhosis or end-stage liver
        disease that requires liver transplantation.
      explanation: >-
        Intermediate inflammatory and fibrotic liver injury.
      quote_role: REVIEW_SYNTHESIS
  - target: Hepatomegaly
    description: Hepatic lipid accumulation contributes to liver enlargement.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Ectopic hepatic triglyceride accumulation causes hepatic steatosis.
    - Hepatic steatosis can enlarge the liver.
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Patients can have liver enlargement due to hepatic steatosis in infancy."
      explanation: Review links hepatic steatosis to liver enlargement in CGL.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  - target: Severe insulin resistance
    description: >
      Hepatic steatosis and intramyocellular lipid accumulation contribute to
      the severe insulin-resistance mechanism, although the intervening
      molecular steps remain incompletely defined.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "However, how hepatic steatosis and increased intramyocellular lipids induce insulin resistance has not been elucidated."
      explanation: >
        The review supports a causal connection from ectopic lipid deposition to
        insulin resistance while explicitly noting that the precise intermediates
        are unresolved.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
- name: Circulating triglyceride excess
  description: >-
    Reduced adipose lipid-storage capacity and metabolic dysregulation produce severe hypertriglyceridemia.
  biological_scale: ORGANISM
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and
      adolescence and only rarely during infancy.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  downstream:
  - target: Hypertriglyceridemia
    description: >-
      Circulating triglyceride excess is the biochemical phenotype.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood
        and adolescence and only rarely during infancy.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
  - target: Pancreatitis
    description: >-
      Extreme triglyceride elevation predisposes to pancreatic inflammation.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - &id003
      reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Severe hypertriglyceridaemia is often associated with eruptive xanthomas and recurrent pancreatitis,
        particularly in patients with uncontrolled diabetes mellitus.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
  - target: Eruptive xanthomas
    description: >-
      Severe lipid excess causes cutaneous lipid deposition.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - &id004
      reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Severe hypertriglyceridaemia is often associated with eruptive xanthomas and recurrent pancreatitis,
        particularly in patients with uncontrolled diabetes mellitus.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
- name: Severe insulin resistance
  description: >-
    Insulin action is severely impaired. Compensatory hyperinsulinemia may initially preserve glucose tolerance;
    diabetes develops when compensation is inadequate. Lipid and leptin pathways contribute through incompletely
    resolved intermediates.
  biological_processes:
  - preferred_term: insulin receptor signaling pathway
    term:
      id: GO:0008286
      label: insulin receptor signaling pathway
    modifier: DECREASED
  evidence:
  - reference: PMID:11967537
    reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Congenital generalized lipodystrophy is an autosomal recessive disorder characterized by marked paucity
      of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset
      of diabetes.
    explanation: The AGPAT2 discovery paper includes extreme insulin resistance in the clinical phenotype.
    directness: DIRECT
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "muscle hypertrophy, insulin resistance, hypertriglyceridemia"
    explanation: Orphanet includes insulin resistance as a defining feature.
  downstream:
  - target: Insulin resistance
    description: The mechanism directly produces the clinical insulin-resistance phenotype.
    causal_link_type: DIRECT
    evidence:
    - reference: ORPHA:528
      reference_title: "Congenital generalized lipodystrophy"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0000855 | Insulin resistance | Very frequent (99-80%)"
      explanation: Orphanet records insulin resistance as very frequent in congenital generalized lipodystrophy.
  - target: Hyperinsulinemia
    description: Pancreatic compensation for insulin resistance increases circulating insulin.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the
        pubertal years.
      explanation: >-
        The review documents hyperinsulinemia in the insulin-resistant disease; the pancreatic compensation
        step is physiological interpretation rather than a beta-cell measurement in this cohort.
      directness: INDIRECT
      quote_role: REVIEW_SYNTHESIS
    intermediate_mechanisms:
    - Compensatory pancreatic beta-cell insulin secretion raises circulating insulin.
  - target: Diabetes mellitus
    description: Severe insulin resistance predisposes to diabetes mellitus.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the
        pubertal years.
      explanation: Review supports diabetes as a downstream clinical complication of severe insulin resistance in CGL.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  - target: Acanthosis nigricans
    description: Chronic insulin resistance can produce acanthosis nigricans.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Acanthosis nigricans develops during early childhood or after puberty, and can affect the neck, axillae
        and groin regions, as well as other locations such as the trunk, hands, knees, elbows and ankles.
      explanation: Review supports acanthosis nigricans as a cutaneous manifestation in the insulin-resistance phase.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  - target: Hirsutism
    description: >-
      Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual
      mediators are incompletely established.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
        with primary or secondary amenorrhoea and polycystic ovaries.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Insulin resistance is suspected to be the main cause of excessive ovarian androgen production in these
        patients.
      explanation: >-
        Proposed disease-level mechanism, not direct proof of each reproductive consequence.
      quote_role: REVIEW_SYNTHESIS
  - target: Clitoromegaly
    description: >-
      Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual
      mediators are incompletely established.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
        with primary or secondary amenorrhoea and polycystic ovaries.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Insulin resistance is suspected to be the main cause of excessive ovarian androgen production in these
        patients.
      explanation: >-
        Proposed disease-level mechanism, not direct proof of each reproductive consequence.
      quote_role: REVIEW_SYNTHESIS
  - target: Irregular menstruation
    description: >-
      Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual
      mediators are incompletely established.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
        with primary or secondary amenorrhoea and polycystic ovaries.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Insulin resistance is suspected to be the main cause of excessive ovarian androgen production in these
        patients.
      explanation: >-
        Proposed disease-level mechanism, not direct proof of each reproductive consequence.
      quote_role: REVIEW_SYNTHESIS
  - target: Polycystic ovaries
    description: >-
      Insulin resistance and hyperandrogenism contribute to female reproductive manifestations; the individual
      mediators are incompletely established.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
        with primary or secondary amenorrhoea and polycystic ovaries.
      explanation: >-
        Disease-specific clinical synthesis.
      quote_role: REVIEW_SYNTHESIS
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Insulin resistance is suspected to be the main cause of excessive ovarian androgen production in these
        patients.
      explanation: >-
        Proposed disease-level mechanism, not direct proof of each reproductive consequence.
      quote_role: REVIEW_SYNTHESIS
phenotypes:
- name: Insulin resistance
  frequency: VERY_FREQUENT
  description: Severe insulin resistance is a core metabolic manifestation.
  phenotype_term:
    preferred_term: Insulin resistance
    term:
      id: HP:0000855
      label: Insulin resistance
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000855 | Insulin resistance | Very frequent (99-80%)"
    explanation: Orphanet records insulin resistance as very frequent.
- name: Hepatomegaly
  frequency: VERY_FREQUENT
  description: Liver enlargement is common and reflects hepatic lipid accumulation.
  phenotype_term:
    preferred_term: Hepatomegaly
    term:
      id: HP:0002240
      label: Hepatomegaly
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002240 | Hepatomegaly | Very frequent (99-80%)"
    explanation: Orphanet records hepatomegaly as very frequent.
- name: Skeletal muscle hypertrophy
  frequency: VERY_FREQUENT
  description: Affected individuals have prominent musculature from loss of subcutaneous fat and muscular hypertrophy.
  phenotype_term:
    preferred_term: Skeletal muscle hypertrophy
    term:
      id: HP:0003712
      label: Skeletal muscle hypertrophy
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003712 | Skeletal muscle hypertrophy | Very frequent (99-80%)"
    explanation: Orphanet records skeletal muscle hypertrophy as very frequent.
- name: Adipose tissue loss
  frequency: VERY_FREQUENT
  description: >-
    Near-total metabolic fat loss is generally recognized at birth or in infancy; mechanical depots vary by
    genotype and CGL4 can lose fat progressively after birth.
  phenotype_term:
    preferred_term: Adipose tissue loss
    term:
      id: HP:0008887
      label: Adipose tissue loss
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0008887 | Adipose tissue loss | Very frequent (99-80%)"
    explanation: Orphanet records adipose tissue loss as very frequent.
- name: Lipodystrophy
  frequency: VERY_FREQUENT
  description: The disorder is a generalized lipodystrophy with abnormal adipose tissue morphology and distribution.
  phenotype_term:
    preferred_term: Lipodystrophy
    term:
      id: HP:0009125
      label: Lipodystrophy
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0009125 | Lipodystrophy | Very frequent (99-80%)"
    explanation: Orphanet records lipodystrophy as very frequent.
- name: Diabetes mellitus
  frequency: FREQUENT
  description: >-
    Diabetes usually follows progressive insulin resistance, often around puberty, but can occur earlier. Historical
    estimates differ by source and ascertainment: GeneReviews reported 25–35% by ages 15–20, whereas the 2015
    review reported approximately 45% during puberty.
  phenotype_term:
    preferred_term: Diabetes mellitus
    term:
      id: HP:0000819
      label: Diabetes mellitus
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000819 | Diabetes mellitus | Frequent (79-30%)"
    explanation: Orphanet records diabetes mellitus as frequent.
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Affected individuals develop insulin resistance and approximately 25%-35% develop diabetes mellitus between
      ages 15 and 20 years.
    explanation: >-
      Historical GeneReviews age-specific estimate.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal
      years.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Hypertrichosis
  frequency: FREQUENT
  description: Increased hair growth is a frequent Orphanet phenotype.
  phenotype_term:
    preferred_term: Hypertrichosis
    term:
      id: HP:0000998
      label: Hypertrichosis
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000998 | Hypertrichosis | Frequent (79-30%)"
    explanation: Orphanet records hypertrichosis as frequent.
- name: Prominent superficial veins
  frequency: OCCASIONAL
