Cerebellar Ataxia-Hypogonadism Syndrome

Mendelian MONDO:0008935 Pathograph 19 Show in embeddings browser

Cerebellar ataxia-hypogonadism syndrome (Gordon Holmes syndrome) is a rare, genetically heterogeneous autosomal recessive neurodegenerative-neuroendocrine disorder defined by the combination of progressive cerebellar ataxia and hypogonadotropic hypogonadism, frequently accompanied by cognitive decline/dementia, additional movement disorders (chorea, parkinsonism, dystonia), and cerebral white-matter changes. Most cases are caused by biallelic loss-of-function variants in the ubiquitin/proteostasis genes RNF216 (an RBR-class E3 ubiquitin ligase) and STUB1 (CHIP), with a digenic RNF216/OTUD4 form, while biallelic PNPLA6 (neuropathy target esterase) variants produce an allelic continuum that overlaps with Boucher-Neuhauser syndrome (ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy). The disorder belongs to a clinical continuum of neurodegenerative ataxias with reproductive endocrine failure first described by Gordon Holmes in 1908.

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4
Pathophys.
23
Phenotypes
19
Pathograph
4
Genes
4
Medical Actions
1
References
1
Deep Research
⚙

Pathophysiology

4
Disordered Ubiquitination and Impaired Protein Quality Control
The core molecular lesion in RNF216-, OTUD4-, and STUB1/CHIP-related Gordon Holmes syndrome is disruption of the ubiquitin-proteasome system and protein quality control. RNF216 is an RBR/RING-class E3 ubiquitin ligase that attaches ubiquitin to substrates (including upstream activators of NF-kB signaling), marking them for proteasome-mediated degradation; OTUD4 is a partnering deubiquitinase. STUB1 encodes CHIP, a co-chaperone E3 ligase central to protein quality control. Biallelic loss-of-function (or loss of critical E3 activity) in these enzymes impairs ubiquitination and turnover of client proteins. The digenic RNF216/OTUD4 form reflects an epistatic interaction within a shared pathway.
RNF216 hgnc:21698 OTUD4 hgnc:24949 STUB1 hgnc:11427
protein ubiquitination GO:0016567 ↓ DECREASED ubiquitin-dependent protein catabolic process GO:0006511 ↓ DECREASED
ubiquitin protein ligase activity GO:0061630 ↓ DECREASED
Downstream
Cerebellar and Hippocampal Neurodegeneration Impaired ubiquitination leads to accumulation of toxic proteins (ubiquitin-immunoreactive intranuclear inclusions) and progressive neuronal loss in cerebellar pathways and hippocampus.
Reproductive Endocrine Axis Dysfunction The same ubiquitination defect impairs the hypothalamic-pituitary-gonadal axis, producing central hypogonadotropic hypogonadism.
Show evidence (3 references)
PMID:23656588 SUPPORT Human Clinical
"Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family."
The landmark NEJM study identifies biallelic RNF216 and digenic RNF216/OTUD4 mutations in ubiquitin pathway enzymes as the cause.
PMID:23656588 SUPPORT Human Clinical
"These findings link disordered ubiquitination to neurodegeneration and reproductive dysfunction"
Establishes disordered ubiquitination as the unifying mechanism linking neurodegeneration to reproductive endocrine failure.
PMID:24113144 SUPPORT In Vitro
"Introduction of the Thr246Met mutation into CHIP results in a loss of ubiquitin ligase activity measured directly using recombinant proteins as well as in cell culture models."
Functional assays demonstrate that the STUB1/CHIP disease variant abolishes E3 ubiquitin ligase activity, implicating impaired protein quality control.
Cerebellar and Hippocampal Neurodegeneration
Progressive loss of Purkinje cells and cerebellar pathway neurons underlies the ataxia, while hippocampal and cortical neuronal loss contributes to cognitive decline and dementia. Cerebellar atrophy and subcortical cerebral white-matter hyperintensities are characteristic imaging correlates. In an Rnf216 knockout mouse model, age- and sex-dependent microglial alterations in hippocampus and cortex accompany learning impairments, suggesting microglial activation/neuroinflammation as a candidate intermediate.
Purkinje cell CL:0000121 microglial cell CL:0000129
inflammatory response GO:0006954 ↑ INCREASED
cerebellum UBERON:0002037
Downstream
Abnormality of speech or vocalization Cerebellar neurodegeneration disrupts motor speech and vocalization.
Hemiplegia/hemiparesis Neurodegenerative involvement can include asymmetric corticospinal motor impairment.
Personality changes Hippocampal and broader forebrain involvement contributes to behavioral and personality change.
Show evidence (2 references)
PMID:23656588 SUPPORT Human Clinical
"Neuronal loss was observed in cerebellar pathways and the hippocampus"
Documents the neurodegenerative substrate (cerebellar and hippocampal neuronal loss) for ataxia and dementia.
PMID:38164552 SUPPORT Model Organism
"KO mice also showed age-dependent strategy and associative learning impairments with sex-dependent alterations of microglia in the hippocampus and cortex."
The Rnf216 knockout mouse implicates microglial alterations and neuroinflammation in cognitive impairment, a candidate mechanistic intermediate.
Reproductive Endocrine Axis Dysfunction
Central (hypogonadotropic) hypogonadism arises from dysfunction at the hypothalamic GnRH-neuron and pituitary gonadotrope levels. Pulsatile GnRH administration can transiently restore gonadotropin and sex-steroid secretion early in the course, indicating a primarily hypothalamic GnRH deficiency with a superimposed and progressive pituitary component. The result is delayed/absent puberty, lack of secondary sexual characteristics, and low gonadotropins and sex steroids.
hypothalamic gonadotropin-releasing hormone neuron CL:0011111
pituitary gland UBERON:0000007
Downstream
Hypogonadism Hypothalamic-pituitary-gonadal axis failure manifests clinically as hypogonadism.
Abnormality of the hypothalamus-pituitary axis The endocrine lesion localizes to hypothalamic and pituitary levels.
Decreased fertility Central hypogonadism reduces reproductive capacity.
Gynecomastia Disrupted gonadal steroid signaling can manifest as gynecomastia.
Show evidence (2 references)
PMID:23656588 SUPPORT Human Clinical
"Defects were detected at the hypothalamic and pituitary levels of the reproductive endocrine axis."
Localizes the hypogonadotropic hypogonadism to combined hypothalamic and pituitary dysfunction.
PMID:24113144 SUPPORT Model Organism
"Loss of CHIP function in mice resulted in behavioral and reproductive impairments that mimic human ataxia and hypogonadism."
A CHIP-deficient mouse recapitulates the combined ataxia and reproductive (hypogonadism) phenotype.
PNPLA6 / Neuropathy Target Esterase Phospholipid Dysfunction
A genetically distinct arm of the ataxia-hypogonadism continuum is caused by biallelic PNPLA6 variants. PNPLA6 encodes neuropathy target esterase (NTE), an endoplasmic-reticulum-localized lysophospholipase regulating membrane phospholipid homeostasis. PNPLA6 disorders span Boucher-Neuhauser syndrome (ataxia, hypogonadotropic hypogonadism, chorioretinal dystrophy), Gordon Holmes syndrome, spastic paraplegia type 39, Oliver-McFarlane, and Laurence-Moon syndromes, with age-dependent, multisystem manifestations affecting cerebellum, retina, peripheral nerves, and endocrine axes.
PNPLA6 hgnc:16268
endoplasmic reticulum GO:0005783
Downstream
Cerebellar and Hippocampal Neurodegeneration PNPLA6 phospholipid dysfunction in cerebellar neurons causes progressive cerebellar atrophy and ataxia, with cerebellar atrophy documented by MRI in the majority of patients.
Reproductive Endocrine Axis Dysfunction PNPLA6 dysfunction also impairs the reproductive endocrine axis, producing hypogonadotropic hypogonadism in a substantial proportion of patients.
Abnormal electroretinogram PNPLA6-related retinal dysfunction can be detected electrophysiologically.
Nystagmus Retinal and cerebellar involvement can manifest with abnormal ocular movements.
Optic atrophy PNPLA6-associated neuro-ophthalmologic degeneration can include optic atrophy.
Abnormality of retinal pigmentation PNPLA6-related chorioretinal disease manifests with abnormal retinal pigmentation.
Show evidence (2 references)
PMID:35069422 SUPPORT Human Clinical
"A wide spectrum of neurodegenerative diseases has been associated with pathogenic variants in the PNPLA6 (patatin-like phospholipase domain-containing protein 6) gene, including spastic paraplegia type 39, Gordon-Holmes, Boucher-Neuhauser, Oliver-Mc Farlane, and Laurence-Moon syndromes."
Establishes PNPLA6 as a cause of the Gordon Holmes / Boucher-Neuhauser ataxia-hypogonadism continuum.
PMID:25299038 SUPPORT Human Clinical
"PNPLA6 disorders span a phenotypic continuum characterized by variable combinations of cerebellar ataxia; upper motor neuron involvement manifesting as spasticity and/or brisk reflexes; chorioretinal dystrophy associated with variable degrees of reduced visual function; and hypogonadotropic hypogonadism"
GeneReviews defines the PNPLA6 phenotypic continuum encompassing the ataxia-hypogonadism syndromes.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Cerebellar Ataxia-Hypogonadism Syndrome Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

