Chylomicron Retention Disease: Disease-Characteristics Research Report

Executive summary

Chylomicron retention disease (CRD), or Anderson disease, is an ultra-rare, usually infancy-onset Mendelian disorder in which biallelic pathogenic variants in SAR1B impair COPII-dependent export of pre-chylomicrons from the enterocyte endoplasmic reticulum (ER) to the Golgi. Dietary lipid consequently accumulates within enterocytes, postprandial chylomicrons and apolipoprotein B-48 are absent or markedly reduced, and patients develop fat malabsorption, diarrhea, steatorrhea, growth failure, hypocholesterolemia, and fat-soluble-vitamin deficiency. Lifelong dietary and vitamin treatment usually controls gastrointestinal disease and substantially reduces irreversible neurologic, retinal, skeletal, muscular, and cardiac complications, but it does not correct the underlying trafficking defect. Evidence remains dominated by case reports, small cohorts, cell systems, and engineered animals; there are no randomized therapeutic trials or validated survival estimates.

The following table summarizes the principal knowledge-base fields.

Table: Compact evidence table summarizing the identity, phenotype frequencies, diagnostic signature, molecular mechanism, genetics, management, models, and prognosis of chylomicron retention disease. Evidence types and suggested ontology concepts are included for knowledge-base annotation.

1. Disease information

Definition and identifiers

CRD is a hereditary disorder of intestinal chylomicron secretion and lipid absorption. Its characteristic biochemical combination is low total cholesterol, LDL cholesterol, and HDL cholesterol, generally normal fasting triglycerides, and absent postprandial chylomicrons/apoB-48. It is distinct from defects that prevent apoB-lipoprotein assembly altogether because circulating LDL and apoB-100 remain detectable, albeit reduced (georges2011molecularanalysisand pages 1-2, peretti2018lessonsfromchylomicron pages 1-3).

Key identifiers and terminology

• MONDO: MONDO:0009528.
• OMIM phenotype: commonly catalogued as chylomicron retention disease, MIM 246700. Some older literature used MIM 607689; this inconsistency reflects historical nomenclature and should be checked against the current OMIM release before database ingestion.
• Causal gene: SAR1B, OMIM 607690; Ensembl ENSG00000152700; former symbol SARA2*; approved name “secretion associated Ras-related GTPase 1B” (OpenTargets Search: chylomicron retention disease-SAR1B, georges2011molecularanalysisand pages 1-2).
• Synonyms: Anderson disease, Anderson’s disease, chylomicron retention disease, chylomicron-retention disease, intestinal hypobetalipoproteinemia, and historically “Anderson syndrome.”
• Orphanet: the disease is represented in Orphanet, but an ORPHA number was not independently verified in the retrieved evidence.
• ICD/MeSH: no CRD-specific ICD-10 or ICD-11 code was demonstrated in the retrieved literature. Coding generally falls under broader disorders of lipoprotein metabolism or intestinal malabsorption. A dedicated MeSH descriptor was likewise not established here; “Lipid Metabolism, Inborn Errors” and “Malabsorption Syndromes” are appropriate indexing concepts.

The evidence in this report is principally aggregated disease-level evidence from published cohorts, reviews, molecular studies, and disease databases. It is not an analysis of individual electronic health records.

2. Etiology, risk, protective factors, and gene–environment interaction

Primary cause

The canonical cause is germline biallelic loss-of-function or function-disrupting variation in SAR1B, inherited autosomal recessively. Open Targets identifies SAR1B as the sole strongly supported target associated with MONDO:0009528 and links the association to human publications including PMID 12692552, 18786134, 19274794, and 21235735 (OpenTargets Search: chylomicron retention disease-SAR1B).

Rare phenocopies or unresolved cases exist. A Japanese patient with the clinical and histologic phenotype had maternal uniparental disomy of chromosome 7 and a normal SAR1B coding sequence, suggesting that regulatory defects or another lipid-export gene may occasionally produce a CRD-like phenotype. This does not overturn SAR1B as the established cause of typical CRD (georges2011molecularanalysisand pages 1-2).

Risk factors

• Genetic: two pathogenic SAR1B alleles; parental consanguinity increases the probability of homozygosity. Family history may be absent because heterozygotes generally have normal lipid profiles.
• Environmental/lifestyle: environmental exposure does not initiate the Mendelian disease. A high intake of long-chain triglycerides increases steatorrhea and enterocyte lipid loading; diarrhea commonly recurs when fat is reintroduced (peretti2018lessonsfromchylomicron pages 3-4, peretti2010guidelinesforthe pages 3-4).
• Age and sex: onset is usually during the first six months. No convincing human sex bias is established.
• Infectious/toxic/occupational factors: none established.

Protective factors

No protective SAR1B allele has been validated. Clinically protective measures are early recognition, restriction of long-chain dietary fat, adequate essential fatty acids and calories, and high-dose fat-soluble vitamins—particularly vitamin E. Early therapy was associated with absence of clinical or electrophysiologic neuro-ophthalmologic disease in 12 of 16 patients in the principal two-center experience (peretti2010guidelinesforthe pages 9-10).