  description: Prominent superficial veins are an occasional body-habitus manifestation of congenital generalized lipodystrophy.
  phenotype_term:
    preferred_term: Prominent superficial veins
    term:
      id: HP:0001015
      label: Prominent superficial veins
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001015 | Prominent superficial veins | Occasional (29-5%)"
    explanation: Orphanet provides the disease-phenotype association and frequency band.
- name: Intellectual disability
  description: >-
    Intellectual impairment is particularly associated with BSCL2-related disease. In a 70-patient study, the
    odds ratio for BSCL2 compared with other molecular groups was 17 (95% CI 3.6–79); this is not an overall
    disease frequency.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:12362029
    reference_title: Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Notably, subjects with BSCL2 had a significantly higher prevalence of intellectual impairment than those
      with BSCL1 or BSCLX (p<0.0001, OR 17.0, CI 3.6 to 79.0).
    explanation: >-
      Human genotype association does not establish a lipid-droplet mechanism for intellectual disability.
- name: Hypertriglyceridemia
  frequency: FREQUENT
  description: >-
    Hypertriglyceridemia was reported in more than 70% of cases summarized by the 2015 CGL review, often developing
    in later childhood or adolescence. This literature estimate is not an unbiased population frequency.
  phenotype_term:
    preferred_term: Hypertriglyceridemia
    term:
      id: HP:0002155
      label: Hypertriglyceridemia
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002155 | Hypertriglyceridemia | Frequent (79-30%)"
    explanation: Orphanet records hypertriglyceridemia as frequent.
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and
      adolescence and only rarely during infancy.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Hypercholesterolemia
  frequency: OCCASIONAL
  description: Hypercholesterolemia is an occasional dyslipidemia phenotype in congenital generalized lipodystrophy.
  phenotype_term:
    preferred_term: Hypercholesterolemia
    term:
      id: HP:0003124
      label: Hypercholesterolemia
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0003124 | Hypercholesterolemia | Occasional (29-5%)"
    explanation: Orphanet provides the disease-phenotype association and frequency band.
- name: Hepatic steatosis
  description: >-
    Hepatic triglyceride deposition produces fatty liver and may contribute to hepatomegaly. The retired GeneReviews
    chapter described steatotic hepatomegaly in all affected individuals, reflecting the classic phenotype.
    This is not a universal frequency across newer molecular subtypes: the primary five-patient CGL4 series
    documented hepatic steatosis in two.
  phenotype_term:
    preferred_term: Hepatic steatosis
    term:
      id: HP:0001397
      label: Hepatic steatosis
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients can have liver enlargement due to hepatic steatosis in infancy.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Hepatomegaly secondary to hepatic steatosis and skeletal muscle hypertrophy occur in all affected individuals.
    explanation: >-
      Historical GeneReviews description of classic BSCL; not an all-subtype prevalence estimate.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20684003
    reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Two of them had hepatic steatosis.
    explanation: >-
      Two of five molecularly characterized CGL4 patients; limits extension of the classic universal statement.
- name: Cirrhosis
  frequency: OCCASIONAL
  description: Cirrhosis is an occasional hepatic complication recorded in congenital generalized lipodystrophy.
  phenotype_term:
    preferred_term: Cirrhosis
    term:
      id: HP:0001394
      label: Cirrhosis
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001394 | Cirrhosis | Occasional (29-5%)"
    explanation: Orphanet provides the disease-phenotype association and frequency band.
- name: Acanthosis nigricans
  description: Acanthosis nigricans is a cutaneous manifestation of severe insulin resistance.
  phenotype_term:
    preferred_term: Acanthosis nigricans
    term:
      id: HP:0000956
      label: Acanthosis nigricans
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000956 | Acanthosis nigricans | Occasional (29-5%)"
    explanation: Orphanet records acanthosis nigricans as occasional.
  - reference: PMID:11479539
    reference_title: Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other clinical and biological features include acanthosis nigricans, hyperandrogenism, muscular hypertrophy,
      hepatomegaly, altered glucose tolerance or diabetes mellitus, and hypertriglyceridemia.
    explanation: The BSCL2 discovery paper lists acanthosis nigricans among clinical features.
    directness: DIRECT
- name: Hypertrophic cardiomyopathy
  frequency: OCCASIONAL
  description: Hypertrophic cardiomyopathy contributes to morbidity in a subset of patients.
  phenotype_term:
    preferred_term: Hypertrophic cardiomyopathy
    term:
      id: HP:0001639
      label: Hypertrophic cardiomyopathy
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001639 | Hypertrophic cardiomyopathy | Occasional (29-5%)"
    explanation: Orphanet records hypertrophic cardiomyopathy as occasional.
  - reference: PMID:12362029
    reference_title: Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In all subjects, hepatic dysfunction, hyperlipidaemia, diabetes mellitus, and hypertrophic cardiomyopathy
      were significant contributors to morbidity with no clear differences in their prevalence between subjects
      with BSCL1 or BSCL2 and those with evidence against cosegregation with either chromosome 9 or 11 (designated
      BSCLX).
    explanation: The genotype-phenotype cohort identifies hypertrophic cardiomyopathy as a morbidity contributor.
    directness: DIRECT
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Hypertrophic cardiomyopathy is reported in 20%-25% of affected individuals and is a significant cause
      of morbidity from cardiac failure and early mortality.
    explanation: >-
      Historical GeneReviews estimate, not a current subtype-specific risk.
    quote_role: REVIEW_SYNTHESIS
- name: Congestive heart failure
  frequency: OCCASIONAL
  description: Congestive heart failure is an occasional cardiac complication in congenital generalized lipodystrophy.
  phenotype_term:
    preferred_term: Congestive heart failure
    term:
      id: HP:0001635
      label: Congestive heart failure
  evidence:
  - reference: ORPHA:528
    reference_title: "Congenital generalized lipodystrophy"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0001635 | Congestive heart failure | Occasional (29-5%)"
    explanation: Orphanet provides the disease-phenotype association and frequency band.
- name: Hyperinsulinemia
  description: Hyperinsulinemia reflects compensation for severe insulin resistance.
  phenotype_term:
    preferred_term: Hyperinsulinemia
    term:
      id: HP:0000842
      label: Hyperinsulinemia
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal
      years.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: CGL4 congenital myopathy
  subtype: CGL4
  description: >
    CAVIN1/PTRF-associated type 4 disease includes congenital myopathy as a
    subtype-distinguishing neuromuscular feature.
  phenotype_term:
    preferred_term: Myopathy
    term:
      id: HP:0003198
      label: Myopathy
  evidence:
  - reference: PMID:20684003
    reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      All patients had near total loss of body fat and congenital myopathy manifesting as weakness, percussion-induced
      muscle mounding, and high serum creatine kinase levels.
    explanation: >-
      Congenital weakness and other myopathic findings in five patients from three CGL4 pedigrees.
  subtypes:
  - CGL4
- name: CGL4 elevated creatine kinase
  subtype: CGL4
  description: >
    Elevated serum creatine kinase accompanies the congenital myopathy reported
    in CAVIN1/PTRF-associated type 4 disease.
  phenotype_term:
    preferred_term: Elevated circulating creatine kinase activity
    term:
      id: HP:0003236
      label: Elevated circulating creatine kinase activity
  evidence:
  - reference: PMID:19726876
    reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase
      levels were observed in these patients.
    explanation: >-
      Five patients in a muscular-dystrophy-ascertained series.
  reports_on:
  - target: CAVIN1 caveola biogenesis defect
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: CAVIN1/PTRF-associated myopathy is accompanied by high serum creatine kinase.
    evidence:
    - reference: PMID:19726876
      reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase
        levels were observed in these patients.
      explanation: >-
        Five patients in a muscular-dystrophy-ascertained series.
  subtypes:
  - CGL4
- name: CGL4 cardiac arrhythmia risk
  subtype: CGL4
  description: >-
    CAVIN1-associated disease can cause exercise-induced polymorphic ventricular tachycardia, prolonged QT,
    ventricular fibrillation and sudden death. Normal resting testing or absence of QT prolongation does not
    exclude exercise-related risk.
  phenotype_term:
    preferred_term: Arrhythmia
    term:
      id: HP:0011675
      label: Arrhythmia
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "predisposition to serious arrhythmias such as catecholaminergic polymorphic ventricular tachycardia, long QT interval and sudden death"
    explanation: The CGL review identifies serious arrhythmias and sudden death as CGL4-specific risks.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
  subtypes:
  - CGL4
- name: Hyperphagia
  description: >-
    Increased appetite contributes to excess energy intake despite minimal adipose storage.
  phenotype_term:
    preferred_term: Polyphagia
    term:
      id: HP:0002591
      label: Polyphagia
  evidence:
  - *id002
- name: Pancreatitis
  description: >-
    Severe hypertriglyceridemia can cause recurrent pancreatitis.
  phenotype_term:
    preferred_term: Pancreatitis
    term:
      id: HP:0001733
      label: Pancreatitis
  evidence:
  - *id003
- name: Eruptive xanthomas
  description: >-
    Eruptive xanthomas accompany severe triglyceride elevation.
  phenotype_term:
    preferred_term: Xanthomatosis
    term:
      id: HP:0000991
      label: Xanthomatosis
  evidence:
  - *id004
- name: Low HDL cholesterol
  description: >-
    HDL cholesterol can be low in the metabolic phenotype.
  phenotype_term:
    preferred_term: Decreased circulating HDL cholesterol concentration
    term:
      id: HP:0003233
      label: Decreased HDL cholesterol concentration
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      HDL cholesterol levels also tend to be low.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Hirsutism
  description: >-
    Female hyperandrogenic features can include hirsutism.
  phenotype_term:
    preferred_term: Hirsutism
    term:
      id: HP:0001007
      label: Hirsutism
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
      with primary or secondary amenorrhoea and polycystic ovaries.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Clitoromegaly
  description: >-
    Clitoral enlargement is reported in affected females.
  phenotype_term:
    preferred_term: Clitoromegaly
    term:
      id: HP:0008665
      label: Clitoral hypertrophy
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
      with primary or secondary amenorrhoea and polycystic ovaries.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Irregular menstruation
  description: >-
    Menstrual irregularity or amenorrhea can accompany reproductive dysfunction.
  phenotype_term:
    preferred_term: Menstrual irregularities
    term:
      id: HP:0000858
      label: Irregular menstruation
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
      with primary or secondary amenorrhoea and polycystic ovaries.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Polycystic ovaries
  description: >-
    Polycystic ovaries occur in some affected females; reproductive manifestations are not assigned whole-cohort
    frequencies.
  phenotype_term:
    preferred_term: Polycystic ovaries
    term:
      id: HP:0000147
      label: Polycystic ovaries
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Mild hirsutism, clitoromegaly and irregular menstruation are common in women with CGL and some present