23
Breast 1
Gynecomastia VERY_FREQUENT Gynecomastia HP:0000771
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000771 | Gynecomastia | Very frequent (99-80%)"
Orphanet lists gynecomastia as a very frequent phenotype.
Endocrine 3
Hypogonadotropic hypogonadism Hypogonadotropic hypogonadism HP:0000044
Show evidence (2 references)
PMID:39444518 SUPPORT Human Clinical
"Biallelic pathogenic variants in RNF216 cause a syndrome characterized by hypogonadotropic hypogonadism, cerebellar ataxia, chorea, and cognitive impairment, a combination first described as Gordon Holmes syndrome (MIM 212840)."
Defines hypogonadotropic hypogonadism as a core feature of the RNF216 syndrome.
PMID:39444518 SUPPORT Human Clinical
"hypogonadotropic hypogonadism may be the initial manifestation of this severe neuroendocrine disorder, especially in males."
Hypogonadism can precede neurologic signs as the presenting complaint.
Hypogonadism VERY_FREQUENT Hypogonadism HP:0000135
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000135 | Hypogonadism | Very frequent (99-80%)"
Orphanet lists hypogonadism as a very frequent phenotype.
Delayed puberty Delayed puberty HP:0000823
Show evidence (1 reference)
PMID:39444518 SUPPORT Human Clinical
"We report 2 siblings who were referred due to absent or delayed puberty."
Affected siblings presented with absent or delayed puberty.
Eye 5
Chorioretinal dystrophy Chorioretinal dystrophy HP:0001135
Show evidence (2 references)
PMID:33650466 SUPPORT Human Clinical
"neurologic, ophthalmologic, endocrine, and genetic evaluations established a diagnosis of BNHS"
Chorioretinal dystrophy is a defining feature of the Boucher-Neuhauser (PNPLA6) form.
PMID:25299038 SUPPORT Human Clinical
"chorioretinal dystrophy associated with variable degrees of reduced visual function"
GeneReviews documents chorioretinal dystrophy with reduced visual function in PNPLA6 disorders.
Abnormal electroretinogram VERY_FREQUENT Abnormal electroretinogram HP:0000512
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000512 | Abnormal electroretinogram | Very frequent (99-80%)"
Orphanet lists abnormal electroretinogram as a very frequent phenotype.
Nystagmus VERY_FREQUENT Nystagmus HP:0000639
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000639 | Nystagmus | Very frequent (99-80%)"
Orphanet lists nystagmus as a very frequent phenotype.
Optic atrophy VERY_FREQUENT Optic atrophy HP:0000648
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000648 | Optic atrophy | Very frequent (99-80%)"
Orphanet lists optic atrophy as a very frequent phenotype.
Abnormality of retinal pigmentation VERY_FREQUENT Abnormal retinal pigmentation HP:0007703
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0007703 | Abnormality of retinal pigmentation | Very frequent (99-80%)"
Orphanet lists abnormality of retinal pigmentation as a very frequent phenotype.
Genitourinary 1
Primary amenorrhea Primary amenorrhea HP:0000786
Show evidence (1 reference)
PMID:39444518 SUPPORT Human Clinical
"His 15-year-old sister was referred due to primary amenorrhea."
An affected female sibling presented with primary amenorrhea.
Nervous System 9
Cerebellar ataxia Ataxia HP:0001251
Course: PROGRESSIVE
Show evidence (2 references)
PMID:24113144 SUPPORT Human Clinical
"Gordon Holmes syndrome (GHS) is a rare Mendelian neurodegenerative disorder characterized by ataxia and hypogonadism."
Ataxia is one of the two defining clinical features of the syndrome.
PMID:23656588 SUPPORT Human Clinical
"All patients had progressive ataxia and dementia."
All RNF216-mutation patients in the index cohort had progressive ataxia.
Cognitive decline and dementia Dementia HP:0000726
Course: PROGRESSIVE
Show evidence (2 references)
PMID:23656588 SUPPORT Human Clinical
"Dementia was also prominent, with personality changes and memory loss occurring at the onset of the disease"
Dementia with personality changes and memory loss is prominent in RNF216-related disease.
PMID:37161390 SUPPORT Human Clinical
"Gordon Holmes syndrome (GHS) is a rare autosomal recessive disorder characterized by hypogonadotropic hypogonadism, cognitive decline, and cerebellar ataxia."
Cognitive decline is listed as one of the core GHS features.
Personality changes OCCASIONAL Personality changes HP:0000751
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000751 | Personality changes | Occasional (29-5%)"
Orphanet lists personality changes as an occasional phenotype.
Cerebellar atrophy Cerebellar atrophy HP:0001272
Show evidence (2 references)
PMID:35069422 SUPPORT Human Clinical
"Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII)."
Cerebellar atrophy with vermian predominance was found in most PNPLA6 patients.
PMID:37977846 SUPPORT Human Clinical
"pan-cerebellar atrophy with bilateral cerebral white matter hyperintensities"
Pan-cerebellar atrophy documented in an RNF216 case.
Cerebral white matter abnormality Abnormal cerebral white matter morphology HP:0002500
Show evidence (2 references)
PMID:23656588 SUPPORT Human Clinical
"The subcortical white matter contained patchy areas of hyperintensity on T2-weighted imaging and fluid-attenuated inversion recovery (FLAIR) imaging"
Subcortical white-matter hyperintensities are documented across RNF216-mutation patients.
PMID:39444518 SUPPORT Human Clinical
"an extensive supratentorial leuko-encephalopathy"
Extensive supratentorial leukoencephalopathy was found on MRI in an RNF216 case.
Chorea Chorea HP:0002072
Show evidence (1 reference)
PMID:39444518 SUPPORT Human Clinical
"Biallelic pathogenic variants in RNF216 cause a syndrome characterized by hypogonadotropic hypogonadism, cerebellar ataxia, chorea, and cognitive impairment"
Chorea is part of the RNF216 syndrome phenotype.
Dysarthria Dysarthria HP:0001260
Show evidence (1 reference)
PMID:23656588 SUPPORT Human Clinical
"Dysarthria was the initial neurologic symptom in some patients"
Dysarthria can be the presenting neurologic feature.
Abnormality of speech or vocalization VERY_FREQUENT Abnormal speech pattern HP:0002167
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0002167 | Abnormality of speech or vocalization | Very frequent (99-80%)"
Orphanet lists abnormality of speech or vocalization as a very frequent phenotype.
Hyperreflexia Hyperreflexia HP:0001347
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"Gordon Holmes syndrome (cerebellar ataxia, hypogonadotropic hypogonadism, and – to a variable degree – brisk reflexes)"
GeneReviews lists variable brisk reflexes within the Gordon Holmes cluster of PNPLA6 disorders.
Other 4
Abnormality of the hypothalamus-pituitary axis VERY_FREQUENT Abnormality of the hypothalamus-pituitary axis HP:0000864
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000864 | Abnormality of the hypothalamus-pituitary axis | Very frequent (99-80%)"
Orphanet lists hypothalamus-pituitary axis abnormality as a very frequent phenotype.
Decreased fertility VERY_FREQUENT Decreased fertility HP:0000144
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0000144 | Decreased fertility | Very frequent (99-80%)"
Orphanet lists decreased fertility as a very frequent phenotype.
Peripheral axonal neuropathy Peripheral axonal neuropathy HP:0003477
Show evidence (1 reference)
PMID:35069422 SUPPORT Human Clinical
"peripheral axonal neuropathy (4/8)"
Peripheral axonal neuropathy occurred in half of the PNPLA6 cohort.
Hemiplegia/hemiparesis FREQUENT Hemiplegia/hemiparesis HP:0004374
Show evidence (1 reference)
ORPHA:1173 SUPPORT Other
"HP:0004374 | Hemiplegia/hemiparesis | Frequent (79-30%)"
Orphanet lists hemiplegia/hemiparesis as a frequent phenotype.
🧬

Genetic Associations

4
RNF216 biallelic pathogenic variants (Causative biallelic (and digenic with OTUD4) pathogenic variants)
Gene: RNF216 hgnc:21698 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (2 references)
PMID:23656588 SUPPORT Human Clinical
"The syndrome of hypogonadotropic hypogonadism, ataxia, and dementia can be caused by inactivating mutations in RNF216 or by the combination of mutations in RNF216 and OTUD4."
Establishes RNF216 (and digenic RNF216/OTUD4) as the genetic cause.
PMID:27441066 SUPPORT Human Clinical
"We identified a novel splicing variant in RNF216 that is likely to abolish the canonical splice site at the junction of exon/intron 13 (NM_207111.3:c.2061G>A)."
A novel RNF216 splice-site variant causes GHS, illustrating allelic heterogeneity.
OTUD4 (digenic with RNF216) pathogenic variants (Digenic contributor with RNF216)
Gene: OTUD4 hgnc:24949 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:23656588 SUPPORT Human Clinical
"Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family."
Documents OTUD4 as a digenic contributor with RNF216.
STUB1 (CHIP) biallelic pathogenic variants (Causative biallelic pathogenic variants)
Gene: STUB1 hgnc:11427 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:24113144 SUPPORT Human Clinical
"identified a homozygous mutation in STUB1 (NM_005861) c.737C→T, p.Thr246Met, a gene that encodes the protein CHIP (C-terminus of HSC70-interacting protein)."
Identifies a homozygous STUB1/CHIP variant causing GHS.
PNPLA6 biallelic pathogenic variants (Causative biallelic pathogenic variants (Gordon Holmes / Boucher-Neuhauser continuum))
Gene: PNPLA6 hgnc:16268 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (2 references)
PMID:35069422 SUPPORT Human Clinical
"We identified six novel and four recurrent PNPLA6 gene variants in eight patients (2.7%)."
Quantifies PNPLA6 variant detection in an ataxia/spastic paraplegia screening cohort.
PMID:33650466 SUPPORT Human Clinical
"We identified a missense homozygous variant (c.3524 C > G (p.Ser1175Cys)) in the PNPLA6 gene, which explains the phenotype of the patient"
A homozygous PNPLA6 missense variant causes Boucher-Neuhauser within the continuum.
💊

Medical Actions

4
Sex Hormone Replacement Therapy
Action: Hormone Replacement Therapy NCIT:C15599
Agent: testosterone CHEBI:17347 estradiol CHEBI:23965
Hormone replacement therapy for hypogonadotropic hypogonadism (testosterone in males, estrogen/progesterone in females) is given at the expected time of puberty to induce and maintain secondary sexual characteristics and menstruation and to support fertility planning. In RNF216 case series, testosterone therapy improved secondary sexual characteristics but did not alter neurologic signs.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"Hypogonadotropic hypogonadism. Hormone replacement therapy at the expected time of puberty."
GeneReviews recommends hormone replacement therapy for the hypogonadotropic hypogonadism.
Multidisciplinary Supportive and Rehabilitative Care
Action: supportive care MAXO:0000950
Management is symptomatic and individually tailored: continuous training of speech and swallowing, fine-motor skills, gait, and balance for ataxia; physical therapy and assistive devices for spasticity; low-vision aids for chorioretinal dystrophy; and periodic multidisciplinary reevaluation. No disease-modifying therapy exists.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"Management is symptomatic and individually tailored."
GeneReviews describes symptomatic, individually tailored supportive management.
Physical Therapy
Action: Physical Therapy NCIT:C15302
Physical therapy, assistive walking devices, and ankle-foot orthotics to improve strength and agility and prevent contractures, particularly when spasticity is present.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"Interventions to improve strength and agility and to prevent contractures, such as physical therapy, assistive walking devices and/or ankle-foot orthotics"
GeneReviews recommends physical therapy and assistive devices for spasticity.
Genetic Counseling
Action: Genetic Counseling NCIT:C15240
Genetic counseling for affected families. Once the pathogenic variants are identified, carrier testing, prenatal testing, and preimplantation genetic testing are possible.
Show evidence (1 reference)
PMID:25299038 SUPPORT Human Clinical
"carrier testing for at-risk relatives, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing are possible."
GeneReviews outlines genetic counseling and reproductive testing options.
{ }

Source YAML

click to show 
name: Cerebellar Ataxia-Hypogonadism Syndrome
creation_date: "2026-06-04T12:00:00Z"
category: Mendelian
description: >-
  Cerebellar ataxia-hypogonadism syndrome (Gordon Holmes syndrome) is a rare,
  genetically heterogeneous autosomal recessive neurodegenerative-neuroendocrine
  disorder defined by the combination of progressive cerebellar ataxia and
  hypogonadotropic hypogonadism, frequently accompanied by cognitive
  decline/dementia, additional movement disorders (chorea, parkinsonism,
  dystonia), and cerebral white-matter changes. Most cases are caused by
  biallelic loss-of-function variants in the ubiquitin/proteostasis genes
  RNF216 (an RBR-class E3 ubiquitin ligase) and STUB1 (CHIP), with a digenic
  RNF216/OTUD4 form, while biallelic PNPLA6 (neuropathy target esterase)
  variants produce an allelic continuum that overlaps with Boucher-Neuhauser
  syndrome (ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy).
  The disorder belongs to a clinical continuum of neurodegenerative ataxias with
  reproductive endocrine failure first described by Gordon Holmes in 1908.
disease_term:
  preferred_term: Cerebellar Ataxia-Hypogonadism Syndrome
  term:
    id: MONDO:0008935
    label: cerebellar ataxia-hypogonadism syndrome
synonyms:
- Gordon Holmes syndrome
- Gordon-Holmes syndrome
- ataxia-hypogonadotropic hypogonadism
- ataxia, dementia, and hypogonadotropism

references:
- reference: PMID:25299038
  title: "PNPLA6 Disorders."
  tags:
  - GeneReviews

pathophysiology:
- name: Disordered Ubiquitination and Impaired Protein Quality Control
  description: >
    The core molecular lesion in RNF216-, OTUD4-, and STUB1/CHIP-related Gordon
    Holmes syndrome is disruption of the ubiquitin-proteasome system and protein
    quality control. RNF216 is an RBR/RING-class E3 ubiquitin ligase that
    attaches ubiquitin to substrates (including upstream activators of NF-kB
    signaling), marking them for proteasome-mediated degradation; OTUD4 is a
    partnering deubiquitinase. STUB1 encodes CHIP, a co-chaperone E3 ligase
    central to protein quality control. Biallelic loss-of-function (or
    loss of critical E3 activity) in these enzymes impairs ubiquitination and
    turnover of client proteins. The digenic RNF216/OTUD4 form reflects an
    epistatic interaction within a shared pathway.
  genes:
  - preferred_term: RNF216
    term:
      id: hgnc:21698
      label: RNF216
  - preferred_term: OTUD4
    term:
      id: hgnc:24949
      label: OTUD4
  - preferred_term: STUB1
    term:
      id: hgnc:11427
      label: STUB1
  molecular_functions:
  - preferred_term: ubiquitin protein ligase activity
    term:
      id: GO:0061630
      label: ubiquitin protein ligase activity
    modifier: DECREASED
  biological_processes:
  - preferred_term: protein ubiquitination
    term:
      id: GO:0016567
      label: protein ubiquitination
    modifier: DECREASED
  - preferred_term: ubiquitin-dependent protein catabolic process
    term:
      id: GO:0006511
      label: ubiquitin-dependent protein catabolic process
    modifier: DECREASED
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family."
    explanation: >
      The landmark NEJM study identifies biallelic RNF216 and digenic
      RNF216/OTUD4 mutations in ubiquitin pathway enzymes as the cause.
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "These findings link disordered ubiquitination to neurodegeneration and reproductive dysfunction"
    explanation: >
      Establishes disordered ubiquitination as the unifying mechanism linking
      neurodegeneration to reproductive endocrine failure.
  - reference: PMID:24113144
    reference_title: "Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the U box protein CHIP."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Introduction of the Thr246Met mutation into CHIP results in a loss of ubiquitin ligase activity measured directly using recombinant proteins as well as in cell culture models."
    explanation: >
      Functional assays demonstrate that the STUB1/CHIP disease variant abolishes
      E3 ubiquitin ligase activity, implicating impaired protein quality control.
  downstream:
  - target: Cerebellar and Hippocampal Neurodegeneration
    description: >
      Impaired ubiquitination leads to accumulation of toxic proteins
      (ubiquitin-immunoreactive intranuclear inclusions) and progressive neuronal
      loss in cerebellar pathways and hippocampus.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23656588
      reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Neuronal loss was observed in cerebellar pathways and the hippocampus; surviving hippocampal neurons contained ubiquitin-immunoreactive intranuclear inclusions."
      explanation: >
        Neuropathology directly links the ubiquitination defect to cerebellar and
        hippocampal neurodegeneration with protein inclusions.
  - target: Reproductive Endocrine Axis Dysfunction
    description: >
      The same ubiquitination defect impairs the hypothalamic-pituitary-gonadal
      axis, producing central hypogonadotropic hypogonadism.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23656588
      reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Defects were detected at the hypothalamic and pituitary levels of the reproductive endocrine axis."
      explanation: >
        Endocrine phenotyping localizes the reproductive defect to hypothalamic
        and pituitary levels of the HPG axis.