Gene–environment interaction

Diet alters phenotype severity rather than disease occurrence. In Sar1b-mutant mice, an eight-week diet containing 60% fat exposed genotype- and sex-dependent changes in weight, adiposity, insulin resistance, hepatic steatosis, fatty-acid composition, cholesterol regulation, and intestinal ER stress. Female mice were relatively protected, but this sex effect remains a model-organism observation and should not be assumed in humans (levy2024unravelingchylomicronretention pages 10-12, auclair2023highfatdietreveals pages 11-13, auclair2023highfatdietreveals pages 9-10).

3. Phenotypes

The most useful frequency data derive from a literature synthesis and molecularly confirmed cohort of 16 patients, not a population registry. Therefore, estimates are susceptible to ascertainment and small-sample bias.

These frequencies are supported by the 16-patient synthesis: diarrhea 100%, steatorrhea 85%, growth failure 80%, distension 65%, vomiting and high CK 60%, vitamin E deficiency 95%, and low LDL/HDL 100% (peretti2010guidelinesforthe pages 3-4). Quality-of-life instruments such as EQ-5D, SF-36, or PROMIS have not been validated in CRD. Likely burdens include dietary restriction, recurrent gastrointestinal symptoms, frequent biochemical surveillance, impaired childhood growth, and preventable neurologic disability.

4. Genetic and molecular information

Gene and protein

SAR1B lies at 5q31.1, contains eight exons, and has predicted alternative exon-2 splicing. It encodes a 198-amino-acid Ras/ARF-family small GTPase. Human SAR1A and SAR1B differ at only 20 residues, but SAR1B binds SEC23 more strongly, has distinct GTPase-exchange kinetics, and is particularly important for intestinal chylomicron export (georges2011molecularanalysisand pages 1-2, tang2023cargoselectionin pages 2-3).

Representative pathogenic variants

Reported disease alleles include:

• Frameshift: p.Leu28Argfs*7, p.Asp48Thrfs*17, and c.83_84delTG (p.Leu28Argfs*7).
• Nonsense: p.Glu122*.
• Deletion: whole exon 2 deletion, functionally described as p.Met1_His43del.
• Missense: p.Asp137Asn, p.Ser179Arg, and p.Gly185Val (charcosset2008andersonorchylomicron pages 1-2, georges2011molecularanalysisand pages 1-2, charcosset2008andersonorchylomicron pages 8-9).

Frameshift/nonsense/deletion alleles generally produce absent or severely truncated proteins and are mechanistically loss-of-function. Missense substitutions can disrupt GTP binding/hydrolysis, SEC12 activation, SEC23 interaction, membrane association, or coat dynamics. The variants are germline, not somatic. The retrieved literature did not provide current gnomAD frequencies or a complete ClinVar classification table; each variant should therefore be rechecked in current ClinVar/gnomAD before assigning an ACMG class.

Expressivity, modifiers, and other genomic mechanisms

Clinical severity varies even among families carrying variants predicted to cause severe dysfunction, so a simple genotype–phenotype correlation is not established. Intestinal SAR1A rises approximately 1.4–2.7-fold in affected biopsies but does not compensate for a roughly two-thirds reduction in SAR1B. A co-occurring PCSK9 p.Leu21dup allele had no demonstrable additional effect. APOB, MTTP, ABCG5/ABCG8, transcriptional regulators, and dietary exposure are candidate modifiers, but none is validated as a CRD modifier (georges2011molecularanalysisand pages 8-11, georges2011molecularanalysisand pages 1-2, charcosset2008andersonorchylomicron pages 8-9).

No reproducible disease-specific DNA methylation, histone, chromatin, repeat-expansion, mitochondrial-DNA, or large chromosomal-abnormality mechanism is established. The chromosome-7 uniparental-disomy case is exceptional rather than the canonical mechanism.

5. Environmental information

CRD is not caused by toxins, radiation, pollution, smoking, alcohol, occupation, or infection. Dietary long-chain triglyceride is the most important phenotype-modifying exposure. Medium-chain triglycerides bypass chylomicron packaging to a greater extent and can provide calories, although their routine amount must be individualized. Excessively strict fat avoidance can worsen essential-fatty-acid deficiency; treatment therefore balances symptom control against growth and omega-3/omega-6 requirements (peretti2010guidelinesforthe pages 10-11, peretti2010guidelinesforthe pages 1-3).