      with primary or secondary amenorrhoea and polycystic ovaries.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Proteinuria
  description: >-
    Renal disease can include proteinuria, diabetic nephropathy or focal segmental glomerulosclerosis.
  phenotype_term:
    preferred_term: Proteinuria
    term:
      id: HP:0000093
      label: Proteinuria
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Proteinuria is common (34). Kidney biopsy should be performed as clinically indicated, and pathology
      may include diabetic nephropathy, focal segmental glomerulosclerosis (especially in CGL) (34) or MPGN
      (especially in APL) (17).
    explanation: >-
      Guideline synthesis across lipodystrophies; no CGL-specific frequency inferred.
    quote_role: REVIEW_SYNTHESIS
- name: Focal segmental glomerulosclerosis
  description: >-
    Focal segmental glomerulosclerosis is a recognized renal lesion in CGL.
  phenotype_term:
    preferred_term: Focal segmental glomerulosclerosis
    term:
      id: HP:0000097
      label: Focal segmental glomerulosclerosis
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Kidney biopsy should be performed as clinically indicated, and pathology may include diabetic nephropathy,
      focal segmental glomerulosclerosis (especially in CGL) (34) or MPGN (especially in APL) (17).
    explanation: >-
      Guideline distinguishes CGL-associated FSGS from APL-associated MPGN.
    quote_role: REVIEW_SYNTHESIS
- name: Lytic bone lesions
  description: >-
    Focal lytic lesions, particularly in CGL1, may predispose to pathological fractures.
  phenotype_term:
    preferred_term: Osteolysis
    term:
      id: HP:0002797
      label: Osteolysis
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      These patients also have increased predisposition to develop lytic lesions in the appendicular skeleton
      (Table 1).
    explanation: >-
      AGPAT2 subtype context in the review.
    quote_role: REVIEW_SYNTHESIS
  subtypes:
  - CGL1
- name: CGL4 pyloric stenosis
  description: >-
    Pyloric stenosis can require surgery in CGL4.
  phenotype_term:
    preferred_term: Pyloric stenosis
    term:
      id: HP:0002021
      label: Pyloric stenosis
  evidence:
  - reference: PMID:20684003
    reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Two patients belonging to CGL178 pedigree required surgery for pyloric stenosis in the first month of
      life.
    explanation: >-
      Primary CGL4 case series.
  subtypes:
  - CGL4
- name: CGL4 atlantoaxial instability
  description: >-
    Cervical instability is reported in CAVIN1 disease; intervention is individualized.
  phenotype_term:
    preferred_term: Atlantoaxial instability
    term:
      id: HP:0003467
      label: Atlantoaxial instability
  evidence:
  - reference: PMID:20684003
    reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Three of them had atlantoaxial instability. Two patients belonging to CGL178 pedigree required surgery
      for pyloric stenosis in the first month of life.
    explanation: >-
      Primary CGL4 case series.
  subtypes:
  - CGL4
- name: CGL3 achalasia
  description: >-
    Two of four newly reported related CAV1 patients developed achalasia in adolescence.
  phenotype_term:
    preferred_term: Achalasia
    term:
      id: HP:0002571
      label: Achalasia
  evidence:
  - reference: PMID:34643546
    reference_title: Biallelic CAV1 null variants induce congenital generalized lipodystrophy with achalasia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Two patients also presented at the age of 15 and 18 years with dysphagia due to achalasia, and one patient
      had retinitis pigmentosa.
    explanation: >-
      Primary CGL3 family.
  subtypes:
  - CGL3
- name: CGL4 muscle mounding
  description: >-
    Percussion-induced local sustained contractions are characteristic; mounding may be electrically silent
    and is not equivalent to myotonia.
  phenotype_term:
    preferred_term: Muscle mounding
    term:
      id: HP:0003719
      label: Muscle mounding
  evidence:
  - reference: PMID:19726876
    reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase
      levels were observed in these patients.
    explanation: >-
      Primary clinical observations.
  subtypes:
  - CGL4
- name: CGL4 prolonged QT interval
  description: >-
    QT prolongation occurs in some CAVIN1 families but was absent in the five-patient Shastry series despite
    exercise-induced arrhythmias.
  phenotype_term:
    preferred_term: Prolonged QT interval
    term:
      id: HP:0001657
      label: Prolonged QT interval
  evidence:
  - reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The corrected QT-time was between 430–501 ms (Figure 2E).
    explanation: >-
      One directly described CGL4 patient.
  subtypes:
  - CGL4
- name: CGL4 polymorphic ventricular tachycardia
  description: >-
    Exercise-induced polymorphic ventricular tachycardia resembling CPVT was documented in two siblings; resting
    assessment may be unrevealing.
  phenotype_term:
    preferred_term: Polymorphic ventricular tachycardia
    term:
      id: HP:0031677
      label: Polymorphic ventricular tachycardia
  evidence:
  - reference: PMID:20684003
    reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Therefore, an exercise study was conducted which revealed several runs of asymptomatic polymorphic ventricular
      tachycardia (Fig. 3C).
    explanation: >-
      Primary exercise-test observation.
  subtypes:
  - CGL4
- name: Umbilical hernia
  description: >-
    Umbilical prominence or hernia may be apparent from birth, sometimes in association with organomegaly.
  phenotype_term:
    preferred_term: Umbilical hernia
    term:
      id: HP:0001537
      label: Umbilical hernia
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Prominence of umbilicus or umbilical hernia is often noticed at birth, which is probably due to underlying
      hepatomegaly and/or splenomegaly.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Hypertension
  description: >-
    Blood pressure can be elevated and warrants surveillance; no whole-CGL frequency is inferred from mixed-lipodystrophy
    guidance.
  phenotype_term:
    preferred_term: Hypertension
    term:
      id: HP:0000822
      label: Hypertension
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Hypertension is common (25), even in children.
    explanation: >-
      Guideline synthesis across lipodystrophy syndromes, supported by subtype case reports.
    quote_role: REVIEW_SYNTHESIS
- name: Large hands
  description: >-
    Large hands form part of the acromegaloid appearance described particularly in CGL1.
  phenotype_term:
    preferred_term: Large hands
    term:
      id: HP:0001176
      label: Large hands
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients with type 1 CGL have a characteristic body fat distribution and might present with acromegaloid
      features with enlarged mandible, hands and feet (Figure 1a).
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: ORPHA:528
    reference_title: Congenital generalized lipodystrophy
    supports: SUPPORT
    evidence_source: OTHER
    directness: DIRECT
    snippet: >-
      HP:0001176 | Large hands | Occasional (29-5%)
    explanation: >-
      Orphanet disease-level frequency band.
  frequency: OCCASIONAL
- name: Mandibular prognathia
  description: >-
    Mandibular enlargement and prognathia contribute to the acromegaloid facial appearance, particularly in
    CGL1.
  phenotype_term:
    preferred_term: Mandibular prognathia
    term:
      id: HP:0000303
      label: Mandibular prognathia
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients with type 1 CGL have a characteristic body fat distribution and might present with acromegaloid
      features with enlarged mandible, hands and feet (Figure 1a).
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: ORPHA:528
    reference_title: Congenital generalized lipodystrophy
    supports: SUPPORT
    evidence_source: OTHER
    directness: DIRECT
    snippet: >-
      HP:0000303 | Mandibular prognathia | Occasional (29-5%)
    explanation: >-
      Orphanet disease-level frequency band.
  frequency: OCCASIONAL
- name: Macroglossia
  description: >-
    Tongue enlargement is an occasional component of the acromegaloid phenotype.
  phenotype_term:
    preferred_term: Macroglossia
    term:
      id: HP:0000158
      label: Macroglossia
  evidence:
  - reference: ORPHA:528
    reference_title: Congenital generalized lipodystrophy
    supports: SUPPORT
    evidence_source: OTHER
    directness: DIRECT
    snippet: >-
      HP:0000158 | Macroglossia | Occasional (29-5%)
    explanation: >-
      Orphanet disease-level frequency band.
  frequency: OCCASIONAL
- name: Proportionate tall stature
  description: >-
    Proportionate tall stature is an occasional feature; growth varies across molecular subtypes.
  phenotype_term:
    preferred_term: Proportionate tall stature
    term:
      id: HP:0011407
      label: Proportionate tall stature
  evidence:
  - reference: ORPHA:528
    reference_title: Congenital generalized lipodystrophy
    supports: SUPPORT
    evidence_source: OTHER
    directness: DIRECT
    snippet: >-
      HP:0011407 | Proportionate tall stature | Occasional (29-5%)
    explanation: >-
      Orphanet disease-level frequency band.
  frequency: OCCASIONAL
- name: Advanced bone age
  description: >-
    Advanced bone age is reported in nine individuals summarized in the 2015 review, without a cohort denominator.
  phenotype_term:
    preferred_term: Accelerated skeletal maturation
    term:
      id: HP:0005616
      label: Accelerated skeletal maturation
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Advanced bone age has also been reported in nine individuals.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: ORPHA:528
    reference_title: Congenital generalized lipodystrophy
    supports: SUPPORT
    evidence_source: OTHER
    directness: DIRECT
    snippet: >-
      HP:0005616 | Accelerated skeletal maturation | Occasional (29-5%)
    explanation: >-
      Orphanet disease-level frequency band.
  frequency: OCCASIONAL
- name: Accelerated growth
  description: >-
    Accelerated childhood growth is associated with marked appetite in the classic CGL phenotype.
  phenotype_term:
    preferred_term: Overgrowth
    term:
      id: HP:0001548
      label: Overgrowth
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Children with CGL have accelerated growth owing to a voracious appetite.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Splenomegaly
  description: >-
    Splenic enlargement can accompany hepatomegaly and abdominal prominence; no aggregate prevalence is established.
  phenotype_term:
    preferred_term: Splenomegaly
    term:
      id: HP:0001744
      label: Splenomegaly
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Prominence of umbilicus or umbilical hernia is often noticed at birth, which is probably due to underlying
      hepatomegaly and/or splenomegaly.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
biochemical:
- name: Hypertriglyceridemia
  presence: INCREASED
  context: >
    Circulating triglycerides are increased because adipose storage is severely
    impaired and lipid handling is diverted to non-adipose tissues.
  biomarker_term:
    preferred_term: triglyceride
    term:
      id: CHEBI:17855
      label: triglyceride
  readouts:
  - target: Circulating triglyceride excess
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Circulating triglycerides measure the systemic triglyceride excess, not the quantity stored in liver
      or muscle.
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood
        and adolescence and only rarely during infancy.
      explanation: Review identifies hypertriglyceridemia as a common circulating biochemical abnormality in CGL.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Hypertriglyceridaemia is present in >70% of patients with CGL and develops mostly in late childhood and
      adolescence and only rarely during infancy.
    explanation: The review summarizes hypertriglyceridemia prevalence in CGL.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
- name: Low leptin concentration
  presence: DECREASED
  context: >
    Near-total adipose tissue loss produces markedly reduced leptin levels,
    supporting replacement therapy in generalized lipodystrophy.