- name: Cerebellar and Hippocampal Neurodegeneration
  description: >
    Progressive loss of Purkinje cells and cerebellar pathway neurons underlies
    the ataxia, while hippocampal and cortical neuronal loss contributes to
    cognitive decline and dementia. Cerebellar atrophy and subcortical cerebral
    white-matter hyperintensities are characteristic imaging correlates. In an
    Rnf216 knockout mouse model, age- and sex-dependent microglial alterations
    in hippocampus and cortex accompany learning impairments, suggesting
    microglial activation/neuroinflammation as a candidate intermediate.
  cell_types:
  - preferred_term: Purkinje cell
    term:
      id: CL:0000121
      label: Purkinje cell
  - preferred_term: microglial cell
    term:
      id: CL:0000129
      label: microglial cell
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  locations:
  - preferred_term: cerebellum
    term:
      id: UBERON:0002037
      label: cerebellum
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Neuronal loss was observed in cerebellar pathways and the hippocampus"
    explanation: >
      Documents the neurodegenerative substrate (cerebellar and hippocampal
      neuronal loss) for ataxia and dementia.
  - reference: PMID:38164552
    reference_title: "Gordon Holmes Syndrome Model Mice Exhibit Alterations in Microglia, Age, and Sex-Specific Disruptions in Cognitive and Proprioceptive Function."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "KO mice also showed age-dependent strategy and associative learning impairments with sex-dependent alterations of microglia in the hippocampus and cortex."
    explanation: >
      The Rnf216 knockout mouse implicates microglial alterations and
      neuroinflammation in cognitive impairment, a candidate mechanistic
      intermediate.
  downstream:
  - target: Abnormality of speech or vocalization
    description: >
      Cerebellar neurodegeneration disrupts motor speech and vocalization.
  - target: Hemiplegia/hemiparesis
    description: >
      Neurodegenerative involvement can include asymmetric corticospinal motor
      impairment.
  - target: Personality changes
    description: >
      Hippocampal and broader forebrain involvement contributes to behavioral
      and personality change.

- name: Reproductive Endocrine Axis Dysfunction
  description: >
    Central (hypogonadotropic) hypogonadism arises from dysfunction at the
    hypothalamic GnRH-neuron and pituitary gonadotrope levels. Pulsatile GnRH
    administration can transiently restore gonadotropin and sex-steroid
    secretion early in the course, indicating a primarily hypothalamic GnRH
    deficiency with a superimposed and progressive pituitary component. The
    result is delayed/absent puberty, lack of secondary sexual characteristics,
    and low gonadotropins and sex steroids.
  cell_types:
  - preferred_term: hypothalamic gonadotropin-releasing hormone neuron
    term:
      id: CL:0011111
      label: hypothalamic gonadotropin-releasing hormone neuron
  locations:
  - preferred_term: pituitary gland
    term:
      id: UBERON:0000007
      label: pituitary gland
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Defects were detected at the hypothalamic and pituitary levels of the reproductive endocrine axis."
    explanation: >
      Localizes the hypogonadotropic hypogonadism to combined hypothalamic and
      pituitary dysfunction.
  - reference: PMID:24113144
    reference_title: "Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the U box protein CHIP."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Loss of CHIP function in mice resulted in behavioral and reproductive impairments that mimic human ataxia and hypogonadism."
    explanation: >
      A CHIP-deficient mouse recapitulates the combined ataxia and reproductive
      (hypogonadism) phenotype.
  downstream:
  - target: Hypogonadism
    description: >
      Hypothalamic-pituitary-gonadal axis failure manifests clinically as
      hypogonadism.
  - target: Abnormality of the hypothalamus-pituitary axis
    description: >
      The endocrine lesion localizes to hypothalamic and pituitary levels.
  - target: Decreased fertility
    description: >
      Central hypogonadism reduces reproductive capacity.
  - target: Gynecomastia
    description: >
      Disrupted gonadal steroid signaling can manifest as gynecomastia.

- name: PNPLA6 / Neuropathy Target Esterase Phospholipid Dysfunction
  description: >
    A genetically distinct arm of the ataxia-hypogonadism continuum is caused by
    biallelic PNPLA6 variants. PNPLA6 encodes neuropathy target esterase (NTE),
    an endoplasmic-reticulum-localized lysophospholipase regulating membrane
    phospholipid homeostasis. PNPLA6 disorders span Boucher-Neuhauser syndrome
    (ataxia, hypogonadotropic hypogonadism, chorioretinal dystrophy), Gordon
    Holmes syndrome, spastic paraplegia type 39, Oliver-McFarlane, and
    Laurence-Moon syndromes, with age-dependent, multisystem manifestations
    affecting cerebellum, retina, peripheral nerves, and endocrine axes.
  genes:
  - preferred_term: PNPLA6
    term:
      id: hgnc:16268
      label: PNPLA6
  cellular_components:
  - preferred_term: endoplasmic reticulum
    term:
      id: GO:0005783
      label: endoplasmic reticulum
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A wide spectrum of neurodegenerative diseases has been associated with pathogenic variants in the PNPLA6 (patatin-like phospholipase domain-containing protein 6) gene, including spastic paraplegia type 39, Gordon-Holmes, Boucher-Neuhauser, Oliver-Mc Farlane, and Laurence-Moon syndromes."
    explanation: >
      Establishes PNPLA6 as a cause of the Gordon Holmes / Boucher-Neuhauser
      ataxia-hypogonadism continuum.
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PNPLA6 disorders span a phenotypic continuum characterized by variable combinations of cerebellar ataxia; upper motor neuron involvement manifesting as spasticity and/or brisk reflexes; chorioretinal dystrophy associated with variable degrees of reduced visual function; and hypogonadotropic hypogonadism"
    explanation: >
      GeneReviews defines the PNPLA6 phenotypic continuum encompassing the
      ataxia-hypogonadism syndromes.
  downstream:
  - target: Cerebellar and Hippocampal Neurodegeneration
    description: >
      PNPLA6 phospholipid dysfunction in cerebellar neurons causes progressive
      cerebellar atrophy and ataxia, with cerebellar atrophy documented by MRI
      in the majority of patients.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:35069422
      reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Cerebellar ataxia was observed in seven patients and spastic paraplegia in one patient. Progression of cerebellar symptoms was slow in all patients, who retained ambulation even after a mean disease duration of 15 years. Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII)."
      explanation: >
        Directly links PNPLA6 dysfunction to cerebellar neurodegeneration with
        progressive cerebellar atrophy and ataxia as the dominant phenotype.
  - target: Reproductive Endocrine Axis Dysfunction
    description: >
      PNPLA6 dysfunction also impairs the reproductive endocrine axis, producing
      hypogonadotropic hypogonadism in a substantial proportion of patients.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:25299038
      reference_title: "PNPLA6 Disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "hypogonadotropic hypogonadism (delayed puberty and lack of secondary sex characteristics). The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism"
      explanation: >
        GeneReviews confirms hypogonadotropic hypogonadism as a core feature of
        PNPLA6 disorders, connecting PNPLA6 dysfunction to reproductive endocrine
        axis impairment.
  - target: Abnormal electroretinogram
    description: >
      PNPLA6-related retinal dysfunction can be detected electrophysiologically.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Nystagmus
    description: >
      Retinal and cerebellar involvement can manifest with abnormal ocular
      movements.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Optic atrophy
    description: >
      PNPLA6-associated neuro-ophthalmologic degeneration can include optic
      atrophy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
  - target: Abnormality of retinal pigmentation
    description: >
      PNPLA6-related chorioretinal disease manifests with abnormal retinal
      pigmentation.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES

phenotypes:
- category: Neurologic
  name: Cerebellar ataxia
  description: >
    Progressive cerebellar ataxia (gait instability, incoordination) is a core
    and near-universal feature across all genetic subtypes.
  phenotype_term:
    preferred_term: Cerebellar ataxia
    term:
      id: HP:0001251
      label: Ataxia
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:24113144
    reference_title: "Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the U box protein CHIP."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gordon Holmes syndrome (GHS) is a rare Mendelian neurodegenerative disorder characterized by ataxia and hypogonadism."
    explanation: Ataxia is one of the two defining clinical features of the syndrome.
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All patients had progressive ataxia and dementia."
    explanation: All RNF216-mutation patients in the index cohort had progressive ataxia.

- category: Endocrine
  name: Hypogonadotropic hypogonadism
  description: >
    Central hypogonadotropic hypogonadism with low/inappropriately normal
    gonadotropins and low sex steroids, manifesting as delayed or absent puberty
    and absent secondary sexual characteristics. May be the first presentation,
    particularly in males.
  phenotype_term:
    preferred_term: Hypogonadotropic hypogonadism
    term:
      id: HP:0000044
      label: Hypogonadotropic hypogonadism
  evidence:
  - reference: PMID:39444518
    reference_title: "Hypogonadotropic Hypogonadism as First Presentation of the Severe Neuroendocrine Disorder Caused by RNF216."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Biallelic pathogenic variants in RNF216 cause a syndrome characterized by hypogonadotropic hypogonadism, cerebellar ataxia, chorea, and cognitive impairment, a combination first described as Gordon Holmes syndrome (MIM 212840)."
    explanation: Defines hypogonadotropic hypogonadism as a core feature of the RNF216 syndrome.
  - reference: PMID:39444518
    reference_title: "Hypogonadotropic Hypogonadism as First Presentation of the Severe Neuroendocrine Disorder Caused by RNF216."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "hypogonadotropic hypogonadism may be the initial manifestation of this severe neuroendocrine disorder, especially in males."
    explanation: Hypogonadism can precede neurologic signs as the presenting complaint.
- category: Endocrine
  name: Hypogonadism
  description: >
    Hypogonadism is a very frequent reproductive endocrine manifestation of
    cerebellar ataxia-hypogonadism syndrome.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Hypogonadism
    term:
      id: HP:0000135
      label: Hypogonadism
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000135 | Hypogonadism | Very frequent (99-80%)"
    explanation: Orphanet lists hypogonadism as a very frequent phenotype.
- category: Endocrine
  name: Abnormality of the hypothalamus-pituitary axis
  description: >
    Hypothalamic-pituitary axis dysfunction is a very frequent endocrine
    phenotype in the syndrome.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Abnormality of the hypothalamus-pituitary axis
    term:
      id: HP:0000864
      label: Abnormality of the hypothalamus-pituitary axis
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000864 | Abnormality of the hypothalamus-pituitary axis | Very frequent (99-80%)"
    explanation: Orphanet lists hypothalamus-pituitary axis abnormality as a very frequent phenotype.
- category: Reproductive
  name: Decreased fertility
  description: >
    Decreased fertility is a very frequent reproductive consequence of the
    hypogonadotropic hypogonadism phenotype.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Decreased fertility
    term:
      id: HP:0000144
      label: Decreased fertility
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000144 | Decreased fertility | Very frequent (99-80%)"
    explanation: Orphanet lists decreased fertility as a very frequent phenotype.
- category: Endocrine
  name: Gynecomastia
  description: >
    Gynecomastia is a very frequent endocrine phenotype in males with the
    syndrome.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Gynecomastia
    term:
      id: HP:0000771
      label: Gynecomastia
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000771 | Gynecomastia | Very frequent (99-80%)"
    explanation: Orphanet lists gynecomastia as a very frequent phenotype.