6. Mechanism and pathophysiology

Ordered causal chain

1. Biallelic SAR1B pathogenic variants lead to reduced or dysfunctional SAR1B GTPase in absorptive small-intestinal enterocytes.
2. Defective SEC12-mediated nucleotide exchange or abnormal GTP hydrolysis/membrane interaction leads to impaired SAR1B cycling between GDP-bound inactive and GTP-bound active states.
3. Abnormal active SAR1B leads to defective recruitment or dynamics of the SEC23–SEC24 inner COPII coat and SEC13–SEC31 outer coat at ER exit sites.
4. Defective COPII assembly/scission and/or pre-chylomicron-vesicle fusion with Golgi leads to failed ER-to-Golgi export of unusually large apoB-48-containing pre-chylomicrons.
5. Failed export leads to intracellular retention of triglyceride-rich droplets and membrane-bound chylomicron-like particles in villus enterocytes.
6. Enterocyte retention leads to absent postprandial chylomicrons, reduced delivery of dietary triglyceride, cholesterol, essential fatty acids, and fat-soluble vitamins to blood and peripheral tissues.
7. Reduced lipid export leads to steatorrhea, chronic diarrhea, abdominal distension, hypocholesterolemia, low HDL, malnutrition, and growth failure.
8. Chronic vitamin E/essential-fatty-acid deficiency leads to neurologic, retinal, muscular, hematologic, and skeletal complications.
9. Branch—intracellular lipid accumulation probably leads to lipid peroxidation, ER stress, and inflammatory signaling; this branch is demonstrated in cell/animal models but remains incompletely validated as a driver of human complications.
10. Branch—SAR1B expression in liver and muscle may lead to hepatic, skeletal-muscle, and cardiac manifestations when function is severely impaired; extra-intestinal causality is supported but less firmly characterized than the enterocyte defect (levy2024unravelingchylomicronretention pages 10-12, georges2011molecularanalysisand pages 11-12, tang2023cargoselectionin pages 2-3, levy2024unravelingchylomicronretention pages 7-9).

Cellular and biochemical detail

SEC12 activates SAR1B at the ER membrane. SAR1B-GTP inserts an amphipathic helix, deforms the membrane, recruits SEC23/SEC24 and subsequently SEC13/SEC31, and helps generate and uncoat COPII carriers. SEC23/SEC31 stimulate GTP hydrolysis, allowing coat disassembly. Disruption at either nucleotide exchange or hydrolysis can therefore block secretion (georges2011molecularanalysisand pages 11-12, levy2024unravelingchylomicronretention pages 7-9).

In healthy duodenum, Sar1 protein is concentrated apically in enterocytes of the upper two-thirds of villi. CRD biopsies show reduced, heterogeneous Sar1 staining around large lipid droplets. SAR1B normally exceeds SAR1A expression approximately 2.5–3-fold in intestine (georges2011molecularanalysisand pages 8-11).

Suggested GO terms: ER-to-Golgi vesicle-mediated transport (GO:0006888); COPII-coated vesicle budding; GTPase activity; lipid transport; chylomicron assembly; cholesterol efflux; response to ER stress; response to oxidative stress. Suggested CL term: absorptive intestinal epithelial cell/enterocyte. Relevant pathways include Reactome COPII-mediated vesicle transport and intestinal lipoprotein assembly; canonical Wnt, MAPK, mTOR, and PI3K–AKT dysregulation are not established primary mechanisms.

Molecular profiling and advanced technologies

Patient-biopsy RT-qPCR demonstrated reduced SAR1B and compensatory but inadequate SAR1A expression. Caco-2/15 CRISPR disruption reduced chylomicron output and HDL biogenesis/cholesterol efflux; complete suppression of chylomicron secretion required combined SAR1A/SAR1B disruption, demonstrating paralog redundancy. Increased malondialdehyde supported lipid peroxidation (sane2017understandingchylomicronretention pages 9-10, levy2024unravelingchylomicronretention pages 10-12).

Recent work has integrated lipid profiles, fatty-acid composition, expression of PCSK9/LDLR, NPC1L1, SCARB1, ABCG8, MTTP, HMGCR, SREBP2, ABCA1, and LXRα, and ER-stress markers PERK, IRE1, GRP78, and ATF6 in engineered mice. No disease-specific human single-cell or spatial-transcriptomic atlas, validated proteomic signature, or clinical multi-omics classifier was identified (levy2024unravelingchylomicronretention pages 10-12, auclair2023highfatdietreveals pages 9-10).

7. Anatomical structures affected

• Primary organ/system: proximal small intestine and digestive system.
• Tissue/cell: villus epithelium, especially mature absorptive enterocytes. Suggested terms: UBERON “duodenum,” “jejunum,” “small intestine,” “intestinal villus”; CL “enterocyte.”
• Subcellular sites: ER membrane/ER exit sites, COPII-coated transport carriers, pre-chylomicron transport vesicles, Golgi apparatus, and cytoplasmic lipid droplets. Suggested GO-CC terms: endoplasmic reticulum membrane, ER exit site, COPII-coated ER-to-Golgi transport vesicle, Golgi apparatus, lipid droplet.
• Secondary organs: liver (steatosis/cytolysis), skeletal muscle (high CK/myopathy), peripheral nervous system, retina, skeleton, and occasionally heart.
• Localization/lateralization: diffuse intestinal involvement; no meaningful unilateral or bilateral pattern (peretti2018lessonsfromchylomicron pages 1-3, georges2011molecularanalysisand pages 8-11).