  biomarker_term:
    preferred_term: leptin
    term:
      id: NCIT:C46081
      label: Leptin
  readouts:
  - target: Leptin deficiency
    relationship: READOUT_OF
    direction: NEGATIVE
    interpretation: Low circulating leptin reports the hypoleptinemic metabolic branch caused by near-total adipose tissue loss.
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near
        total loss of fat.
      explanation: Review provides low circulating leptin measurements in CGL patients.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The serum levels of leptin and adiponectin are markedly reduced in patients with CGL secondary to near
      total loss of fat.
    explanation: The review summarizes low leptin levels in patients with CGL.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
  notes: >-
    No standardized leptin cutoff confirms or excludes lipodystrophy; interpret together with the fat distribution
    and metabolic phenotype.
- name: Hyperinsulinemia
  presence: INCREASED
  context: >
    Hyperinsulinemia is a compensatory biochemical feature of severe insulin
    resistance.
  biomarker_term:
    preferred_term: insulin
    term:
      id: NCIT:C2271
      label: Insulin
  readouts:
  - target: Severe insulin resistance
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated circulating insulin reports compensation for severe insulin resistance.
    evidence:
    - reference: PMID:26239609
      reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the
        pubertal years.
      explanation: Review identifies hyperinsulinemia as a common biochemical feature of CGL insulin resistance.
      directness: DIRECT
      quote_role: REVIEW_SYNTHESIS
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The majority of patients develop hyperinsulinaemia,41 and ~45% develop diabetes mellitus during the pubertal
      years.
    explanation: The review states that most patients develop hyperinsulinemia.
    directness: DIRECT
    quote_role: REVIEW_SYNTHESIS
genetic:
- name: AGPAT2 pathogenic variants
  subtype: CGL1
  gene_term:
    preferred_term: AGPAT2
    term:
      id: hgnc:325
      label: AGPAT2
  association: Causative biallelic pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:11967537
    reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      We report several different mutations of the gene (AGPAT2) encoding 1-acylglycerol-3-phosphate O-acyltransferase
      2 in 20 affected individuals from 11 pedigrees of diverse ethnicities showing linkage to chromosome 9q34.
    explanation: >-
      Founding linkage and sequence study.
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      However, the type of mutation does not seem to determine the phenotype or the severity of fat loss.
    explanation: >-
      AGPAT2 genotype–phenotype limitation.
    quote_role: REVIEW_SYNTHESIS
  variants:
  - name: Biallelic AGPAT2 pathogenic variants
    description: Null and missense AGPAT2 variants can reduce or abolish lysophosphatidic acid acyltransferase activity.
    gene:
      preferred_term: AGPAT2
      term:
        id: hgnc:325
        label: AGPAT2
    clinical_significance: PATHOGENIC
    functional_effects:
    - function: AGPAT2 triglyceride biosynthesis
      description: Impairs triacylglycerol synthesis and storage in adipocytes.
      type: loss-of-function
    evidence:
    - reference: PMID:11967537
      reference_title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We conclude that mutations in AGPAT2 may cause congenital generalized lipodystrophy by inhibiting triacylglycerol
        synthesis and storage in adipocytes.
      explanation: The paper states the proposed functional effect of AGPAT2 mutations.
      directness: DIRECT
  notes: >-
    Most reported alleles are null, with missense alleles also present. Broad variant class does not reliably
    predict severity; the c.589-2A>G allele is recurrent in patients of African ancestry. These are patient-series
    observations, not universal penetrance or population-frequency estimates.
- name: BSCL2 pathogenic variants
  subtype: CGL2
  gene_term:
    preferred_term: BSCL2
    term:
      id: hgnc:15832
      label: BSCL2
  association: Causative biallelic pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:11479539
    reference_title: Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Most of the variants are null mutations and probably result in a severe disruption of the protein.
    explanation: >-
      Founding BSCL2 families; not every allele is null.
  variants:
  - name: Biallelic BSCL2 pathogenic variants
    description: Null and missense BSCL2 variants disrupt seipin-dependent lipid-droplet regulation and adipocyte differentiation.
    gene:
      preferred_term: BSCL2
      term:
        id: hgnc:15832
        label: BSCL2
    clinical_significance: PATHOGENIC
    functional_effects:
    - function: Seipin lipid-droplet regulation
      description: Disrupts lipid-droplet organization and terminal adipocyte differentiation.
      type: loss-of-function
    evidence:
    - reference: PMID:22269949
      reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        In vitro differentiation of both Bscl2(-/-) murine embryonic fibroblasts (MEFs) and stromal vascular
        cells (SVCs) reveals normal early-phase adipocyte differentiation but a striking failure in terminal
        differentiation due to unbridled cyclic AMP (cAMP)-dependent protein kinase A (PKA)-activated lipolysis,
        which leads to loss of lipid droplets and silencing of the expression of adipose tissue-specific transcription
        factors.
      explanation: Cell-model evidence links seipin loss to lipid-droplet loss and adipocyte transcriptional silencing.
      directness: DIRECT
  notes: >-
    Recessive lipodystrophy-associated variants must be distinguished from heterozygous gain-of-function seipinopathy
    alleles causing motor neuropathy. Severe neurodegenerative BSCL2 presentations also require variant-specific
    interpretation.
- name: CAV1 pathogenic variants
  subtype: CGL3
  gene_term:
    preferred_term: CAV1
    term:
      id: hgnc:1527
      label: CAV1
  association: Causative biallelic pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:18211975
    reference_title: Association of a homozygous nonsense caveolin-1 mutation with Berardinelli-Seip congenital lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      RESULTS: A homozygous nonsense mutation (p.Glu38X) was identified in CAV1 in a patient with BSCL born
      from a consanguineous union.
    explanation: >-
      Original homozygous CAV1 nonsense variant; fibroblasts lack both caveolin-1 isoforms.
  - *id005
  - reference: PMID:34643546
    reference_title: Biallelic CAV1 null variants induce congenital generalized lipodystrophy with achalasia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Heterozygous parents and relatives (n = 9) were asymptomatic, without any metabolic abnormality.
    explanation: >-
      Observation limited to this family; other heterozygous CAV1 variants cause distinct disorders.
  variants:
  - name: CAV1 p.Glu38Ter
    type: Nonsense variant
    description: >-
      Homozygous truncating allele in the founding patient, with loss of both caveolin-1 isoforms in fibroblasts.
    evidence:
    - *id006
  - name: CAV1 p.His79GlnfsTer3
    type: Frameshift variant
    description: >-
      Homozygous frameshift in four related patients; nine heterozygous relatives in this family were clinically
      unaffected.
    evidence:
    - *id005
- name: CAVIN1 pathogenic variants
  subtype: CGL4
  gene_term:
    preferred_term: CAVIN1
    term:
      id: hgnc:9688
      label: CAVIN1
  association: Causative biallelic pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes
      suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate
      leading to the detection of homozygous mutations (c.160delG, c.362dupT).
    explanation: >-
      Primary CAVIN1 families.
  notes: >-
    Homozygous and compound heterozygous frameshift alleles are documented. An IVS1+1G>T allele was predicted
    to retain intronic sequence in the 2010 series; this predicted RNA consequence is not represented as an
    experimentally observed transcript.
  variants:
  - name: CAVIN1 c.160delG
    type: Frameshift variant
    description: >-
      Reported homozygous truncating allele in CGL4 families.
    evidence:
    - *id007
  - name: CAVIN1 c.362dupT
    type: Frameshift variant
    description: >-
      Reported homozygous truncating allele in the UK CGL4 patient.
    evidence:
    - reference: PMID:20300641
      reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Prioritization of 74 candidate genes with GeneDistiller for high expression in muscle and adipocytes
        suggested PTRF-CAVIN (Polymerase I and transcript release factor/Cavin) as the most probable candidate
        leading to the detection of homozygous mutations (c.160delG, c.362dupT).
      explanation: >-
        Primary variant observation.
- name: PPARG pathogenic variants
  subtype: CGL-PPARG
  gene_term:
    preferred_term: PPARG
    term:
      id: hgnc:9236
      label: PPARG
  association: Rare biallelic pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive
    description: >
      The generalized congenital presentation requires two PPARG variants. ClinGen
      curates PPARG-related lipodystrophy as semidominant overall, because the
      common presentation is autosomal dominant familial partial lipodystrophy and
      only the rare recessive cases are generalized and congenital.
    evidence:
    - reference: CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z
      reference_title: "PPARG / lipodystrophy (Definitive)"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "We have now curated the inheritance pattern for PPARG -related lipodystrophy as semidominant because, while most cases are autosomal dominant, very rarely a recessive mode of inheritance has been reported (Dyment et al, PMID:24980513; Gosseaume et al, PMID:36806620)."
      explanation: >-
        ClinGen's stated inheritance call, which is what makes the recessive
        generalized presentation a rare mode rather than the usual one.
  notes: >
    The index patient carried compound heterozygous PPARG variants c.413_416delAATG
    p.Glu138ValfsX168 and c.490C>T p.R164W. ClinGen's lumping decision keeps both
    PPARG diseases in a single gene-disease curation of lipodystrophy
    (MONDO:0006573) because the implicated variants overlap; dismech splits them by
    phenotype instead, with the dominant partial form on the Familial Partial
    Lipodystrophy entry and this recessive generalized form here.
  evidence:
  - reference: PMID:24980513
    reference_title: "Biallelic mutations at PPARG cause a congenital, generalized lipodystrophy similar to the Berardinelli-Seip syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "She showed the hallmark features of a congenital, generalized lipodystrophy (CGL)."
    explanation: >-
      The biallelic PPARG proband is reported as showing the hallmark features of
      congenital generalized lipodystrophy.
    directness: DIRECT
  - reference: CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z
    reference_title: "PPARG / lipodystrophy (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Specifically, PPARG has two associated diseases, namely the more commonly associated autosomal dominant familial partial lipodystrophy (OMIM:604367), and the more rarely associated autosomal recessive congenital, generalized lipodystrophy."
    explanation: >-
      ClinGen names the two PPARG diseases and assigns the autosomal recessive
      congenital generalized one, curated here, to the rarer of the two.
  - reference: CGGV:assertion_b4c76c1c-7e8a-418f-ba62-b7eeb3c3d472-2024-08-14T160000.000Z
    reference_title: "PPARG / lipodystrophy (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "with most cases presenting as familial partial lipodystrophy and two cases with congenital, generalized lipodystrophy"
    explanation: >-
      Quantifies how rare this presentation is: two congenital generalized cases
      among the probands ClinGen curated.
treatments:
- name: Metreleptin replacement therapy
  description: >-
    Metreleptin with diet is a first-line therapy for metabolic and endocrine complications of generalized
    lipodystrophy. The final NIH open-label analysis included 45 congenital and 21 acquired cases; congenital-group