- category: Endocrine
  name: Delayed puberty
  description: >
    Delayed or absent puberty with lack of secondary sexual characteristics
    secondary to hypogonadotropic hypogonadism.
  phenotype_term:
    preferred_term: Delayed puberty
    term:
      id: HP:0000823
      label: Delayed puberty
  evidence:
  - reference: PMID:39444518
    reference_title: "Hypogonadotropic Hypogonadism as First Presentation of the Severe Neuroendocrine Disorder Caused by RNF216."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report 2 siblings who were referred due to absent or delayed puberty."
    explanation: Affected siblings presented with absent or delayed puberty.

- category: Endocrine
  name: Primary amenorrhea
  description: >
    Primary amenorrhea in affected females reflecting hypogonadotropic
    hypogonadism.
  phenotype_term:
    preferred_term: Primary amenorrhea
    term:
      id: HP:0000786
      label: Primary amenorrhea
  evidence:
  - reference: PMID:39444518
    reference_title: "Hypogonadotropic Hypogonadism as First Presentation of the Severe Neuroendocrine Disorder Caused by RNF216."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "His 15-year-old sister was referred due to primary amenorrhea."
    explanation: An affected female sibling presented with primary amenorrhea.

- category: Cognitive
  name: Cognitive decline and dementia
  description: >
    Progressive cognitive decline and dementia, prominent particularly in
    RNF216-related disease, with personality changes and memory loss; mental
    deterioration may include impaired attention, visuospatial abilities, and
    recall.
  phenotype_term:
    preferred_term: Dementia
    term:
      id: HP:0000726
      label: Dementia
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Dementia was also prominent, with personality changes and memory loss occurring at the onset of the disease"
    explanation: Dementia with personality changes and memory loss is prominent in RNF216-related disease.
  - reference: PMID:37161390
    reference_title: "A novel mutation in RNF216 gene in a Turkish case with Gordon Holmes syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gordon Holmes syndrome (GHS) is a rare autosomal recessive disorder characterized by hypogonadotropic hypogonadism, cognitive decline, and cerebellar ataxia."
    explanation: Cognitive decline is listed as one of the core GHS features.
- category: Cognitive
  name: Personality changes
  description: >
    Personality changes are an occasional neurobehavioral manifestation of
    cerebellar ataxia-hypogonadism syndrome.
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Personality changes
    term:
      id: HP:0000751
      label: Personality changes
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000751 | Personality changes | Occasional (29-5%)"
    explanation: Orphanet lists personality changes as an occasional phenotype.

- category: Neurologic
  name: Cerebellar atrophy
  description: >
    Cerebellar atrophy is a recurring MRI feature, often with vermian
    predominance in PNPLA6-related disease; pan-cerebellar atrophy is reported
    in RNF216 cases.
  phenotype_term:
    preferred_term: Cerebellar atrophy
    term:
      id: HP:0001272
      label: Cerebellar atrophy
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Brain MRI showed cerebellar atrophy in 6/8 patients, more pronounced in superior and dorsal vermis lobules (I to VII)."
    explanation: Cerebellar atrophy with vermian predominance was found in most PNPLA6 patients.
  - reference: PMID:37977846
    reference_title: "A novel mutation in RNF216 gene in an Indian case with Gordon Holmes syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "pan-cerebellar atrophy with bilateral cerebral white matter hyperintensities"
    explanation: Pan-cerebellar atrophy documented in an RNF216 case.

- category: Neurologic
  name: Cerebral white matter abnormality
  description: >
    Patchy subcortical/cerebral white-matter T2/FLAIR hyperintensities
    (leukoencephalopathy) are a consistent feature of RNF216-associated disease
    and may precede neurologic symptom onset.
  phenotype_term:
    preferred_term: Abnormal cerebral white matter morphology
    term:
      id: HP:0002500
      label: Abnormal cerebral white matter morphology
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The subcortical white matter contained patchy areas of hyperintensity on T2-weighted imaging and fluid-attenuated inversion recovery (FLAIR) imaging"
    explanation: Subcortical white-matter hyperintensities are documented across RNF216-mutation patients.
  - reference: PMID:39444518
    reference_title: "Hypogonadotropic Hypogonadism as First Presentation of the Severe Neuroendocrine Disorder Caused by RNF216."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "an extensive supratentorial leuko-encephalopathy"
    explanation: Extensive supratentorial leukoencephalopathy was found on MRI in an RNF216 case.

- category: Neurologic
  name: Chorea
  description: >
    Chorea and other movement disorders (parkinsonism, dystonia, tremor) occur
    in a subset of patients, particularly RNF216-related disease.
  phenotype_term:
    preferred_term: Chorea
    term:
      id: HP:0002072
      label: Chorea
  evidence:
  - reference: PMID:39444518
    reference_title: "Hypogonadotropic Hypogonadism as First Presentation of the Severe Neuroendocrine Disorder Caused by RNF216."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Biallelic pathogenic variants in RNF216 cause a syndrome characterized by hypogonadotropic hypogonadism, cerebellar ataxia, chorea, and cognitive impairment"
    explanation: Chorea is part of the RNF216 syndrome phenotype.

- category: Neurologic
  name: Dysarthria
  description: >
    Cerebellar dysarthria; dysarthria may be the initial neurologic symptom in
    some patients.
  phenotype_term:
    preferred_term: Dysarthria
    term:
      id: HP:0001260
      label: Dysarthria
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Dysarthria was the initial neurologic symptom in some patients"
    explanation: Dysarthria can be the presenting neurologic feature.
- category: Neurologic
  name: Abnormality of speech or vocalization
  description: >
    Abnormal speech or vocalization is a very frequent neurologic manifestation
    in the Orphanet phenotype profile.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Abnormality of speech or vocalization
    term:
      id: HP:0002167
      label: Abnormal speech pattern
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0002167 | Abnormality of speech or vocalization | Very frequent (99-80%)"
    explanation: Orphanet lists abnormality of speech or vocalization as a very frequent phenotype.

- category: Ophthalmologic
  name: Chorioretinal dystrophy
  description: >
    Chorioretinal dystrophy with reduced visual function characterizes the
    Boucher-Neuhauser end of the PNPLA6 continuum and distinguishes it from
    RNF216/STUB1-related Gordon Holmes syndrome.
  phenotype_term:
    preferred_term: Chorioretinal dystrophy
    term:
      id: HP:0001135
      label: Chorioretinal dystrophy
  evidence:
  - reference: PMID:33650466
    reference_title: "Chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia: Boucher-Neuhauser syndrome due to a homozygous (c.3524C>G (p.Ser1175Cys)) variant in PNPLA6 gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "neurologic, ophthalmologic, endocrine, and genetic evaluations established a diagnosis of BNHS"
    explanation: Chorioretinal dystrophy is a defining feature of the Boucher-Neuhauser (PNPLA6) form.
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "chorioretinal dystrophy associated with variable degrees of reduced visual function"
    explanation: GeneReviews documents chorioretinal dystrophy with reduced visual function in PNPLA6 disorders.
- category: Ophthalmologic
  name: Abnormal electroretinogram
  description: >
    Abnormal electroretinogram is a very frequent retinal-function phenotype in
    the syndrome's Orphanet profile.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Abnormal electroretinogram
    term:
      id: HP:0000512
      label: Abnormal electroretinogram
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000512 | Abnormal electroretinogram | Very frequent (99-80%)"
    explanation: Orphanet lists abnormal electroretinogram as a very frequent phenotype.
- category: Ophthalmologic
  name: Nystagmus
  description: >
    Nystagmus is a very frequent neuro-ophthalmologic phenotype.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Nystagmus
    term:
      id: HP:0000639
      label: Nystagmus
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000639 | Nystagmus | Very frequent (99-80%)"
    explanation: Orphanet lists nystagmus as a very frequent phenotype.
- category: Ophthalmologic
  name: Optic atrophy
  description: >
    Optic atrophy is a very frequent neuro-ophthalmologic phenotype.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Optic atrophy
    term:
      id: HP:0000648
      label: Optic atrophy
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0000648 | Optic atrophy | Very frequent (99-80%)"
    explanation: Orphanet lists optic atrophy as a very frequent phenotype.
- category: Ophthalmologic
  name: Abnormality of retinal pigmentation
  description: >
    Abnormal retinal pigmentation is a very frequent retinal phenotype in the
    Orphanet profile.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Abnormality of retinal pigmentation
    term:
      id: HP:0007703
      label: Abnormal retinal pigmentation
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007703 | Abnormality of retinal pigmentation | Very frequent (99-80%)"
    explanation: Orphanet lists abnormality of retinal pigmentation as a very frequent phenotype.

- category: Neurologic
  name: Peripheral axonal neuropathy
  description: >
    Peripheral neuropathy of axonal type (reduced distal reflexes, diminished
    vibratory sensation, distal muscle wasting) is a common but less frequent
    feature, especially in PNPLA6-related disease.
  phenotype_term:
    preferred_term: Peripheral axonal neuropathy
    term:
      id: HP:0003477
      label: Peripheral axonal neuropathy
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "peripheral axonal neuropathy (4/8)"
    explanation: Peripheral axonal neuropathy occurred in half of the PNPLA6 cohort.

- category: Neurologic
  name: Hyperreflexia
  description: >
    Upper motor neuron involvement manifesting as brisk reflexes/spasticity is
    seen in the PNPLA6 continuum and is a variable feature of Gordon Holmes
    syndrome.
  phenotype_term:
    preferred_term: Hyperreflexia
    term:
      id: HP:0001347
      label: Hyperreflexia
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Gordon Holmes syndrome (cerebellar ataxia, hypogonadotropic hypogonadism, and – to a variable degree – brisk reflexes)"
    explanation: GeneReviews lists variable brisk reflexes within the Gordon Holmes cluster of PNPLA6 disorders.
- category: Neurologic
  name: Hemiplegia/hemiparesis
  description: >
    Hemiplegia or hemiparesis is a frequent motor phenotype in Orphanet's
    syndrome profile.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Hemiplegia/hemiparesis
    term:
      id: HP:0004374
      label: Hemiplegia/hemiparesis
  evidence:
  - reference: ORPHA:1173
    reference_title: "Cerebellar ataxia-hypogonadism syndrome (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0004374 | Hemiplegia/hemiparesis | Frequent (79-30%)"
    explanation: Orphanet lists hemiplegia/hemiparesis as a frequent phenotype.

genetic:
- name: RNF216 biallelic pathogenic variants
  gene_term:
    preferred_term: RNF216
    term:
      id: hgnc:21698
      label: RNF216
  association: Causative biallelic (and digenic with OTUD4) pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:37161390
      reference_title: "A novel mutation in RNF216 gene in a Turkish case with Gordon Holmes syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Gordon Holmes syndrome (GHS) is a rare autosomal recessive disorder"
      explanation: Confirms autosomal recessive inheritance of RNF216-related GHS.
  notes: >
    RNF216 is the most frequent cause. Reported variants include splice-site
    (c.2061G>A), frameshift (c.1860_1861dupCT, p.Cys621SerfsTer56), nonsense, and
    missense (e.g., p.R751C) changes. The original NEJM kindred carried a digenic
    homozygous RNF216/OTUD4 genotype.
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The syndrome of hypogonadotropic hypogonadism, ataxia, and dementia can be caused by inactivating mutations in RNF216 or by the combination of mutations in RNF216 and OTUD4."
    explanation: Establishes RNF216 (and digenic RNF216/OTUD4) as the genetic cause.
  - reference: PMID:27441066
    reference_title: "Ataxia and Hypogonadotropic Hypogonadism with Intrafamilial Variability Caused by RNF216 Mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We identified a novel splicing variant in RNF216 that is likely to abolish the canonical splice site at the junction of exon/intron 13 (NM_207111.3:c.2061G>A)."
    explanation: A novel RNF216 splice-site variant causes GHS, illustrating allelic heterogeneity.