8. Temporal development

Symptoms usually begin chronically or insidiously between one and six months, sometimes neonatally. Only about one-third of reported children in an older synthesis were diagnosed during the first year, illustrating diagnostic delay (peretti2010guidelinesforthe pages 3-4, peretti2018lessonsfromchylomicron pages 1-3).

Early disease consists of diarrhea, steatorrhea, vomiting/distension, and faltering growth. Intermediate disease includes persistent biochemical deficiencies, delayed growth or puberty, hepatic cytolysis/steatosis, and elevated CK. Advanced untreated disease may include neuropathy, areflexia, ataxia, myopathy, retinal disease, poor bone mineralization, and cardiomyopathy. CRD is lifelong: gastrointestinal symptoms improve within days or weeks of fat restriction, but there is no reliable remission or intestinal adaptation, and steatorrhea persisted after approximately five years of observation (peretti2018lessonsfromchylomicron pages 3-4, peretti2010guidelinesforthe pages 3-4, peretti2010guidelinesforthe pages 1-3).

Infancy and early childhood are critical intervention windows because malnutrition affects growth and prolonged vitamin E deficiency may cause irreversible neuro-retinal injury.

9. Inheritance and population

CRD is autosomal recessive. For two confirmed carrier parents, each pregnancy has the conventional 25% affected, 50% carrier, and 25% unaffected/non-carrier probabilities. Heterozygotes are generally clinically and biochemically normal. Penetrance of clearly pathogenic biallelic variants appears high, but formal age-dependent penetrance estimates do not exist; expressivity is variable (charcosset2008andersonorchylomicron pages 1-2, peretti2018lessonsfromchylomicron pages 1-3).

Estimated prevalence is <1 per 1,000,000. Approximately 60 patients, about 40 genotyped and carrying roughly 20 different mutations, had been reported by 2018; underdiagnosis is likely. Published families include French-Canadian, Turkish, Algerian, Portuguese, European, Japanese, and other ancestries. Founder effects have been suggested in clustered families but no global carrier frequency or robust incidence estimate is available. Both sexes are affected. Consanguinity is a recognized enrichment mechanism; anticipation and germline mosaicism are not characteristic (charcosset2008andersonorchylomicron pages 1-2, peretti2018lessonsfromchylomicron pages 1-3, georges2011molecularanalysisand pages 1-2).

10. Diagnostics

Practical diagnostic pathway

1. In an infant or child with chronic diarrhea, steatorrhea, or unexplained growth failure, measure fasting total cholesterol, LDL-C, HDL-C, triglycerides, apoB, vitamins A/D/E/K, INR, liver enzymes, CK, blood count, iron, and essential-fatty-acid profile.
2. Suspect CRD when total/LDL cholesterol is approximately 50% of normal, HDL is low, triglycerides remain normal, and vitamin E is markedly low.
3. Demonstrate absent or markedly reduced postprandial chylomicrons/apoB-48 after a supervised fat load where clinically safe. A negative fat load was reported in 100% of summarized genotyped cases.
4. Upper endoscopy after dietary fat exposure may show a white or stippled duodenal/jejunal mucosa.
5. Biopsy shows preserved villus architecture but lipid-distended enterocytes, large cytoplasmic droplets, and membrane-bound lipoprotein-sized particles.
6. Confirm with sequencing and deletion/duplication analysis of SAR1B; test parents for phase and enable cascade screening (georges2011molecularanalysisand pages 1-2, peretti2018lessonsfromchylomicron pages 1-3, ferreira2018chylomicronretentiondisease pages 6-7).

A representative abstract states: “The diagnosis is based on a history of chronic diarrhea with fat malabsorption and abnormal lipid profile. Upper endoscopy and histology reveal fat-laden enterocytes whereas vitamin E deficiency is invariably present” (Peretti et al., published 22 September 2010; DOI 10.1186/1750-1172-5-24) (peretti2010guidelinesforthe pages 1-3).

Genetic-test selection

A hypocholesterolemia/fat-malabsorption panel should include at least SAR1B, MTTP, APOB, and often ANGPTL3, PCSK9, and other lipid genes. Single-gene SAR1B testing is efficient with a classic phenotype. WES/WGS is appropriate when panel testing is negative, the phenotype is syndromic, or regulatory/structural variation is suspected. Copy-number analysis is necessary because exon deletions occur. CMA, karyotyping, FISH, mitochondrial-DNA testing, and repeat-expansion assays are not first-line unless other clinical findings indicate them. RNA sequencing may clarify splice or regulatory variants but is not a routine validated diagnostic assay.

Differential diagnosis

• Abetalipoproteinemia (MTTP): nearly absent apoB-containing lipoproteins, extremely low LDL and triglycerides, prominent acanthocytosis; CRD retains apoB-100/LDL and usually has normal triglycerides.
• Biallelic APOB familial hypobetalipoproteinemia: severe apoB deficiency affecting intestinal and hepatic lipoproteins; genotype and lipid pattern distinguish it.
• Heterozygous APOB/PCSK9 hypobetalipoproteinemia: usually little or no infantile malabsorption.
• ANGPTL3 deficiency: combined hypolipidemia without characteristic fat-loaded enterocytes.
• Celiac disease, cystic fibrosis/pancreatic insufficiency, congenital diarrheal disorders, cholestasis, food-protein disease: can cause malabsorption but not the characteristic normal-triglyceride hypocholesterolemia plus absent postprandial apoB-48.