    changes at 12 months/last observation were −1.8 percentage points in HbA1c and −22.2% in triglycerides.
    Published NIH cohorts overlap. Treatment improves metabolism without restoring absent fat; pooled liver
    and glycemic effects are not CGL-specific estimates.
  therapeutic_modality: PROTEIN_REPLACEMENT
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      In generalized lipodystrophy, metreleptin (with diet) is a first-line treatment for metabolic and endocrine
      abnormalities
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:29644599
    reference_title: Long-term effectiveness and safety of metreleptin in the treatment of patients with generalized lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      In the full analysis set, reductions in mean HbA1c and fasting TGs, respectively, from baseline to month
      12/LOCF were numerically greater in patients with acquired GL (−2.9% and −53.5%) than in patients with
      congenital GL (−1.8% and −22.2%).
    explanation: >-
      Subtype-specific analysis from an uncontrolled integrated study, including imputation; not a randomized
      CGL-only treatment effect.
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Acute pancreatitis due to hypertriglyceridemia has occurred in patients who acutely discontinued or reduced
      metreleptin (47).
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      To reduce the risk of hypoglycemia, frequent glucose monitoring is recommended.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:29644599
    reference_title: Long-term effectiveness and safety of metreleptin in the treatment of patients with generalized lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The US label for metreleptin carries a boxed warning that T-cell lymphoma has been reported in patients
      with acquired GL, in those both treated and untreated with metreleptin.
    explanation: >-
      Publication discusses the acquired-disease risk and causal uncertainty.
    quote_role: BACKGROUND
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: Metreleptin
      term:
        id: NCIT:C170171
        label: Metreleptin
  target_mechanisms:
  - target: Leptin deficiency
    treatment_effect: RESTORES
    description: >-
      Replacement of deficient leptin restores hormonal signaling without reversing the initiating adipose
      genetic defect.
    evidence:
    - reference: PMID:27710244
      reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        In generalized lipodystrophy, metreleptin (with diet) is a first-line treatment for metabolic and endocrine
        abnormalities
      explanation: >-
        Multi-society clinical guidance; evidence is often consensus-based.
      quote_role: REVIEW_SYNTHESIS
  notes: >-
    Monitor glucose closely and adjust insulin to avoid hypoglycemia. Avoid abrupt withdrawal because rebound
    hypertriglyceridemia and pancreatitis can occur. Loss of response may warrant assessment for neutralizing
    antibodies. Reported lymphoma risk is principally linked to acquired generalized lipodystrophy; these reports
    do not establish a CGL-specific causal lymphoma effect.
- name: Individualized nutritional management
  description: >-
    Use balanced macronutrients, restrict simple sugars and excessive fat, and preserve linear growth in children.
    Avoid overfeeding to achieve normal BMI because fat loss distorts body-composition targets. Very-low-fat
    intake is reserved for chylomicronemia-associated acute pancreatitis; infant feeding may require specialist
    medium-chain triglyceride formulations.
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Most patients should follow diets with balanced macronutrient composition.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Overfeeding to achieve normal weight may worsen metabolic complications and hepatic steatosis.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Very-low-fat diets should be used in chylomicronemia-induced acute pancreatitis.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Agents/circumstances to avoid: Excessive dietary fat intake.
    explanation: >-
      Historical GeneReviews advice is corroborated and qualified by the multi-society guideline.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Dietary Intervention
    term:
      id: NCIT:C15447
      label: Dietary Intervention
- name: Physical activity with cardiac and skeletal precautions
  description: >-
    Encourage activity after appropriate cardiac assessment. Avoid strenuous exercise in CGL4 and cardiomyopathy,
    and contact sports with severe organomegaly or lytic bone lesions.
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients with subtypes of lipodystrophy predisposed to cardiomyopathy should undergo cardiac evaluation
      before initiating an exercise regimen.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Contact sports should be avoided in patients with severe hepatosplenomegaly and CGL patients with lytic
      bone lesions.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients with type 4 CGL should avoid strenuous exercise and can be treated with β-adrenergic blockers
      and other anti-arrhythmic medications to prevent catecholaminergic polymorphic ventricular tachycardia.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Metformin
  description: >-
    Metformin is a first-line conventional agent for insulin resistance and diabetes, alongside diet and disease-directed
    leptin treatment when appropriate.
  therapeutic_modality: SMALL_MOLECULE
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Metformin is a first-line agent for diabetes and insulin resistance.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: metformin
      term:
        id: CHEBI:6801
        label: metformin
  target_mechanisms:
  - target: Severe insulin resistance
    treatment_effect: MODULATES
    description: >-
      Metformin is a first-line conventional agent for insulin resistance and diabetes, alongside diet and
      disease-directed leptin treatment when appropriate.
    evidence:
    - reference: PMID:27710244
      reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Metformin is a first-line agent for diabetes and insulin resistance.
      explanation: >-
        Multi-society clinical guidance; evidence is often consensus-based.
      quote_role: REVIEW_SYNTHESIS
- name: Insulin therapy
  description: >-
    Severe hyperglycemia can require high-dose or concentrated insulin. Injection-site selection and absorption
    need attention because subcutaneous fat is scarce; doses may fall substantially after metreleptin.
  therapeutic_modality: PEPTIDE
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Insulin is effective for hyperglycemia. In some patients, concentrated preparations and high-doses may
      be required.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: insulin
      term:
        id: CHEBI:145810
        label: insulin
- name: Triglyceride-lowering therapy
  description: >-
    Fibrates and long-chain omega-3 fatty acids are used for severe hypertriglyceridemia. Their use in lipodystrophy
    is supported mainly by clinical experience. Consider myopathy risk, particularly in CGL4.
  therapeutic_modality: SMALL_MOLECULE
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Fibrates and/or long-chain omega-3 fatty acids should be used for triglycerides >500 mg/dL and may be
      considered for triglycerides >200 mg/dL.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: omega-3 fatty acid
      term:
        id: CHEBI:25681
        label: omega-3 fatty acid
  target_mechanisms:
  - target: Circulating triglyceride excess
    treatment_effect: MODULATES
    description: >-
      Fibrates and long-chain omega-3 fatty acids are used for severe hypertriglyceridemia. Their use in lipodystrophy
      is supported mainly by clinical experience. Consider myopathy risk, particularly in CGL4.
    evidence:
    - reference: PMID:27710244
      reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: DIRECT
      snippet: >-
        Fibrates and/or long-chain omega-3 fatty acids should be used for triglycerides >500 mg/dL and may
        be considered for triglycerides >200 mg/dL.
      explanation: >-
        Multi-society clinical guidance; evidence is often consensus-based.
      quote_role: REVIEW_SYNTHESIS
- name: Statin therapy
  description: >-
    Statins address atherogenic cholesterol alongside lifestyle measures, with attention to age, reproductive
    status and muscular adverse effects.
  therapeutic_modality: SMALL_MOLECULE
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Statins should be used concomitantly with lifestyle modification (after consideration of age, reproductive
      status, and tolerance).
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Statins and fibrates should be used with caution due to increased risk of myopathy, especially in the
      presence of known myositis or muscular dystrophy (68).
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: statin
      term:
        id: CHEBI:87631
        label: statin
- name: CGL4 specialist arrhythmia management
  description: >-
    Specialist evaluation may include exercise-related rhythm assessment and beta-blockade. Nadolol was initiated
    in two affected siblings with exercise-induced polymorphic ventricular tachycardia; controlled efficacy
    was not reported. Implantable defibrillator or pacing decisions depend on individual risk.
  therapeutic_modality: SMALL_MOLECULE
  evidence:
  - reference: PMID:20684003
    reference_title: Congenital generalized lipodystrophy, type 4 (CGL4) associated with myopathy due to novel PTRF mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      She has been started on nadolol to treat this condition.
    explanation: >-
      Case-level treatment after exercise-induced polymorphic ventricular tachycardia; not an efficacy trial.
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Some patients with type 4 CGL might even benefit from an implantable pacemaker or defibrillator.
    explanation: >-
      Review recommendation requiring individualized electrophysiology assessment.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: Beta-Adrenergic Antagonist
      term:
        id: NCIT:C29576
        label: Beta-Adrenergic Antagonist
  target_phenotypes:
  - preferred_term: Arrhythmia
    term:
      id: HP:0011675
      label: Arrhythmia
- name: Metabolic, cardiac and renal surveillance
  description: >-
    Assess diabetes, triglycerides, liver enzymes, blood pressure and urine protein at least annually. Perform
    annual ECG and echocardiography in CGL. Obtain liver ultrasound at diagnosis and thereafter as indicated;
    assess puberty and reproductive symptoms. Complications or treatment changes require closer follow-up.
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Diabetes screening should be performed annually.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Electrocardiogram and echocardiogram should be performed annually in CGL and progeroid disorders, at
      diagnosis, and as clinically indicated in FPLD and AGL.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Urine protein should be measured annually using 24-hour urine collection or spot urine protein-to-creatinine
      ratio.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Liver ultrasound should be performed at diagnosis, then as clinically indicated.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      yearly echocardiogram; yearly or biennial liver ultrasound examination to detect fatty infiltration.
    explanation: >-
      Historical GeneReviews surveillance; current wording follows the more flexible liver-imaging schedule
      of the multi-society guideline.
    quote_role: REVIEW_SYNTHESIS
- name: Medication and reproductive precautions
  description: >-
    Avoid oral estrogen because of severe hypertriglyceridemia and pancreatitis risk. Consider nonhormonal
    or progestin-only contraception; use transdermal estrogen if replacement is needed. Avoid niacin, which
    can worsen insulin resistance. Thiazolidinedione benefits in partial lipodystrophy should not be transferred
    to CGL without caution.
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Oral estrogens are contraindicated in lipodystrophy syndromes due to the risk of severe hypertriglyceridemia