- name: OTUD4 (digenic with RNF216) pathogenic variants
  gene_term:
    preferred_term: OTUD4
    term:
      id: hgnc:24949
      label: OTUD4
  association: Digenic contributor with RNF216
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:23656588
      reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family."
      explanation: Homozygous OTUD4 variants in a consanguineous kindred indicate recessive (digenic) inheritance.
  notes: >
    OTUD4 encodes a deubiquitinase that partners with the RNF216 E3 ligase.
    A homozygous OTUD4 variant acted digenically/epistatically with RNF216 in the
    original consanguineous kindred; zebrafish double knockdown exacerbated the
    cerebellar phenotype.
  evidence:
  - reference: PMID:23656588
    reference_title: "Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Digenic homozygous mutations in RNF216 and OTUD4, which encode a ubiquitin E3 ligase and a deubiquitinase, respectively, were found in three affected siblings in a consanguineous family."
    explanation: Documents OTUD4 as a digenic contributor with RNF216.

- name: STUB1 (CHIP) biallelic pathogenic variants
  gene_term:
    preferred_term: STUB1
    term:
      id: hgnc:11427
      label: STUB1
  association: Causative biallelic pathogenic variants
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:24113144
      reference_title: "Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the U box protein CHIP."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "We performed exome sequencing in a family with two of three siblings afflicted with ataxia and hypogonadism and identified a homozygous mutation in STUB1"
      explanation: A homozygous STUB1 variant in affected siblings indicates autosomal recessive inheritance.
  notes: >
    Homozygous STUB1 c.737C>T (p.Thr246Met) causes loss of CHIP E3 ubiquitin
    ligase activity producing ataxia with hypogonadism consistent with GHS.
  evidence:
  - reference: PMID:24113144
    reference_title: "Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the U box protein CHIP."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "identified a homozygous mutation in STUB1 (NM_005861) c.737C→T, p.Thr246Met, a gene that encodes the protein CHIP (C-terminus of HSC70-interacting protein)."
    explanation: Identifies a homozygous STUB1/CHIP variant causing GHS.

- name: PNPLA6 biallelic pathogenic variants
  gene_term:
    preferred_term: PNPLA6
    term:
      id: hgnc:16268
      label: PNPLA6
  association: Causative biallelic pathogenic variants (Gordon Holmes / Boucher-Neuhauser continuum)
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:25299038
      reference_title: "PNPLA6 Disorders."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "PNPLA6 disorders are inherited in an autosomal recessive manner."
      explanation: GeneReviews confirms autosomal recessive inheritance of PNPLA6 disorders.
  notes: >
    PNPLA6 (neuropathy target esterase) variants cause an allelic continuum that
    includes Gordon Holmes syndrome and Boucher-Neuhauser syndrome. Reported
    variants include missense changes such as c.3524C>G (p.Ser1175Cys). PNPLA6
    variants were found in 8/292 (2.7%) of an ataxia/spastic paraplegia cohort.
  evidence:
  - reference: PMID:35069422
    reference_title: "Multifaceted and Age-Dependent Phenotypes Associated With Biallelic PNPLA6 Gene Variants: Eight Novel Cases and Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We identified six novel and four recurrent PNPLA6 gene variants in eight patients (2.7%)."
    explanation: Quantifies PNPLA6 variant detection in an ataxia/spastic paraplegia screening cohort.
  - reference: PMID:33650466
    reference_title: "Chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia: Boucher-Neuhauser syndrome due to a homozygous (c.3524C>G (p.Ser1175Cys)) variant in PNPLA6 gene."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We identified a missense homozygous variant (c.3524 C > G (p.Ser1175Cys)) in the PNPLA6 gene, which explains the phenotype of the patient"
    explanation: A homozygous PNPLA6 missense variant causes Boucher-Neuhauser within the continuum.

treatments:
- name: Sex Hormone Replacement Therapy
  description: >
    Hormone replacement therapy for hypogonadotropic hypogonadism (testosterone
    in males, estrogen/progesterone in females) is given at the expected time of
    puberty to induce and maintain secondary sexual characteristics and
    menstruation and to support fertility planning. In RNF216 case series,
    testosterone therapy improved secondary sexual characteristics but did not
    alter neurologic signs.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Hormone Replacement Therapy
    term:
      id: NCIT:C15599
      label: Hormone Replacement Therapy
    therapeutic_agent:
    - preferred_term: testosterone
      term:
        id: CHEBI:17347
        label: testosterone
    - preferred_term: estradiol
      term:
        id: CHEBI:23965
        label: estradiol
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hypogonadotropic hypogonadism. Hormone replacement therapy at the expected time of puberty."
    explanation: GeneReviews recommends hormone replacement therapy for the hypogonadotropic hypogonadism.

- name: Multidisciplinary Supportive and Rehabilitative Care
  description: >
    Management is symptomatic and individually tailored: continuous training of
    speech and swallowing, fine-motor skills, gait, and balance for ataxia;
    physical therapy and assistive devices for spasticity; low-vision aids for
    chorioretinal dystrophy; and periodic multidisciplinary reevaluation. No
    disease-modifying therapy exists.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Management is symptomatic and individually tailored."
    explanation: GeneReviews describes symptomatic, individually tailored supportive management.

- name: Physical Therapy
  description: >
    Physical therapy, assistive walking devices, and ankle-foot orthotics to
    improve strength and agility and prevent contractures, particularly when
    spasticity is present.
  treatment_term:
    preferred_term: Physical Therapy
    term:
      id: NCIT:C15302
      label: Physical Therapy
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Interventions to improve strength and agility and to prevent contractures, such as physical therapy, assistive walking devices and/or ankle-foot orthotics"
    explanation: GeneReviews recommends physical therapy and assistive devices for spasticity.

- name: Genetic Counseling
  description: >
    Genetic counseling for affected families. Once the pathogenic variants are
    identified, carrier testing, prenatal testing, and preimplantation genetic
    testing are possible.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:25299038
    reference_title: "PNPLA6 Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "carrier testing for at-risk relatives, prenatal testing for a pregnancy at increased risk, and preimplantation genetic testing are possible."
    explanation: GeneReviews outlines genetic counseling and reproductive testing options.

datasets: []
📚

References & Deep Research

References

1
PMID:25299038
PNPLA6 Disorders.
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
Disease Characteristics Research Template
Edison Scientific Literature 55 citations 2026-06-04T16:07:15.056939

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Cerebellar Ataxia-Hypogonadism Syndrome
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Cerebellar Ataxia-Hypogonadism Syndrome covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
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  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
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  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
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  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
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  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
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  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

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  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Cerebellar Ataxia–Hypogonadism Syndrome (Gordon Holmes syndrome spectrum): comprehensive disease characteristics report

Executive summary

Cerebellar ataxia–hypogonadism syndrome is a rare, genetically heterogeneous, Mendelian neurodegenerative–neuroendocrine disorder classically described as Gordon Holmes syndrome (GHS), with a core association of progressive cerebellar ataxia and hypogonadotropic hypogonadism (HH) and frequent additional features such as cognitive decline/dementia and other movement disorders. Multiple genes converge on protein homeostasis/ubiquitin signaling (e.g., RNF216, OTUD4, STUB1/CHIP) or phospholipid metabolism (PNPLA6), producing overlapping syndromic entities such as GHS and Boucher–Neuhauser syndrome (BNHS) (ataxia–HH–chorioretinal dystrophy). Recent case reports (2023–2024) expand the phenotype (e.g., pituitary/white-matter imaging findings; endocrine-first presentations) and add mechanistic insight from new animal model work implicating microglia/neuroinflammation in RNF216-related disease. (shi2014ataxiaandhypogonadism pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2, george2024gordonholmessyndrome pages 1-2, nanetti2022multifacetedandagedependent pages 1-2)

1. Disease information

1.1 Definition and current understanding

Gordon Holmes syndrome (GHS) is defined in primary literature as a Mendelian neurodegenerative disorder characterized by ataxia and hypogonadism (“Gordon Holmes syndrome (GHS) is a rare Mendelian neurodegenerative disorder characterized by ataxia and hypogonadism.”). (shi2014ataxiaandhypogonadism pages 1-2)

A 2024 endocrine case report explicitly situates the disorder as a neuroendocrine condition in which HH may precede neurodegeneration and notes the phenotype combination “first described as Gordon Holmes syndrome.” (rochtus2024hypogonadotropichypogonadismas pages 1-2)

Related/overlapping syndromes within the ataxia–hypogonadism spectrum include: - Boucher–Neuhauser syndrome (BNHS/BNS) (ataxia + HH + chorioretinal dystrophy) due to PNPLA6 variants. (liampas2024twocasereports pages 5-8, deik2014compoundheterozygouspnpla6 pages 1-2) - 4H syndrome (hypodontia, hypomyelination, ataxia, hypogonadotropic hypogonadism) reported in association with RNF216 and also POLR3-related leukodystrophy genes in differential lists. (wu2022gordonholmessyndrome pages 7-11, calandra2019gordonholmessyndrome pages 1-4)

1.2 Key identifiers and synonyms

  • OMIM/MIM: The syndrome is labeled Gordon Holmes syndrome, MIM #212840 in 2023 and 2024 sources. (kallupurakkal2023anovelmutation pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2)
  • BNHS MIM: Boucher–Neuhauser syndrome, MIM #215470; PNPLA6 gene, MIM #603197. (deik2014compoundheterozygouspnpla6 pages 1-2)
  • Other curated identifiers (MONDO, Orphanet, MeSH, ICD-10/ICD-11): Not present in the retrieved full-text evidence for this run; therefore not reported here. (No direct evidence found in provided corpus)

1.3 Synonyms / alternative names

  • “Gordon Holmes syndrome” is used as the syndromic name for the ataxia–hypogonadism association; the broader entry term in many contexts is “ataxia–hypogonadotropic hypogonadism” (as used in clinical descriptions and titles). (alqwaifly2016ataxiaandhypogonadotropic pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2)

1.4 Evidence source type

The disease characterization in this report is derived from: - Primary human studies/case reports/series (NEJM 2013; multiple 2014–2024 case reports and cohorts). (margolin2013ataxiadementiaand pages 9-11, kallupurakkal2023anovelmutation pages 1-2, celik2023anovelmutation pages 1-2, nanetti2022multifacetedandagedependent pages 1-2) - Model organism studies (Rnf216 knockout mice; CHIP/STUB1 functional work and mouse phenotyping). (george2024gordonholmessyndrome pages 1-2, shi2014ataxiaandhypogonadism pages 1-2)

2. Etiology

2.1 Disease causal factors (genetic/mechanistic)

This is primarily a genetic (Mendelian) disorder with multiple causal genes: - RNF216 biallelic pathogenic variants cause a syndrome characterized by HH with neurodegeneration (ataxia ± chorea ± cognitive impairment), historically termed GHS. (rochtus2024hypogonadotropichypogonadismas pages 1-2) - STUB1 (CHIP) biallelic variants can cause ataxia with HH consistent with GHS, attributed to impaired ubiquitin ligase activity and protein quality control. (shi2014ataxiaandhypogonadism pages 1-2) - PNPLA6 biallelic variants cause overlapping disorders including GHS and BNHS with endocrine and neuro-ophthalmologic manifestations. (nanetti2022multifacetedandagedependent pages 1-2, deik2014compoundheterozygouspnpla6 pages 1-2)

A key mechanistic theme is disordered ubiquitination/protein homeostasis in RNF216/OTUD4/STUB1-related disease. (margolin2013ataxiadementiaand pages 9-11, shi2014ataxiaandhypogonadism pages 1-2)

2.2 Risk factors

  • Genetic risk factors: biallelic pathogenic variants in RNF216, STUB1, PNPLA6; in some families digenic/oligogenic inheritance has been reported (RNF216 with OTUD4; and other interacting genes in reviews). (margolin2013ataxiadementiaand pages 9-11, wu2022gordonholmessyndrome pages 1-4)

  • Family history/consanguinity: multiple reports highlight homozygous variants and parental heterozygosity consistent with recessive inheritance; consanguinity is frequent in recessive ataxia syndromes and reported in PNPLA6 and RNF216 cases. (deik2014compoundheterozygouspnpla6 pages 1-2, calandra2019gordonholmessyndrome pages 1-4, canbek2024…>g pages 2-4)