Population newborn screening is not established. Targeted biochemical/genetic testing, sibling cascade testing, and parental carrier testing are appropriate (ferreira2018chylomicronretentiondisease pages 6-7, peretti2018lessonsfromchylomicron pages 1-3).

11. Outcome and prognosis

No reliable five- or ten-year survival, mortality rate, or life-expectancy estimate exists. Available evidence suggests that treated patients can reach adulthood and that morbidity, rather than early mortality, is the principal concern. Early therapy commonly resolves diarrhea and improves weight, while hypocholesterolemia and vitamin E deficiency may persist (peretti2010guidelinesforthe pages 9-10, ferreira2018chylomicronretentiondisease pages 5-6).

Delayed diagnosis can permanently compromise growth: seven patients in the major clinical experience failed to reach the 20th percentile of predicted growth potential. Potential complications include neuropathy, ataxia, myopathy, retinal degeneration, osteopenia, delayed puberty, coagulopathy, anemia, hepatic steatosis, and cardiomyopathy. Moderate macrovesicular steatosis is reported, but the guideline review found no established progression to steatohepatitis or cirrhosis. Prognostic factors are age at treatment, adequacy/adherence of vitamin E and caloric replacement, dietary control of malabsorption, and baseline neurologic or retinal injury (peretti2018lessonsfromchylomicron pages 3-4, peretti2010guidelinesforthe pages 3-4, peretti2010guidelinesforthe pages 9-10).

12. Treatment and current applications

Standard management

There is no approved disease-modifying drug, gene therapy, RNA therapy, cell therapy, or surgery. Treatment is lifelong nutritional therapy:

• Restrict long-chain fat sufficiently to control diarrhea and steatorrhea without causing caloric deprivation.
• Supply essential fatty acids: approximately 3–5% of energy as omega-6 and 0.5–1% as omega-3; soybean oil and fish were specifically suggested.
• Consider medium-chain triglycerides as a chylomicron-independent energy source.
• Vitamin E: approximately 50 IU/kg/day orally, adjusted to biochemical and safety monitoring.
• Vitamin A: approximately 15,000 IU/day, adjusted to plasma level and toxicity risk.
• Vitamin D: approximately 800–1,200 IU/day or age-adjusted intermittent regimens. Some reproduced guideline tables contain an apparent “IU/kg/day” transcription; the original regimen should be verified before prescribing.
• Vitamin K: approximately 15 mg/week, adjusted to INR and vitamin status.
• Correct iron, calcium, and other deficiencies as indicated (peretti2010guidelinesforthe pages 10-11, peretti2010guidelinesforthe pages 9-10).

These are historical expert-guideline doses, not substitutes for specialist prescribing. Hypervitaminosis A/D and vitamin E–related bleeding are relevant safety considerations. Suggested NCIT intervention concepts include dietary therapy, low-fat diet, nutritional supplementation, vitamin E, vitamin A, vitamin D, vitamin K, medium-chain triglyceride, and genetic counseling.

Monitoring

Annual childhood assessment should include height/weight, gastrointestinal and neurologic status, diet, lipid profile, liver enzymes, CK, blood count, fat-soluble vitamins, INR, and essential fatty acids. After age ten, liver ultrasound, neurologic/muscular and ophthalmologic examination, electrophysiology where indicated, and bone-density assessment approximately every three years were proposed. Adult echocardiography every three years was also suggested (peretti2010guidelinesforthe pages 10-11, peretti2010guidelinesforthe pages 9-10).

Experimental and translational applications

No CRD-specific interventional trial was identified. A ClinicalTrials.gov search returned an observational carotenoid study in hypocholesterolemia (NCT05208879, completed; n=10), but its direct CRD enrollment and disease-specific utility were not established. Other retrieved “Anderson” trials concerned Anderson–Fabry disease and were irrelevant.

SAR1B biology is being considered as a lipid-lowering target because reducing enterocyte lipoprotein export could lower circulating cholesterol. Experts caution that broad SAR1B inhibition could reproduce malabsorption, vitamin deficiency, liver or muscle effects, and secretory-pathway toxicity. Intestine-restricted, partial, or cargo-selective modulation would therefore be required (peretti2018lessonsfromchylomicron pages 3-4, tang2023cargoselectionin pages 2-3).

13. Prevention

Primary prevention through lifestyle or vaccination is not applicable to the occurrence of a recessive genetic disorder. Reproductive prevention options include carrier testing of relatives, genetic counseling, partner testing, prenatal diagnosis, and preimplantation genetic testing when familial variants are known. Secondary prevention consists of cascade testing and rapid evaluation of symptomatic siblings; universal newborn screening is not currently established. Tertiary prevention is central: early dietary treatment and vitamin replacement, growth monitoring, and surveillance of liver, nervous system, retina, muscle, heart, coagulation, and bone reduce complications. No infectious prophylaxis, immunization specific to CRD, or environmental public-health intervention is indicated.