      and acute pancreatitis.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      If estrogen replacement is needed, transdermal estrogen should be used.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Niacin exacerbates insulin resistance and should be avoided.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Thiazolidinediones may improve metabolic complications in partial lipodystrophy but should only be used
      with caution in generalized lipodystrophy.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
- name: Specialist reproductive and pregnancy care
  description: >-
    Evaluate menstrual dysfunction and fertility, and coordinate high-risk pregnancy care for diabetes and
    triglycerides. Metreleptin continuation or withdrawal during pregnancy requires individualized specialist
    assessment because fetal data are limited and withdrawal may worsen metabolic disease.
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Pregnant patients should receive prenatal care from an obstetrician experienced in managing diabetes
      and a physician experienced in managing lipodystrophy.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
- name: Psychological and developmental support
  description: >-
    Offer support for distress, body-image concerns and stigma; provide educational support when intellectual
    impairment is present. Reconstructive consultation may be appropriate for functional or appearance concerns.
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:41713690
    reference_title: 'Clinical Guidelines for the Diagnosis and Management of Generalized and Partial Lipodystrophies: A Position Statement Endorsed by the Hellenic Endocrine Society.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Psychosocial support is essential due to the high burden of psychological distress and stigma.
    explanation: >-
      Current guideline position statement.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Special education might be necessary for individuals who also have an intellectual disability.
    explanation: >-
      Disease-specific clinical synthesis.
    quote_role: REVIEW_SYNTHESIS
- name: Genetic counseling and family testing
  description: >-
    Offer gene-specific recurrence counseling and testing of at-risk relatives. Discuss prenatal testing when
    familial variants are known. For PPARG, a single allele can cause partial lipodystrophy and should not
    automatically be treated as an asymptomatic carrier state.
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Carrier testing for at-risk relatives and prenatal testing for pregnancies at increased risk are possible
      if the pathogenic variants in the family are known.
    explanation: >-
      Historical chapter recommendation with PPARG-specific qualification.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
- name: Investigational mibavademab
  description: >-
    Mibavademab (REGN4461) is an investigational leptin-receptor agonist antibody. Generalized-lipodystrophy
    phase II and switch studies are completed, and phase III LAGO is recruiting as of the September 2026 registry
    update. Trial inclusion of congenital disease does not establish efficacy in every CGL genotype.
  therapeutic_modality: MONOCLONAL_ANTIBODY
  evidence:
  - reference: clinicaltrials:NCT06548100
    reference_title: A Single-Arm, Open-Label, Safety Study in Patients With Generalized Lipodystrophy Switching From Metreleptin to Mibavademab, A Leptin Receptor Agonist Antibody
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The aim of the study is to see how safe and tolerable mibavademab is when switching from treatment with
      metreleptin.
    explanation: >-
      Registry describes investigational use, not proven benefit.
  notes: >-
    The phase II registry has posted results. No results were posted for LAGO or the completed switch study
    at the October 2026 source check. Eligibility excludes certain significant cardiac conditions, so CGL4
    suitability requires protocol-specific assessment.
- name: Selected adjunctive diabetes therapies
  description: >-
    GLP-1 receptor agonists or SGLT2 inhibitors may be considered in selected patients by specialists. The
    2026 guideline discusses generalized and partial lipodystrophies together; it does not establish CGL-specific
    comparative efficacy.
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:41713690
    reference_title: 'Clinical Guidelines for the Diagnosis and Management of Generalized and Partial Lipodystrophies: A Position Statement Endorsed by the Hellenic Endocrine Society.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Adjunctive therapies, including glucagon-like peptide-1 receptor agonists and SGLT2 inhibitors, may offer
      additional metabolic benefit in selected cases.
    explanation: >-
      Guideline-level option across mixed lipodystrophy populations.
    quote_role: REVIEW_SYNTHESIS
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
diagnosis:
- name: Clinical lipodystrophy assessment
  diagnosis_term:
    preferred_term: disease screening
    term:
      id: NCIT:C15419
      label: Disease Screening
  description: >-
    Recognize near-generalized lack of body fat from birth or infancy with metabolic findings. Document onset
    and depot distribution using examination and, where useful, DXA or MRI. CGL4 fat loss may progress in infancy;
    lack of obvious neonatal lipoatrophy does not exclude it.
  results: Generalized lack of body fat with extreme muscularity supports CGL.
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients with CGL have near-complete lack of fat starting at birth or infancy.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
- name: CGL molecular genetic testing
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: NCIT:C15709
      label: Genetic Testing
  description: >-
    A phenotype-guided panel including AGPAT2, BSCL2, CAV1, CAVIN1 and rare PPARG presentations can define
    the molecular subtype. Negative testing does not exclude a genetic lipodystrophy; broader sequencing may
    be appropriate.
  results: Biallelic pathogenic variants in a known CGL gene support molecular diagnosis.
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Genotyping may include limited candidate gene sequencing, a panel of candidate genes, or whole-exome/whole-genome
      sequencing.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Because there is strong evidence for additional loci for genetic lipodystrophies, negative tests do not
      rule out a genetic condition.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
  - reference: PMID:20301391
    reference_title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The diagnosis of BSCL is established in a proband with three major criteria or two major criteria plus
      two or more minor criteria and/or by the identification of biallelic pathogenic variants in AGPAT2 or
      BSCL2.
    explanation: >-
      Historical diagnostic framework; the current panel extends beyond the two genes in this retired chapter.
    quote_role: REVIEW_SYNTHESIS
- name: Metabolic workup and leptin interpretation
  description: >-
    Assess glucose, insulin, triglycerides, liver disease and leptin in the clinical context. Low leptin supports
    the endocrine phenotype and treatment assessment but is not a stand-alone diagnostic cutoff.
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Because serum leptin assays are not standardized and leptin concentrations in patients with lipodystrophy
      (especially partial forms) overlap the general population, leptin levels do not help in diagnosis but
      may help with the choice of therapies.
    explanation: >-
      Multi-society clinical guidance; evidence is often consensus-based.
    quote_role: REVIEW_SYNTHESIS
references:
- reference: ORPHA:528
  title: Congenital generalized lipodystrophy
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:20301391
  title: Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
  tags:
  - GeneReviews
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:11967537
  title: AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:11479539
  title: Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13.
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:12362029
  title: Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy.
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:22269949
  title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:25734254
  title: "Partial and generalized lipodystrophy: comparison of baseline characteristics and response to metreleptin."
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:26239609
  title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
  found_in:
  - Berardinelli_Seip_Congenital_Lipodystrophy-deep-research-fallback.md
- reference: PMID:29723161
  title: "Metreleptin-mediated improvements in insulin sensitivity are independent of food intake in humans with lipodystrophy."
histopathology:
- name: CGL4 dystrophic muscle and reduced caveolae
  subtype: CGL4
  description: >-
    Skeletal muscle can show dystrophic changes, abnormal caveolin localization and sparse caveolae. The extent
    of fibrosis, necrosis and caveolin protein depletion differs between reported cohorts; reduced membrane
    organization is more consistent than universal loss of caveolin abundance.
  evidence:
  - reference: PMID:19726876
    reference_title: Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all 3
      caveolin family members, and reduction of caveolae structure.
    explanation: >-
      Direct muscle biopsy findings in the Japanese CGL4 cohort.
  - reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      PTRF-CAVIN protein was completely absent from fibroblasts and skeletal muscle, whereas the caveolin-1
      and caveolin-3 abundance was unchanged (Figure 4D and 4G).
    explanation: >-
      Contrasting protein abundance in a separate primary series.
- name: CGL4 intestinal smooth-muscle hypertrophy
  subtype: CGL4
  description: >-
    Massive smooth-muscle hypertrophy was demonstrated in a colonic specimen after ileus in one patient; this
    is not a finding measured in every case.
  evidence:
  - reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      At 12 years of age, an acute ileus after appendectomy required a partial bowel resection and histology
      of the colon wall revealed massive smooth muscle hypertrophy.
    explanation: >-
      Patient bowel histology.
experimental_models:
- name: CAVIN1-deficient patient fibroblasts
  experimental_model_type: PRIMARY_CELL_CULTURE
  cell_source: Patient-derived skin fibroblasts
  description: >-
    Patient fibroblasts had a greater than 97% reduction in caveolae. Wild-type CAVIN1 transfection restored
    peripheral punctate caveolar staining. The experiment supports cell-autonomous caveola formation, without
    demonstrating clinical rescue.
  modeled_mechanisms:
  - target: CAVIN1 caveola biogenesis defect
    relationship: RECAPITULATES
    model_scale: CELLULAR
    evidence:
    - &id008
      reference: PMID:20300641
      reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: DIRECT
      snippet: >-
        Morphometric analysis by transmission electron microscopy of the quantity of caveolae on the cell surface
        revealed a severe reduction by >97% in the patient's fibroblasts (Figure 7A and 7B).
      explanation: >-
        Patient fibroblast ultrastructure.
  evidence:
  - *id008
  - reference: PMID:20300641
    reference_title: Fatal cardiac arrhythmia and long-QT syndrome in a new form of congenital generalized lipodystrophy with muscle rippling (CGL4) due to PTRF-CAVIN mutations.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: >-
      However, transfection of a construct into patient fibroblasts, which contained the full-length, wild-type
      PTRF-CAVIN gene cloned downstream of the eukaryotic CMV-promoter, reconstituted the punctate staining
      pattern at the cell periphery that corresponds to the caveolae (Figure 6E–6G).
    explanation: >-
      Rescue in cultured cells, not a clinical gene-therapy intervention.
- name: CAV1-deficient patient fibroblasts
  experimental_model_type: PRIMARY_CELL_CULTURE
  cell_source: Skin fibroblasts from a new CGL3 index patient and the previously reported patient
  description: >-
    Fibroblasts lack caveolae and caveolin-1, caveolin-2 and cavin-1 protein expression, with impaired insulin