  • Environmental risk factors: not established in the retrieved evidence; one animal model paper notes that “compound mutations or environmental factors may worsen phenotype” as a general consideration rather than a proven interaction. (george2024gordonholmessyndrome pages 16-17)

2.3 Protective factors

No protective genetic or environmental factors were identified in the retrieved evidence. (No direct evidence found)

2.4 Gene–environment interactions

Not established in the retrieved evidence beyond speculative mention that environmental factors could modulate phenotype severity. (george2024gordonholmessyndrome pages 16-17)

3. Phenotypes

3.1 Core neurologic and endocrine phenotypes

Across the GHS spectrum, commonly reported features include: - Cerebellar ataxia (gait instability, dysarthria, nystagmus) with cerebellar atrophy on MRI. (shi2014ataxiaandhypogonadism pages 1-2) - Hypogonadotropic hypogonadism presenting as delayed/absent puberty, primary amenorrhea, low gonadotropins/sex steroids; HH may be an initial presentation in RNF216-related disease. (rochtus2024hypogonadotropichypogonadismas pages 1-2, alqwaifly2016ataxiaandhypogonadotropic pages 1-2) - Cognitive decline/dementia is frequently described in RNF216-related and some STUB1-related disease. (margolin2013ataxiadementiaand pages 9-11, celik2023anovelmutation pages 1-2) - Additional movement disorders can include chorea, parkinsonism, dystonia, and tremor in some cases. (rochtus2024hypogonadotropichypogonadismas pages 1-2, celik2023anovelmutation pages 1-2, kallupurakkal2023anovelmutation pages 1-2)

3.2 Phenotype frequency data (recent cohort statistics)

Because the term “Cerebellar ataxia–hypogonadism syndrome” encompasses multiple genes, the most quantitative frequency data in the retrieved corpus come from a PNPLA6 cohort: - In Nanetti et al. 2022 (probe-based panel screening of 292 ataxia/spastic paraplegia patients), PNPLA6 variants were found in 8/292 (2.7%); among these 8: - Cerebellar ataxia: 7/8 - Hypogonadotropic hypogonadism: 5/8 - Cerebellar atrophy on MRI: 6/8 (with vermian predominance) - Peripheral axonal neuropathy: 4/8 - Cognitive impairment: 3/8 - Chorioretinal dystrophy: 2/8 - Growth hormone deficiency: 2/8 - Vestibular areflexia with reduced VVOR: 1/8 - Natural history: slow progression, with retained ambulation after a mean disease duration of 15 years. (nanetti2022multifacetedandagedependent pages 1-2)

BNHS-specific literature review frequency data (primarily visual phenotype) were summarized in a 2021 ophthalmic genetics report (review of molecularly confirmed PNPLA6-BNHS): - Chorioretinal dystrophy: 96.4% in the reviewed BNHS cases. - First presenting symptoms in their compiled cases included delayed puberty 32.1% and ataxia 28.6%. (dogan2021chorioretinaldystrophyhypogonadotropic pages 1-3)

3.3 Onset, severity, progression

  • RNF216-related GHS: neurologic features often emerge in adolescence/young adulthood; HH may precede neurologic features and can be the presenting complaint (endocrine-first). (rochtus2024hypogonadotropichypogonadismas pages 1-2)
  • PNPLA6-related disease: age-dependent manifestation is emphasized; in Nanetti et al. 2022, infantile/juvenile onset occurred in 6/8, with adult onset in 2/8, and symptom type varied by age (retinal symptoms early, HH juvenile, ataxia adult). (nanetti2022multifacetedandagedependent pages 1-2)

3.4 Quality-of-life impact

Direct QoL instrument data (EQ-5D, SF-36, PROMIS) were not identified in the retrieved evidence. Nonetheless, reported features imply substantial functional impact via progressive gait ataxia, endocrine dysfunction (pubertal failure/infertility), neurocognitive decline, and visual loss (in BNHS). (liampas2024twocasereports pages 5-8, rochtus2024hypogonadotropichypogonadismas pages 1-2, shi2014ataxiaandhypogonadism pages 1-2)

3.5 Suggested HPO terms (examples)

(These are ontology suggestions for curation; they are not claims of prevalence beyond the cited clinical evidence.) - Cerebellar ataxia HP:0001251 - Dysarthria HP:0001260 - Nystagmus HP:0000639 (incl. gaze-evoked) - Cerebellar atrophy HP:0001272 - Hypogonadotropic hypogonadism HP:0000046 - Delayed puberty HP:0000821 / Primary amenorrhea HP:0000786 - Cognitive impairment HP:0100543 / Dementia HP:0000726 - Chorea HP:0002072 - White matter abnormalities / leukoencephalopathy HP:0002500 - Chorioretinal dystrophy HP:0000602 / Vision loss HP:0000572 - Peripheral axonal neuropathy HP:0003477

4. Genetic / molecular information

4.1 Causal genes (current evidence-backed set)

Genes directly implicated in the retrieved primary literature include RNF216, OTUD4 (digenic with RNF216), STUB1 (CHIP), PNPLA6. (margolin2013ataxiadementiaand pages 9-11, shi2014ataxiaandhypogonadism pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2, nanetti2022multifacetedandagedependent pages 1-2)

Additional genes are listed as associated with ataxia–hypogonadism overlap (e.g., POLR3A/POLR3B/POLR1C in 4H syndrome context) but without variant-level evidence in the retrieved snippets. (calandra2019gordonholmessyndrome pages 1-4, wu2022gordonholmessyndrome pages 7-11)

4.2 Pathogenic variants and types (examples from evidence)

Representative variants reported in the retrieved evidence include: - RNF216: splice-site (c.2061G>A), frameshift (c.1860_1861dupCT; c.591_592insTG), nonsense (c.1549C>T), missense (c.2042C>T p.P606L). (alqwaifly2016ataxiaandhypogonadotropic pages 1-2, celik2023anovelmutation pages 1-2, kallupurakkal2023anovelmutation pages 1-2, wu2022gordonholmessyndrome pages 7-11, calandra2019gordonholmessyndrome pages 1-4) - STUB1: homozygous missense c.737C>T (p.Thr246Met) causing loss of ubiquitin ligase activity. (shi2014ataxiaandhypogonadism pages 1-2) - PNPLA6: missense variants including c.3524C>G (p.Ser1175Cys), c.3323G>A (p.Arg1108Gln), c.3380C>G (p.Ser1127Cys). (dogan2021chorioretinaldystrophyhypogonadotropic pages 1-3, liampas2024twocasereports pages 1-5, canbek2024…>g pages 2-4)

Variant classification (ACMG) is reported variably; e.g., a 2024 PNPLA6 report presents p.Arg1108Gln as a VUS in that family context. (liampas2024twocasereports pages 5-8)

4.3 Functional consequences and pathways

  • RNF216 encodes an RBR-class E3 ubiquitin ligase, with pathogenic variants clustering in the RBR domain or C-terminal extension and presumed to disrupt E3 activity in GHS. (rochtus2024hypogonadotropichypogonadismas pages 1-2, wu2022gordonholmessyndrome pages 1-4)
  • STUB1/CHIP: “CHIP plays a central role in regulating protein quality control” and the p.Thr246Met mutation causes “a loss of ubiquitin ligase activity,” linking impaired ubiquitination/proteostasis to ataxia and HH. (shi2014ataxiaandhypogonadism pages 1-2)
  • PNPLA6 encodes neuropathy target esterase (NTE), an ER-localized lysophospholipase; PNPLA6-related phenotypes span neurodegeneration, endocrine dysfunction, and retinal degeneration. (nanetti2022multifacetedandagedependent pages 1-2, deik2014compoundheterozygouspnpla6 pages 1-2)

4.4 Modifier genes / oligogenicity

A landmark human genetics study reported a digenic/epistatic interaction between RNF216 and OTUD4, with experimental support for more severe phenotypes after simultaneous knockdown, and noted the potential for oligogenicity to be increasingly recognized with exome sequencing. (margolin2013ataxiadementiaand pages 9-11)

A later review of RNF216-related cases reports both monogenic recessive and oligogenic patterns involving OTUD4 or other genes. (wu2022gordonholmessyndrome pages 1-4)

4.5 Epigenetics and chromosomal abnormalities

No disease-specific epigenetic mechanisms or recurrent chromosomal abnormalities were identified in the retrieved evidence. (No direct evidence found)

5. Environmental information

No established toxin, lifestyle, radiation, or infectious triggers were identified in the retrieved evidence as causal for this Mendelian syndrome, though phenotype variability may be influenced by non-genetic modifiers in principle. (george2024gordonholmessyndrome pages 16-17)

6. Mechanism / pathophysiology

6.1 Ubiquitin–proteasome / proteostasis mechanisms (RNF216, OTUD4, STUB1)

Primary human genetics and functional evidence link disordered ubiquitination to combined neurodegeneration and HH: - NEJM 2013 describes neuroimaging (cerebellar/cortical atrophy and white-matter hyperintensities) and neuropathology featuring ubiquitin-immunoreactive intranuclear inclusions, implicating ubiquitin pathway dysfunction in the disease biology. (margolin2013ataxiadementiaand pages 9-11) - STUB1/CHIP work demonstrates that introducing a disease mutation into CHIP leads to loss of E3 ubiquitin ligase activity, and notes that loss of CHIP function in mice causes behavioral and reproductive impairments mimicking human phenotypes. (shi2014ataxiaandhypogonadism pages 1-2)

Causal chain (conceptual): biallelic loss-of-function (or loss of critical E3 function) in ubiquitin pathway enzymes → impaired ubiquitination/protein quality control (and possibly autophagy regulation) → accumulation of toxic proteins/inclusions and neural circuit dysfunction → cerebellar and extra-cerebellar neurodegeneration (ataxia, cognitive decline, movement disorders) plus hypothalamic–pituitary–gonadal axis dysfunction (HH). (margolin2013ataxiadementiaand pages 9-11, shi2014ataxiaandhypogonadism pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2)

6.2 Neuroinflammation and microglia (recent 2024 model evidence)

A 2024 Rnf216 knockout mouse study reports sex- and age-dependent microglial alterations in hippocampus/cortex and proposes microglial activation/neuroinflammation as a mechanistic link preceding learning deficits; endocrine changes were also observed in males (elevated FSH, reduced inhibin B; increased IL‑1β). (george2024gordonholmessyndrome pages 16-17)

This work represents a recent development (2024) suggesting potential mechanistic intermediates (microglia, cytokine signaling) that may be upstream contributors to cognitive impairment in RNF216-related disease. (george2024gordonholmessyndrome pages 16-17)

6.3 Lipid/phospholipase biology (PNPLA6)

PNPLA6-associated ataxia–HH syndromes are linked to dysfunction of neuropathy target esterase (lysophospholipase/phospholipid metabolism) with multi-system involvement (cerebellum, retina, peripheral nerves, endocrine axes). (nanetti2022multifacetedandagedependent pages 1-2, deik2014compoundheterozygouspnpla6 pages 1-2)

6.4 Suggested GO biological process / cellular component terms (examples)

(ontology suggestions for curation) - GO:0006511 ubiquitin-dependent protein catabolic process - GO:0016567 protein ubiquitination - GO:0006914 autophagy (for RNF216/STUB1-related discussions) (celik2023anovelmutation pages 1-2, shi2014ataxiaandhypogonadism pages 1-2) - GO:0006954 inflammatory response / GO:0001775 cell activation (microglia-related) (george2024gordonholmessyndrome pages 16-17) - GO cellular component: GO:0005783 endoplasmic reticulum (PNPLA6/NTE is ER-localized) (nanetti2022multifacetedandagedependent pages 1-2)

6.5 Suggested CL cell types (examples)

  • Microglia CL:0000129 (implicated in Rnf216 KO phenotypes) (george2024gordonholmessyndrome pages 16-17)
  • Purkinje cell CL:0000121 (relevant to cerebellar degeneration/ataxia; not directly measured in retrieved evidence)
  • GnRH neuron CL:0000543 (relevant to HH mechanism; endocrine physiology testing supports central HH) (margolin2013ataxiadementiaand pages 9-11, shi2014ataxiaandhypogonadism pages 1-2)