14. Other species and natural disease

No well-established naturally occurring veterinary counterpart or zoonotic form was identified. SAR1B is evolutionarily conserved across vertebrates, and orthologs exist in mouse and zebrafish. CRD is neither infectious nor transmissible between species. Breed-specific disease and VBO annotations were not found. Comparative importance lies in conserved COPII trafficking rather than animal-health prevalence (charcosset2008andersonorchylomicron pages 1-2, auclair2023highfatdietreveals pages 1-2).

15. Model organisms and experimental systems

Cellular models

CRISPR-disrupted human Caco-2/15 intestinal cells show reduced chylomicron secretion, impaired HDL biogenesis and cholesterol efflux, and oxidative stress. Combined SAR1A/SAR1B loss causes a more complete secretory block than SAR1B loss alone, revealing redundancy. Limitations include transformed-cell metabolism, absence of systemic dietary physiology, and incomplete modeling of development (sane2017understandingchylomicronretention pages 9-10, tang2023cargoselectionin pages 2-3).

Zebrafish

Sar1b-deficient zebrafish reproduce intestinal lipid-absorption and trafficking defects and are useful for developmental imaging and mechanistic screening. Their lipoprotein physiology and early development differ from humans, limiting direct therapeutic extrapolation.

Mouse

CRISPR mice bearing a targeted deletion or a patient-analogous Sar1b mutation reproduce intestinal lipid accumulation, steatorrhea, malabsorption, failed chylomicron secretion, hypocholesterolemia, and low HDL. Homozygous deletion/mutation is usually embryonic or neonatal lethal, unlike most human patients, so heterozygous mice have been used for metabolic experiments even though human heterozygotes are generally asymptomatic. This genotype mismatch is an important limitation (auclair2023highfatdietreveals pages 1-2, auclair2023highfatdietreveals pages 11-13, lu2020consequencesofmutations pages 2-4).

The 2023 high-fat-diet study demonstrated that diet, sex, and allele type alter the model phenotype. It found changes in hepatic and intestinal steatosis, insulin sensitivity, saturated/polyunsaturated fatty-acid balance, omega-6/omega-3 ratio, and ER-stress responses. These data strengthen the concept that SAR1B regulates broader cholesterol and metabolic homeostasis, but small subgroup and histology sample sizes constrain inference (auclair2023highfatdietreveals pages 11-13, auclair2023highfatdietreveals pages 9-10, auclair2023highfatdietreveals pages 4-5).

Evidence hierarchy, recent developments, and limitations

The most authoritative clinical management evidence remains the 2010 two-center guideline because no newer controlled treatment study exists. Its abstract directly states that treatment includes “fat-soluble vitamin supplements and large amounts of vitamin E” and emphasizes maintaining both calories and essential fatty acids (published 22 September 2010; DOI 10.1186/1750-1172-5-24) (peretti2010guidelinesforthe pages 1-3).

The major recent synthesis is Levy et al., July 2024, Biomedicines 12:1548, DOI 10.3390/biomedicines12071548. Its abstract concludes that SAR1B loss-of-function not only predisposes to CRD but may “exacerbate oxidative stress, inflammation, and ER stress”; these secondary mechanisms are primarily based on cellular and animal evidence rather than prospective human data (levy2024unravelingchylomicronretention pages 1-2).

The principal recent primary mechanistic study is Auclair et al., September 2023, Journal of Lipid Research 64:100423, DOI 10.1016/j.jlr.2023.100423, which established diet-, sex-, and allele-dependent metabolic effects in engineered mice (auclair2023highfatdietreveals pages 1-2, auclair2023highfatdietreveals pages 9-10).

Overall certainty is high for autosomal-recessive SAR1B causation, impaired COPII-dependent pre-chylomicron trafficking, the biochemical/endoscopic signature, and benefit of early nutritional therapy. Certainty is moderate or low for exact prevalence, phenotype penetrance, genotype–phenotype correlation, human sex effects, secondary inflammatory/ER-stress mechanisms, long-term survival, optimal vitamin doses, and advanced therapeutics because CRD remains exceptionally rare and lacks registries or controlled trials.

References

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8. (sane2017understandingchylomicronretention pages 9-10): Alain Théophile Sané, Ernest Seidman, Noel Peretti, Marie Laure Kleme, Edgard Delvin, Colette Deslandres, Carole Garofalo, Schohraya Spahis, and Emile Levy. Understanding chylomicron retention disease through sar1b gtpase gene disruption: insight from cell culture. Arteriosclerosis, Thrombosis, and Vascular Biology, 37:2243–2251, Dec 2017. URL: https://doi.org/10.1161/atvbaha.117.310121, doi:10.1161/atvbaha.117.310121. This article has 64 citations and is from a domain leading peer-reviewed journal.