    responses, oxidative stress and premature senescence.
  modeled_mechanisms:
  - target: CAV1-dependent caveola loss
    relationship: RECAPITULATES
    model_scale: CELLULAR
    evidence:
    - *id009
  evidence:
  - reference: PMID:34643546
    reference_title: Biallelic CAV1 null variants induce congenital generalized lipodystrophy with achalasia.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: >-
      Patients' fibroblasts also displayed insulin resistance, increased oxidative stress, and premature senescence.
    explanation: >-
      Direct cultured patient-cell findings.
- name: Bscl2-deficient adipogenic cultures
  experimental_model_type: PRIMARY_CELL_CULTURE
  cell_source: Mouse embryonic fibroblasts and stromal vascular cells
  description: >-
    Knockout cultures retain early differentiation but fail terminal adipogenesis with excessive cAMP/PKA-dependent
    lipolysis. Lipolysis inhibitors largely rescue differentiation, whereas the tested PPARgamma agonist does
    not.
  modeled_mechanisms:
  - target: Unrestrained adipocyte lipolysis
    relationship: PARTIALLY_RECAPITULATES
    model_scale: CELLULAR
    evidence:
    - *id001
    limitations: >-
      Mouse-derived cells, not direct human adipocyte measurements.
  - target: Failure of terminal adipocyte differentiation
    relationship: PARTIALLY_RECAPITULATES
    model_scale: CELLULAR
    evidence:
    - *id001
    limitations: >-
      The model resolves a cell-level sequence rather than all human subtype effects.
  evidence:
  - reference: PMID:22269949
    reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: >-
      Importantly, such defects in differentiation can be largely rescued by inhibitors of lipolysis but not
      by a gamma peroxisome proliferator-activated receptor (PPARγ) agonist.
    explanation: >-
      Experimental rescue does not establish clinical efficacy of a lipolysis inhibitor.
animal_models:
- name: Bscl2 knockout mice
  species: Mus musculus
  genotype: Bscl2 homozygous knockout
  description: >-
    The model develops severe white-adipose lipodystrophy, insulin resistance and hepatic steatosis. Its fasting
    glucose and triglyceride behavior differs from human CGL2; reports of fasting reductions and postprandial
    hypertriglyceridemia should not be generalized to patients.
  modeled_mechanisms:
  - target: Generalized adipose tissue loss
    relationship: RECAPITULATES
    model_scale: TISSUE
    evidence:
    - reference: PMID:22269949
      reference_title: Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      directness: DIRECT
      snippet: >-
        Bscl2(-/-) mice develop severe lipodystrophy of white adipose tissue (WAT), dyslipidemia, insulin resistance,
        and hepatic steatosis.
      explanation: >-
        Primary knockout phenotype.
  evidence:
  - reference: PMID:26239609
    reference_title: Congenital generalized lipodystrophies--new insights into metabolic dysfunction.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    directness: DIRECT
    snippet: >-
      however, these mice have lower plasma levels glucose and triglyceride upon fasting than wild-type mice,
      but have postprandial hypertriglyceridaemia.
    explanation: >-
      Review synthesis of the model-specific metabolic limitation.
    quote_role: REVIEW_SYNTHESIS
clinical_trials:
- name: NCT00896298
  phase: PHASE_III
  status: COMPLETED
  description: >-
    Phase II/III Randomized leptin-versus-placebo study enrolling 25 participants with partial or generalized
    lipodystrophy. Results are posted; the mixed population is not a CGL-only efficacy estimate.
  notes: >-
    Status, design and population checked against the live ClinicalTrials.gov record on 2026-10-01.
  evidence:
  - reference: clinicaltrials:NCT00896298
    reference_title: Double-Blind, Placebo-Controlled Trial of Leptin Replacement Therapy in Patients With Lipodystrophy
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The purpose of the study is to examine the safety and efficacy of Leptin on subjects with lipodystrophy.
    explanation: >-
      Registry summary describes the study objective; recruitment and completion do not establish benefit.
- name: NCT04159415
  phase: PHASE_II
  status: COMPLETED
  description: >-
    Randomized sequential REGN4461 study in generalized lipodystrophy, with 16 actual participants and posted
    results. Congenital and acquired disease were eligible.
  notes: >-
    Status, design and population checked against the live ClinicalTrials.gov record on 2026-10-01.
  evidence:
  - reference: clinicaltrials:NCT04159415
    reference_title: A Randomized, Double-Blind, Placebo-Controlled Study of REGN4461, a Leptin Receptor Agonist Antibody, in Patients With Generalized Lipodystrophy
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The primary objectives of the study are to estimate the effects of REGN4461 on glycemic parameters in
      the subset of patients with elevated baseline hemoglobin A1c levels (HbA1c ≥7%) and to estimate the effects
      of REGN4461 on fasting triglyceride levels in the subset of patients with elevated baseline fasting triglycerides
      (TG ≥250 mg/dL).
    explanation: >-
      Registry summary describes the study objective; recruitment and completion do not establish benefit.
- name: NCT07220785
  phase: PHASE_III
  status: RECRUITING
  description: >-
    LAGO randomized phase III study of mibavademab in congenital or acquired generalized lipodystrophy. Part
    A tests efficacy and Part B pediatric safety/pharmacokinetics. Planned enrollment is 28; no results are
    posted.
  notes: >-
    Status, design and population checked against the live ClinicalTrials.gov record on 2026-10-01.
  evidence:
  - reference: clinicaltrials:NCT07220785
    reference_title: A Two-Part, Randomized, Placebo-Controlled Phase 3 Study of the Efficacy, Safety, and Pharmacokinetics of Mibavademab in Patients With Generalized Lipodystrophy (LAGO)
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      This is a 2-part study: Part A is an efficacy study in pediatric and adult participants, Part B is a
      safety and pharmacokinetic study in pediatric participants.
    explanation: >-
      Registry summary describes the study objective; recruitment and completion do not establish benefit.
- name: NCT06548100
  phase: PHASE_III
  status: COMPLETED
  description: >-
    Single-arm study of nine participants switching from metreleptin to mibavademab after at least six months
    of metreleptin. No results were posted at the source check.
  notes: >-
    Status, design and population checked against the live ClinicalTrials.gov record on 2026-10-01.
  evidence:
  - reference: clinicaltrials:NCT06548100
    reference_title: A Single-Arm, Open-Label, Safety Study in Patients With Generalized Lipodystrophy Switching From Metreleptin to Mibavademab, A Leptin Receptor Agonist Antibody
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The aim of the study is to see how safe and tolerable mibavademab is when switching from treatment with
      metreleptin.
    explanation: >-
      Registry summary describes the study objective; recruitment and completion do not establish benefit.
- name: NCT06502990
  phase: PHASE_III
  status: TERMINATED
  description: >-
    Metreleptin study in children under six with generalized lipodystrophy and diabetes and/or hypertriglyceridemia.
    One participant enrolled; the registry states closure because the study was no longer an EMA requirement,
    not because of demonstrated toxicity.
  notes: >-
    Status, design and population checked against the live ClinicalTrials.gov record on 2026-10-01.
  evidence:
  - reference: clinicaltrials:NCT06502990
    reference_title: Open-label, Phase 3b Study to Evaluate Effectiveness, Safety and Pharmacokinetic Parameters of Metreleptin in Patients Under 6 Years of Age With Generalised Lipodystrophy and Associated Diabetes Mellitus and/or Hypertriglyceridaemia
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      This is an open-label, Phase 3b study to evaluate effectiveness, safety and pharmacokinetic parameters
      of metreleptin in patients under 6 years of age with generalised lipodystrophy and associated diabetes
      mellitus and/or hypertriglyceridaemia
    explanation: >-
      Registry summary describes the study objective; recruitment and completion do not establish benefit.
- name: NCT02325674
  phase: NOT_APPLICABLE
  status: RECRUITING
  description: >-
    MEASuRE observational postauthorization registry follows metreleptin-treated patients for long-term safety
    and effectiveness. Includes US generalized disease and European generalized or partial disease; not a randomized
    treatment trial.
  notes: >-
    Status, design and population checked against the live ClinicalTrials.gov record on 2026-10-01.
  evidence:
  - reference: clinicaltrials:NCT02325674
    reference_title: 'MEASuRE: Metreleptin Effectiveness And Safety Registry'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      The study is a post-authorization, prospective, voluntary registry of patients treated with commercial
      metreleptin including, but not limited to, patients in the US and EEA.
    explanation: >-
      Registry summary describes the study objective; recruitment and completion do not establish benefit.
differential_diagnoses:
- name: PCYT1A-related lipodystrophy with hepatic steatosis
  description: >-
    Biallelic PCYT1A deficiency is a related phosphatidylcholine-synthesis disorder. Two reported patients
    had severe hepatic disease and lipodystrophy, but one developed progressive limb fat loss at nine years,
    and neither showed the skeletal/retinal syndrome seen with other PCYT1A variants. This broader presentation
    is a diagnostic consideration rather than an additional numbered classical CGL subtype.
  distinguishing_features:
  - Severe early hepatic steatosis can precede progressive limb fat loss.
  - Short stature without the typical marked muscularity; phenotype varies across the PCYT1A spectrum.
  evidence:
  - reference: PMID:24889630
    reference_title: Mutations disrupting the Kennedy phosphatidylcholine pathway in humans with congenital lipodystrophy and fatty liver disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      At age 9 y, progressive limb fat loss developed.
    explanation: >-
      Patient 2 does not have the classic neonatal generalized fat-loss chronology.
  - reference: PMID:24889630
    reference_title: Mutations disrupting the Kennedy phosphatidylcholine pathway in humans with congenital lipodystrophy and fatty liver disease.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Her retinal assessment was normal and the skeletal survey did not reveal any features of spondylometaphyseal
      dysplasia.
    explanation: >-
      Patient 1 was reassessed after recognition of the separate PCYT1A skeletal-retinal phenotype.
- name: Familial Partial Lipodystrophy
  description: >-
    Partial inherited lipodystrophy typically preserves or increases fat in some depots. PPARG monoallelic
    disease usually belongs to this spectrum; rare biallelic CGL-like cases are represented here with explicit
    scope qualifications.
  distinguishing_features:
  - Regional rather than near-total fat loss, often apparent around puberty.
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Patients with FPLD have fat loss of the extremities typically occurring around puberty and can have a
      positive family history.
    explanation: >-
      Clinical diagnostic distinction.
    quote_role: REVIEW_SYNTHESIS
- name: Acquired generalized lipodystrophy
  description: >-
    Acquired disease often develops after an interval of normal fat distribution and may be associated with
    autoimmunity. Early infancy onset can occasionally complicate the distinction.
  distinguishing_features:
  - Prior normal fat distribution and associated autoimmunity favor acquired disease.
  evidence:
  - reference: PMID:27710244
    reference_title: 'The Diagnosis and Management of Lipodystrophy Syndromes: A Multi-Society Practice Guideline.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: >-
      Review of photographs from infancy may distinguish CGL from AGL because infants typically show absent
      fat in CGL and normal fat in AGL.
    explanation: >-
      Clinical distinction is useful but not absolute.
    quote_role: REVIEW_SYNTHESIS