7. Anatomical structures affected

7.1 Organ/system level (evidence-backed)

  • Central nervous system: cerebellum (cerebellar atrophy), cerebral cortex, and cerebral white matter (hyperintensities/leukoencephalopathy). (shi2014ataxiaandhypogonadism pages 1-2, margolin2013ataxiadementiaand pages 9-11, rochtus2024hypogonadotropichypogonadismas pages 1-2)
  • Endocrine/reproductive axis: hypothalamic–pituitary–gonadal axis dysfunction causing HH; pituitary anomalies (e.g., hypoplastic posterior pituitary, partial empty sella) reported in some RNF216 cases. (rochtus2024hypogonadotropichypogonadismas pages 1-2, alqwaifly2016ataxiaandhypogonadotropic pages 1-2)
  • Eye/retina: chorioretinal dystrophy in BNHS/BNS. (liampas2024twocasereports pages 5-8, dogan2021chorioretinaldystrophyhypogonadotropic pages 1-3)
  • Peripheral nervous system: peripheral axonal neuropathy in PNPLA6 cohorts/cases. (nanetti2022multifacetedandagedependent pages 1-2, liampas2024twocasereports pages 1-5)

7.2 Suggested UBERON terms (examples)

  • Cerebellum UBERON:0002037
  • Cerebral cortex UBERON:0000956
  • White matter UBERON:0002319
  • Pituitary gland UBERON:0000007
  • Retina UBERON:0000966
  • Hypothalamus UBERON:0001898

7.3 Subcellular localization (from evidence)

  • PNPLA6/NTE is described as ER-localized in the PNPLA6 cohort paper. (nanetti2022multifacetedandagedependent pages 1-2)

8. Temporal development

  • Onset: often adolescent/young adult for RNF216 and classic GHS, but endocrine-first (pubertal delay) presentations are increasingly recognized. (rochtus2024hypogonadotropichypogonadismas pages 1-2)
  • Progression: neurodegeneration is typically progressive; PNPLA6 cohort data indicate slow progression with preserved ambulation after long durations in many patients. (nanetti2022multifacetedandagedependent pages 1-2)
  • Course patterns: generally chronic progressive; episodic/remitting patterns not described in retrieved evidence. (No direct evidence found)

9. Inheritance and population

9.1 Inheritance patterns

  • Predominantly autosomal recessive with biallelic pathogenic variants (RNF216, STUB1, PNPLA6). (rochtus2024hypogonadotropichypogonadismas pages 1-2, shi2014ataxiaandhypogonadism pages 1-2, nanetti2022multifacetedandagedependent pages 1-2)
  • Digenic/oligogenic inheritance is documented in RNF216-related disease (RNF216 with OTUD4; reported oligogenic fraction in a case-collection analysis). (margolin2013ataxiadementiaand pages 9-11, wu2022gordonholmessyndrome pages 1-4)

9.2 Population data (epidemiology)

No prevalence/incidence estimates were identified in the retrieved evidence. The condition is consistently described as rare, and available data are largely case-based or small cohorts. (shi2014ataxiaandhypogonadism pages 1-2, kallupurakkal2023anovelmutation pages 1-2)

9.3 Sex ratio and demographics

A review of RNF216-related disorders reported male predominance in the GHS subgroup compared with Huntington-like presentations and noted sex differences in pubertal development problems. (wu2022gordonholmessyndrome pages 1-4)

10. Diagnostics

10.1 Clinical testing (endocrine and neurologic)

Common diagnostic components include: - Endocrine labs: gonadotropins (LH/FSH) and sex steroids (testosterone/estradiol); HH characterized by low/inappropriately normal LH/FSH with low sex steroids. (gonzalez‐latapi2021movementdisordersassociated pages 2-4, rochtus2024hypogonadotropichypogonadismas pages 1-2) - GnRH stimulation testing: in STUB1-related GHS sisters, GnRH stimulation demonstrated pituitary responsiveness; imaging and hormone details are summarized in Shi et al. with tabulated data. (shi2014ataxiaandhypogonadism pages 1-2, shi2014ataxiaandhypogonadism media 6ceea760)

10.2 Imaging

  • Brain MRI: cerebellar atrophy is a recurring feature (e.g., “remarkable atrophy of the cerebellum” in STUB1 sisters); white-matter hyperintensities/leukoencephalopathy and corpus callosum thinning have been reported particularly in RNF216-related disease. (shi2014ataxiaandhypogonadism pages 1-2, margolin2013ataxiadementiaand pages 9-11, calandra2019gordonholmessyndrome pages 1-4, rochtus2024hypogonadotropichypogonadismas pages 1-2)

10.3 Genetic testing approaches

  • WES / exome-based diagnosis: used across multiple reports to identify homozygous/compound heterozygous variants in RNF216, STUB1, and PNPLA6. (shi2014ataxiaandhypogonadism pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2, liampas2024twocasereports pages 1-5)

10.4 Differential diagnosis

A 2024 PNPLA6-BNS case report lists differential diagnoses including Gordon Holmes syndrome, Woodhouse–Sakati syndrome, and mitochondrial disorders; BNS is distinguished by chorioretinal dystrophy and often absent/mild cognitive dysfunction. (liampas2024twocasereports pages 5-8)

11. Outcome / prognosis

Robust survival estimates were not identified in the retrieved evidence. Available natural history data suggest: - PNPLA6-associated disease can show slow progression with long-term ambulation preserved in many patients (mean duration 15 years in one cohort). (nanetti2022multifacetedandagedependent pages 1-2) - RNF216 and STUB1-related presentations may include substantial cognitive decline and multisystem complications in some families, implying variable but potentially severe outcomes. (celik2023anovelmutation pages 1-2, shi2014ataxiaandhypogonadism pages 1-2)

12. Treatment and current applications (real-world implementation)

12.1 Disease-modifying therapy

No disease-modifying therapy is described in the retrieved evidence for GHS/BNHS; management is largely supportive/symptom-directed. (liampas2024twocasereports pages 5-8)

12.2 Symptomatic and supportive care

Evidence-backed management elements include: - Hormone replacement/substitution for HH to induce/maintain secondary sexual characteristics and menstruation/fertility planning (e.g., PNPLA6-related GHS case report describes hormone replacement establishing menstruation and secondary sexual features; RNF216 case series notes testosterone therapy improved secondary sexual characteristics but not neurologic signs). (canbek2024…>g pages 2-4, alqwaifly2016ataxiaandhypogonadotropic pages 1-2) - Multidisciplinary supportive care for BNS: visual aids, speech/occupational/physiotherapy, genetic and psychosocial counseling. (liampas2024twocasereports pages 5-8)

12.3 Suggested MAXO terms (examples)

(ontology suggestions) - Hormone replacement therapy MAXO:0000647 (sex steroid replacement) - Genetic counseling MAXO:0000747 - Physical therapy MAXO:0000011 - Occupational therapy MAXO:0000010 - Speech therapy MAXO:0000129 - Assistive devices for mobility/vision MAXO:0000880 (broad)

13. Prevention

Primary prevention is not applicable for an inherited Mendelian disorder in the usual sense. Preventive strategies in practice focus on: - Genetic counseling and family planning in affected families. (liampas2024twocasereports pages 5-8) - Cascade testing of at-risk relatives (implied by carrier-parent findings in recessive families). (rochtus2024hypogonadotropichypogonadismas pages 1-2, liampas2024twocasereports pages 1-5)

14. Other species / natural disease

No naturally occurring non-human disease analogs were identified in the retrieved evidence. (No direct evidence found)

15. Model organisms

15.1 RNF216 models (2024 development)

A 2024 eNeuro study used constitutive Rnf216 knockout mice and found age- and sex-dependent abnormalities in learning strategies and microglia, providing a mechanistic foothold for RNF216-related GHS biology beyond descriptive genetics. (george2024gordonholmessyndrome pages 1-2, george2024gordonholmessyndrome pages 16-17)

15.2 STUB1/CHIP models

STUB1/CHIP functional work reports that CHIP loss of function in mice results in behavioral and reproductive impairments that mimic human ataxia and hypogonadism. (shi2014ataxiaandhypogonadism pages 1-2)

Recent developments and expert analysis (prioritizing 2023–2024)

  1. 2023 RNF216 case expansion: A 2023 BMC Medical Genomics case report reiterates core GHS features and documents expanded movement-disorder manifestations (parkinsonism, dystonia) while emphasizing limited genotype–phenotype correlation. Publication date: May 2023; URL: https://doi.org/10.1186/s12920-023-01529-4. (celik2023anovelmutation pages 1-2)
  2. 2023 BMJ Case Reports: A 2023 BMJ Case Reports paper highlights clinical utility of recognizing hypogonadism to narrow ataxia differentials and links GHS to RNF216/OTUD4 ubiquitin-proteasome biology. Publication date: Nov 2023; URL: https://doi.org/10.1136/bcr-2023-256994. (kallupurakkal2023anovelmutation pages 1-2)
  3. 2024 endocrine-first RNF216: A 2024 JCEM Case Reports article stresses that HH may be the first manifestation, particularly in males, supporting earlier genetic evaluation in delayed puberty with suggestive imaging/neuro signs. Publication date: Oct 2024; URL: https://doi.org/10.1210/jcemcr/luae195. (rochtus2024hypogonadotropichypogonadismas pages 1-2)
  4. 2024 mechanistic mouse work: A 2024 eNeuro paper provides new mechanistic data implicating microglia/neuroinflammation and sex-specific neuroendocrine differences in Rnf216 deficiency. Publication date: Dec 2024; URL: https://doi.org/10.1523/eneuro.0074-23.2023. (george2024gordonholmessyndrome pages 1-2, george2024gordonholmessyndrome pages 16-17)
  5. 2024 PNPLA6 case reports: A 2024 Molecular Biology Reports paper reiterates lack of disease-modifying treatment and provides explicit management recommendations for BNS. Publication date: Apr 2024; URL: https://doi.org/10.1007/s11033-024-09515-4. (liampas2024twocasereports pages 5-8)

Current applications and real-world implementations (registries/clinical research)

A broad rare-disease registry and natural history platform CoRDS (Coordination of Rare Diseases at Sanford; NCT01793168) is recruiting and includes rare hereditary ataxias among its condition list, providing an infrastructure for patient–researcher connection and longitudinal data collection (ClinicalTrials.gov first posted 2013-02-15; last update posted 2025-05-29). (NCT01793168 chunk 2, NCT01793168 chunk 3)

Visual evidence from primary literature

Shi et al. (Human Molecular Genetics, 2014) provides a consolidated table and MRI/hormone stimulation figure for STUB1/CHIP-related GHS: - Table with clinical scores and reproductive hormones/ultrasound findings (Table 1). (shi2014ataxiaandhypogonadism media 319d7677) - MRI evidence of cerebellar atrophy and GnRH stimulation response curves (Figure 1). (shi2014ataxiaandhypogonadism media 6ceea760) - Genetic analysis/pedigree identifying homozygous STUB1 p.Thr246Met and recessive inheritance (Figure 2). (shi2014ataxiaandhypogonadism media 8fe7f28b)