9. (levy2024unravelingchylomicronretention pages 10-12): Emile Levy, Catherine Fallet-Bianco, Nickolas Auclair, Natalie Patey, Valérie Marcil, Alain Théophile Sané, and Schohraya Spahis. Unraveling chylomicron retention disease enhances insight into sar1b gtpase functions and mechanisms of actions, while shedding light of intracellular chylomicron trafficking. Jul 2024. URL: https://doi.org/10.3390/biomedicines12071548, doi:10.3390/biomedicines12071548. This article has 1 citations.

10. (levy2024unravelingchylomicronretention pages 1-2): Emile Levy, Catherine Fallet-Bianco, Nickolas Auclair, Natalie Patey, Valérie Marcil, Alain Théophile Sané, and Schohraya Spahis. Unraveling chylomicron retention disease enhances insight into sar1b gtpase functions and mechanisms of actions, while shedding light of intracellular chylomicron trafficking. Jul 2024. URL: https://doi.org/10.3390/biomedicines12071548, doi:10.3390/biomedicines12071548. This article has 1 citations.

11. (charcosset2008andersonorchylomicron pages 1-2): Mathilde Charcosset, Agnès Sassolas, Noël Peretti, Claude C. Roy, Colette Deslandres, Daniel Sinnett, Emile Levy, and Alain Lachaux. Anderson or chylomicron retention disease: molecular impact of five mutations in the sar1b gene on the structure and the functionality of sar1b protein. Molecular genetics and metabolism, 93 1:74-84, Jan 2008. URL: https://doi.org/10.1016/j.ymgme.2007.08.120, doi:10.1016/j.ymgme.2007.08.120. This article has 95 citations and is from a peer-reviewed journal.

12. (charcosset2008andersonorchylomicron pages 8-9): Mathilde Charcosset, Agnès Sassolas, Noël Peretti, Claude C. Roy, Colette Deslandres, Daniel Sinnett, Emile Levy, and Alain Lachaux. Anderson or chylomicron retention disease: molecular impact of five mutations in the sar1b gene on the structure and the functionality of sar1b protein. Molecular genetics and metabolism, 93 1:74-84, Jan 2008. URL: https://doi.org/10.1016/j.ymgme.2007.08.120, doi:10.1016/j.ymgme.2007.08.120. This article has 95 citations and is from a peer-reviewed journal.

13. (georges2011molecularanalysisand pages 8-11): Amandine Georges, Jessica Bonneau, Dominique Bonnefont-Rousselot, Jacqueline Champigneulle, Jean P Rabès, Marianne Abifadel, Thomas Aparicio, Jean C Guenedet, Eric Bruckert, Catherine Boileau, Alain Morali, Mathilde Varret, Lawrence P Aggerbeck, and Marie E Samson-Bouma. Molecular analysis and intestinal expression of sar1 genes and proteins in anderson's disease (chylomicron retention disease). Orphanet Journal of Rare Diseases, 6:1-1, Jan 2011. URL: https://doi.org/10.1186/1750-1172-6-1, doi:10.1186/1750-1172-6-1. This article has 89 citations and is from a peer-reviewed journal.

14. (peretti2010guidelinesforthe pages 10-11): Noel Peretti, Agnès Sassolas, Claude C Roy, Colette Deslandres, Mathilde Charcosset, Justine Castagnetti, Laurence Pugnet-Chardon, Philippe Moulin, Sylvie Labarge, Lise Bouthillier, Alain Lachaux, and Emile Levy. Guidelines for the diagnosis and management of chylomicron retention disease based on a review of the literature and the experience of two centers. Orphanet Journal of Rare Diseases, 5:24-24, Sep 2010. URL: https://doi.org/10.1186/1750-1172-5-24, doi:10.1186/1750-1172-5-24. This article has 155 citations and is from a peer-reviewed journal.

15. (peretti2010guidelinesforthe pages 9-10): Noel Peretti, Agnès Sassolas, Claude C Roy, Colette Deslandres, Mathilde Charcosset, Justine Castagnetti, Laurence Pugnet-Chardon, Philippe Moulin, Sylvie Labarge, Lise Bouthillier, Alain Lachaux, and Emile Levy. Guidelines for the diagnosis and management of chylomicron retention disease based on a review of the literature and the experience of two centers. Orphanet Journal of Rare Diseases, 5:24-24, Sep 2010. URL: https://doi.org/10.1186/1750-1172-5-24, doi:10.1186/1750-1172-5-24. This article has 155 citations and is from a peer-reviewed journal.

16. (auclair2023highfatdietreveals pages 1-2): Nickolas Auclair, Alain T. Sané, Léna Ahmarani, Nour-El-Houda Ould-Chikh, Nathalie Patey, Jean-François Beaulieu, Edgard Delvin, Schohraya Spahis, and Emile Levy. High-fat diet reveals the impact of sar1b defects on lipid and lipoprotein profile and cholesterol metabolism. Sep 2023. URL: https://doi.org/10.1016/j.jlr.2023.100423, doi:10.1016/j.jlr.2023.100423. This article has 10 citations and is from a peer-reviewed journal.