📚

References & Deep Research

References

9

ORPHA:528

Congenital generalized lipodystrophy

No top-level findings curated for this source.

PMID:20301391

Berardinelli-Seip Congenital Lipodystrophy – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.

No top-level findings curated for this source.

PMID:11967537

AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.

No top-level findings curated for this source.

PMID:11479539

Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13.

No top-level findings curated for this source.

PMID:12362029

Genotype-phenotype relationships in Berardinelli-Seip congenital lipodystrophy.

No top-level findings curated for this source.

PMID:22269949

Berardinelli-seip congenital lipodystrophy 2/seipin is a cell-autonomous regulator of lipolysis essential for adipocyte differentiation.

No top-level findings curated for this source.

PMID:25734254

Partial and generalized lipodystrophy: comparison of baseline characteristics and response to metreleptin.

No top-level findings curated for this source.

PMID:26239609

Congenital generalized lipodystrophies--new insights into metabolic dysfunction.

No top-level findings curated for this source.

PMID:29723161

Metreleptin-mediated improvements in insulin sensitivity are independent of food intake in humans with lipodystrophy.

No top-level findings curated for this source.

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Berardinelli-Seip Congenital Lipodystrophy Deep Research Fallback ▸

Berardinelli-Seip Congenital Lipodystrophy Deep Research Fallback

Date: 2026-05-04T12:09Z

Provider Attempts

timeout 120 just research-disorder falcon Berardinelli_Seip_Congenital_Lipodystrophy
Result: timed out after the bounded 120-second run and was terminated by signal 15.
Completed artifact: none.
timeout 120 just research-disorder openai Berardinelli_Seip_Congenital_Lipodystrophy
Result: timed out after the bounded 120-second run and was terminated by signal 15.
Completed artifact: none.

No provider-generated deep-research narrative was available within the bounded runtime. Curation therefore proceeded from regenerated structured Orphanet evidence and fetched PubMed caches, without hand-editing any references_cache/*.md files.

Evidence Scope Used For Curation

Structured Source

ORPHA:528 congenital generalized lipodystrophy structured record
Exact MONDO cross-reference: MONDO:0018883
Inheritance: autosomal recessive
Natural history: neonatal, infantile, and childhood onset categories
Worldwide point-prevalence band: 1-9 / 1 000 000
Frequent or very frequent HPO phenotypes integrated in the YAML: insulin resistance, hepatomegaly, skeletal muscle hypertrophy, adipose tissue loss, lipodystrophy, diabetes mellitus, hypertrichosis, intellectual disability, and hypertriglyceridemia
Additional ORPHA phenotypes integrated where mechanistically relevant: hepatic steatosis, acanthosis nigricans, hypertrophic cardiomyopathy, and hyperinsulinemia
Cross-references include OMIM 269700, 608594, 612526, and 613327, used to label the four molecular subtype descriptions.

PubMed Records

PMID:11967537 Agarwal et al. 2002
Identifies AGPAT2 mutations in congenital generalized lipodystrophy linked to 9q34.
Supports autosomal recessive inheritance, marked adipose tissue paucity, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis, early diabetes, and impaired triacylglycerol synthesis/storage in adipocytes.
PMID:11479539 Magre et al. 2001
Identifies the chromosome 11q13 BSCL2/seipin disease gene in Berardinelli-Seip congenital lipodystrophy families.
Supports severe disruption of seipin and clinical features including acanthosis nigricans, hepatomegaly, diabetes, muscle hypertrophy, and hypertriglyceridemia.
PMID:12362029 Van Maldergem et al. 2002
Cohort genotype-phenotype analysis of 70 affected subjects.
Supports BSCL2-associated higher prevalence of intellectual impairment, molecular diagnosis, genetic counseling implications, hepatic dysfunction, hyperlipidemia, diabetes, hypertrophic cardiomyopathy, and subtype severity differences.
PMID:22269949 Chen et al. 2012
Bscl2 knockout mouse and cell differentiation study.
Supports severe white-adipose lipodystrophy, dyslipidemia, insulin resistance, hepatic steatosis, failure of terminal adipocyte differentiation, lipid-droplet loss, and activated lipolysis mechanisms.
PMID:25734254 Diker-Cohen et al. 2015
Prospective, single-arm, open-label metreleptin study in generalized and partial lipodystrophy.
Supports metreleptin use in generalized lipodystrophy and reductions in HbA1c and triglycerides.
PMID:26239609 Patni and Garg 2015
Full-text review of congenital generalized lipodystrophy pathophysiology and treatment.
Supports the four subtype genes AGPAT2, BSCL2, CAV1, and PTRF/CAVIN1; convergence on phospholipid/triglyceride synthesis, lipid droplets, and caveolae; ectopic triglyceride accumulation in liver and skeletal muscle; severe hypoleptinemia; dietary management; conventional diabetes and lipid therapy; and metreleptin replacement.

Curation Conclusions

The curated mechanism model treats Berardinelli-Seip congenital lipodystrophy as a genetically heterogeneous but convergent adipocyte lipid-storage disorder. AGPAT2 deficiency impairs phosphatidic acid production for triglyceride and glycerophospholipid synthesis. BSCL2/seipin deficiency disrupts lipid-droplet organization and terminal adipocyte differentiation. CAV1 and CAVIN1/PTRF defects impair caveola structure or biogenesis, reducing adipocyte lipid handling and expandability. These upstream defects cause generalized adipose tissue loss. The inability to store triglyceride in adipose tissue diverts lipid to liver and skeletal muscle, producing hepatic steatosis, hypertriglyceridemia, hepatomegaly, and severe insulin resistance. Near-total adipose loss also causes hypoleptinemia, worsening hyperphagia and metabolic derangement.

Management is metabolic and supportive: metreleptin replacement addresses leptin-deficiency-driven metabolic complications in generalized lipodystrophy; low-fat dietary management aims to reduce triglyceride burden; conventional diabetes and hyperlipidemia therapy treats downstream complications; and genetic counseling is warranted for autosomal recessive recurrence risk and subtype-specific prognosis.

Berardinelli-Seip Congenital Lipodystrophy

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Phenotypes

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Diagnosis

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Differential Diagnoses

Clinical Trials

Experimental Models

Animal Models

Source YAML

References & Deep Research

References

Deep Research

Berardinelli-Seip Congenital Lipodystrophy Deep Research Fallback

Provider Attempts

Evidence Scope Used For Curation

Structured Source

PubMed Records

Curation Conclusions