17. (auclair2023highfatdietreveals pages 11-13): Nickolas Auclair, Alain T. Sané, Léna Ahmarani, Nour-El-Houda Ould-Chikh, Nathalie Patey, Jean-François Beaulieu, Edgard Delvin, Schohraya Spahis, and Emile Levy. High-fat diet reveals the impact of sar1b defects on lipid and lipoprotein profile and cholesterol metabolism. Sep 2023. URL: https://doi.org/10.1016/j.jlr.2023.100423, doi:10.1016/j.jlr.2023.100423. This article has 10 citations and is from a peer-reviewed journal.

18. (auclair2023highfatdietreveals pages 9-10): Nickolas Auclair, Alain T. Sané, Léna Ahmarani, Nour-El-Houda Ould-Chikh, Nathalie Patey, Jean-François Beaulieu, Edgard Delvin, Schohraya Spahis, and Emile Levy. High-fat diet reveals the impact of sar1b defects on lipid and lipoprotein profile and cholesterol metabolism. Sep 2023. URL: https://doi.org/10.1016/j.jlr.2023.100423, doi:10.1016/j.jlr.2023.100423. This article has 10 citations and is from a peer-reviewed journal.

19. (peretti2018lessonsfromchylomicron pages 3-4): Noel Peretti. Lessons from chylomicron retention disease: a potential new approach for the treatment of hypercholesterolemia? Expert Opinion on Orphan Drugs, 6:163-165, Feb 2018. URL: https://doi.org/10.1080/21678707.2018.1438259, doi:10.1080/21678707.2018.1438259. This article has 4 citations.

20. (peretti2010guidelinesforthe pages 1-3): Noel Peretti, Agnès Sassolas, Claude C Roy, Colette Deslandres, Mathilde Charcosset, Justine Castagnetti, Laurence Pugnet-Chardon, Philippe Moulin, Sylvie Labarge, Lise Bouthillier, Alain Lachaux, and Emile Levy. Guidelines for the diagnosis and management of chylomicron retention disease based on a review of the literature and the experience of two centers. Orphanet Journal of Rare Diseases, 5:24-24, Sep 2010. URL: https://doi.org/10.1186/1750-1172-5-24, doi:10.1186/1750-1172-5-24. This article has 155 citations and is from a peer-reviewed journal.

21. (georges2011molecularanalysisand pages 11-12): Amandine Georges, Jessica Bonneau, Dominique Bonnefont-Rousselot, Jacqueline Champigneulle, Jean P Rabès, Marianne Abifadel, Thomas Aparicio, Jean C Guenedet, Eric Bruckert, Catherine Boileau, Alain Morali, Mathilde Varret, Lawrence P Aggerbeck, and Marie E Samson-Bouma. Molecular analysis and intestinal expression of sar1 genes and proteins in anderson's disease (chylomicron retention disease). Orphanet Journal of Rare Diseases, 6:1-1, Jan 2011. URL: https://doi.org/10.1186/1750-1172-6-1, doi:10.1186/1750-1172-6-1. This article has 89 citations and is from a peer-reviewed journal.

22. (ferreira2018chylomicronretentiondisease pages 5-6): Helena Ferreira, Raquel Nuñez Ramos, Cinthia Flores Quan, Susana Redecillas Ferreiro, Vanessa Cabello Ruiz, Javi Juampérez Goñi, Jesus Quintero Bernabeu, Oscar Segarra Cantón, and Marina Álvarez Beltran. Chylomicron retention disease: a description of a new mutation in a very rare disease. Pediatric Gastroenterology, Hepatology & Nutrition, 21:134-140, Apr 2018. URL: https://doi.org/10.5223/pghn.2018.21.2.134, doi:10.5223/pghn.2018.21.2.134. This article has 14 citations and is from a peer-reviewed journal.

23. (lu2020consequencesofmutations pages 2-4): Chung-Ling Lu and Jinoh Kim. Consequences of mutations in the genes of the er export machinery copii in vertebrates. Mar 2020. URL: https://doi.org/10.1007/s12192-019-01062-3, doi:10.1007/s12192-019-01062-3. This article has 25 citations and is from a peer-reviewed journal.

24. (auclair2023highfatdietreveals pages 4-5): Nickolas Auclair, Alain T. Sané, Léna Ahmarani, Nour-El-Houda Ould-Chikh, Nathalie Patey, Jean-François Beaulieu, Edgard Delvin, Schohraya Spahis, and Emile Levy. High-fat diet reveals the impact of sar1b defects on lipid and lipoprotein profile and cholesterol metabolism. Sep 2023. URL: https://doi.org/10.1016/j.jlr.2023.100423, doi:10.1016/j.jlr.2023.100423. This article has 10 citations and is from a peer-reviewed journal.

Artifacts

• Edison artifact artifact-00

Reference Validation

Checked with linkml-reference-validator 0.2.1.

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

• MONDO:0009528 (4 mentions) - the report calls it "if available"; MONDO calls it chylomicron retention disease