Summary tables

Gene Syndrome label(s) in sources Inheritance noted Example variants (HGVS) reported in evidence Core molecular function/pathway Key clinical features/imaging from evidence Key sources with year and DOI URL
RNF216 Gordon Holmes syndrome (GHS); RNF216-related disorder; also reported with Huntington-like disease, 4H syndrome, congenital hypogonadotropic hypogonadism Usually autosomal recessive/monogenic biallelic; oligogenic/digenic cases also reported with OTUD4 and SRA1 c.1860_1861dupCT (p.Cys621SerfsTer56); c.2061G>A (splice); c.1549C>T (p.R517X); c.591_592insTG (p.Gln198CysfsTer43); c.2042C>T (p.P606L) RBR-class E3 ubiquitin ligase; ubiquitin-proteasome/autophagy pathway; E3 activity depends on RBR domain + C-terminal extension Core phenotype: hypogonadotropic hypogonadism, cerebellar ataxia, cognitive decline/dementia, chorea/other movement disorders; MRI: cerebellar and cortical atrophy, cerebral white-matter hyperintensities/leukoencephalopathy, thin posterior corpus callosum; some pituitary anomalies (hypoplastic posterior pituitary, partial empty sella) (rochtus2024hypogonadotropichypogonadismas pages 1-2, alqwaifly2016ataxiaandhypogonadotropic pages 1-2, calandra2019gordonholmessyndrome pages 1-4, wu2022gordonholmessyndrome pages 7-11, wu2022gordonholmessyndrome pages 1-4, kallupurakkal2023anovelmutation pages 1-2, celik2023anovelmutation pages 1-2) Rochtus 2024, https://doi.org/10.1210/jcemcr/luae195; Çelik 2023, https://doi.org/10.1186/s12920-023-01529-4; Kallupurakkal 2023, https://doi.org/10.1136/bcr-2023-256994; Alqwaifly 2016, https://doi.org/10.4081/ni.2016.6444; Calandra 2019, https://doi.org/10.1002/mdc3.12721; Wu 2022, https://doi.org/10.21203/rs.3.rs-1310364/v1
OTUD4 GHS; RNF216/OTUD4 digenic form Digenic/oligogenic with RNF216 reported Not specified in provided snippets Deubiquitinase; disordered ubiquitination pathway Included in GHS spectrum with ataxia, hypogonadotropic hypogonadism, dementia/cognitive decline; more severe phenotypes reported when combined with RNF216 dysfunction in source summaries (margolin2013ataxiadementiaand pages 9-11, alqwaifly2016ataxiaandhypogonadotropic pages 1-2, calandra2019gordonholmessyndrome pages 1-4, wu2022gordonholmessyndrome pages 7-11, george2024gordonholmessyndrome pages 16-17) Margolin 2013, https://doi.org/10.1056/NEJMoa1215993; Alqwaifly 2016, https://doi.org/10.4081/ni.2016.6444; Wu 2022, https://doi.org/10.21203/rs.3.rs-1310364/v1
STUB1 (CHIP) GHS; SCAR16/STUB1-related multisystemic neurodegeneration Autosomal recessive/biallelic in reported GHS cases c.737C>T (p.Thr246Met); c.194A>G (p.Asn65Ser); c.82G>A (p.Glu28Lys); c.430A>T (p.Lys144Ter) Co-chaperone/E3 ubiquitin ligase in protein quality control/homeostasis Cerebellar ataxia with hypogonadotropic hypogonadism; dysarthria, gaze-evoked nystagmus, severe dementia/cognitive impairment in some families; MRI: remarkable cerebellar atrophy; pituitary responsive to GnRH in reported sisters; broader multisystemic features can include spastic tetraparesis, epilepsy, autonomic dysfunction (shi2014ataxiaandhypogonadism pages 1-2, shi2014ataxiaandhypogonadism media 319d7677, shi2014ataxiaandhypogonadism media 6ceea760, shi2014ataxiaandhypogonadism media 8fe7f28b) Shi 2014, https://doi.org/10.1093/hmg/ddt497; Hayer 2017, https://doi.org/10.1186/s13023-017-0580-x; Heimdal 2014, https://doi.org/10.1186/s13023-014-0146-0
PNPLA6 Gordon Holmes syndrome (GH/GDHS); Boucher-Neuhauser syndrome (BNHS/BNS); also broader PNPLA6-related spectrum (SPG39, Oliver-McFarlane, Laurence-Moon) Autosomal recessive/biallelic; often sibling cases; consanguinity common in several reports c.3524C>G (p.Ser1175Cys); c.3323G>A (p.Arg1108Gln); c.3380C>G (p.Ser1127Cys); c.3847G>A (p.V1283M); c.3929A>T (p.D1310V) Neuropathy target esterase (NTE); ER-localized lysophospholipase/phospholipase esterase GHS/BNHS spectrum with cerebellar ataxia, hypogonadotropic hypogonadism, chorioretinal dystrophy/vision loss; additional features include peripheral axonal neuropathy, spasticity, growth hormone deficiency, cognitive impairment, vestibular areflexia; MRI often shows cerebellar atrophy, especially superior/dorsal vermis; progression may be slow with retained ambulation after long disease duration in some cohorts (nanetti2022multifacetedandagedependent pages 1-2, dogan2021chorioretinaldystrophyhypogonadotropic pages 1-3, nanetti2022multifacetedandagedependent pages 3-5, liampas2024twocasereports pages 5-8, liampas2024twocasereports pages 1-5, deik2014compoundheterozygouspnpla6 pages 1-2, canbek2024…>g pages 2-4, teive2018differentcerebellarataxia pages 5-6) Nanetti 2022, https://doi.org/10.3389/fneur.2021.793547; Doğan 2021, https://doi.org/10.1080/13816810.2021.1894461; Liampas 2024, https://doi.org/10.1007/s11033-024-09515-4; Deik 2014, https://doi.org/10.1007/s00415-014-7516-3; Teive 2018, https://doi.org/10.1007/s12311-017-0909-y
POLR3A / POLR3B / POLR1C 4H syndrome listed among ataxia-hypogonadism differential/overlap disorders Not specified in provided snippets Not specified in provided snippets RNA polymerase III pathway (specific function not detailed in snippets) Mentioned as genes associated with ataxia plus hypogonadism spectrum/4H overlap; no variant-level or imaging detail provided in the retrieved evidence snippets (calandra2019gordonholmessyndrome pages 1-4, wu2022gordonholmessyndrome pages 7-11, kallupurakkal2023anovelmutation pages 1-2, celik2023anovelmutation pages 1-2) Calandra 2019, https://doi.org/10.1002/mdc3.12721; Wu 2022, https://doi.org/10.21203/rs.3.rs-1310364/v1; Kallupurakkal 2023, https://doi.org/10.1136/bcr-2023-256994

Table: This table summarizes the principal genes implicated across the cerebellar ataxia–hypogonadism / Gordon Holmes syndrome spectrum, including inheritance models, representative variants, molecular functions, and phenotype/imaging findings supported by the retrieved evidence.

Key evidence-backed abstract quotes (verbatim)

  • “Gordon Holmes syndrome (GHS) is a rare Mendelian neurodegenerative disorder characterized by ataxia and hypogonadism.” (Shi et al., 2014; https://doi.org/10.1093/hmg/ddt497) (shi2014ataxiaandhypogonadism pages 1-2)

Evidence gaps / limitations

  • Curated identifiers beyond MIM/OMIM (MONDO, Orphanet, MeSH, ICD-10/11) were not present in the retrieved evidence for this run; population prevalence/incidence and standardized diagnostic criteria were also not identified.
  • Many “Cerebellar ataxia–hypogonadism” cases are genetically heterogeneous; phenotype frequencies depend strongly on the causal gene (e.g., RNF216 vs PNPLA6), so frequency statements are reported only where explicitly quantified in the cited sources (not generalized across the entire syndrome label). (nanetti2022multifacetedandagedependent pages 1-2, rochtus2024hypogonadotropichypogonadismas pages 1-2)

References

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  3. (george2024gordonholmessyndrome pages 1-2): Arlene J. George, Wei Wei, Dhanya N. Pyaram, Morgan Gomez, Nitheyaa Shree, Jayashree Kadirvelu, Hannah Lail, Desiree Wanders, Anne Z. Murphy, and Angela M. Mabb. Gordon holmes syndrome model mice exhibit alterations in microglia, age, and sex-specific disruptions in cognitive and proprioceptive function. eNeuro, 11:ENEURO.0074-23.2023, Dec 2024. URL: https://doi.org/10.1523/eneuro.0074-23.2023, doi:10.1523/eneuro.0074-23.2023. This article has 0 citations and is from a peer-reviewed journal.

  4. (nanetti2022multifacetedandagedependent pages 1-2): Lorenzo Nanetti, Daniela Di Bella, Stefania Magri, Mario Fichera, Elisa Sarto, Anna Castaldo, Alessia Mongelli, Silvia Baratta, Silvia Fenu, Marco Moscatelli, Maria Teresa Bonati, Andrea Martinuzzi, Caterina Mariotti, and Franco Taroni. Multifaceted and age-dependent phenotypes associated with biallelic pnpla6 gene variants: eight novel cases and review of the literature. Frontiers in Neurology, Jan 2022. URL: https://doi.org/10.3389/fneur.2021.793547, doi:10.3389/fneur.2021.793547. This article has 18 citations and is from a peer-reviewed journal.

  5. (liampas2024twocasereports pages 5-8): Andreas Liampas, Paschalis Nicolaou, Christina Votsi, Anthi Georghiou, Kyproula Christodoulou, George A Tanteles, and Marios Pantzaris. Two case reports of a novel missense mutation in the pnpla6 gene in two siblings with chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia. Molecular biology reports, 51 1:590, Apr 2024. URL: https://doi.org/10.1007/s11033-024-09515-4, doi:10.1007/s11033-024-09515-4. This article has 0 citations and is from a peer-reviewed journal.

  6. (deik2014compoundheterozygouspnpla6 pages 1-2): A. Deik, Brooke Johannes, J. Rucker, E. Sánchez, S. Brodie, E. Deegan, K. Landy, Y. Kajiwara, S. Scelsa, R. Saunders-Pullman, R. Saunders-Pullman, and C. Paisán-Ruiz. Compound heterozygous pnpla6 mutations cause boucher–neuhäuser syndrome with late-onset ataxia. Journal of Neurology, 261:2411-2423, Sep 2014. URL: https://doi.org/10.1007/s00415-014-7516-3, doi:10.1007/s00415-014-7516-3. This article has 44 citations and is from a domain leading peer-reviewed journal.

  7. (wu2022gordonholmessyndrome pages 7-11): Chujun Wu and Zaiqiang Zhang. Gordon holmes syndrome and huntington-like disease: two types of rnf216-related disorders. ArXiv, Feb 2022. URL: https://doi.org/10.21203/rs.3.rs-1310364/v1, doi:10.21203/rs.3.rs-1310364/v1. This article has 1 citations.

  8. (calandra2019gordonholmessyndrome pages 1-4): Cristian R. Calandra, Yamile Mocarbel, Sebastian A. Vishnopolska, Vanessa Toneguzzo, Jaen Oliveri, Enrique Carlos Cazado, German Biagioli, Adrián G. Turjanksi, and Marcelo Marti. Gordon holmes syndrome caused by rnf216 novel mutation in 2 argentinean siblings. Movement Disorders Clinical Practice, 6:259-262, Mar 2019. URL: https://doi.org/10.1002/mdc3.12721, doi:10.1002/mdc3.12721. This article has 26 citations and is from a peer-reviewed journal.

  9. (kallupurakkal2023anovelmutation pages 1-2): Arjun Bal Kallupurakkal, Rajesh Verma, and Rajarshi Chakraborty. A novel mutation in rnf216 gene in an indian case with gordon holmes syndrome. BMJ Case Reports, 16:e256994, Nov 2023. URL: https://doi.org/10.1136/bcr-2023-256994, doi:10.1136/bcr-2023-256994. This article has 6 citations and is from a peer-reviewed journal.

  10. (alqwaifly2016ataxiaandhypogonadotropic pages 1-2): Mohammed Alqwaifly and Saeed Bohlega. Ataxia and hypogonadotropic hypogonadism with intrafamilial variability caused by rnf216 mutation. Neurology International, Jun 2016. URL: https://doi.org/10.4081/ni.2016.6444, doi:10.4081/ni.2016.6444. This article has 46 citations.

  11. (margolin2013ataxiadementiaand pages 9-11): David H. Margolin, Maria Kousi, Yee-Ming Chan, Elaine T. Lim, Jeremy D. Schmahmann, Marios Hadjivassiliou, Janet E. Hall, Ibrahim Adam, Andrew Dwyer, Lacey Plummer, Stephanie V. Aldrin, Julia O'Rourke, Andrew Kirby, Kasper Lage, Aubrey Milunsky, Jeff M. Milunsky, Jennifer Chan, E. Tessa Hedley-Whyte, Mark J. Daly, Nicholas Katsanis, and Stephanie B. Seminara. Ataxia, dementia, and hypogonadotropism caused by disordered ubiquitination. New England Journal of Medicine, 368:1992-2003, May 2013. URL: https://doi.org/10.1056/nejmoa1215993, doi:10.1056/nejmoa1215993. This article has 268 citations and is from a highest quality peer-reviewed journal.

  12. (celik2023anovelmutation pages 1-2): Nazlı Durmaz Çelik, Ebru Erzurumluoğlu, Serkan Özben, Uğur Toprak, Göknur Yorulmaz, Sevilhan Artan, and Serhat Özkan. A novel mutation in rnf216 gene in a turkish case with gordon holmes syndrome. BMC Medical Genomics, May 2023. URL: https://doi.org/10.1186/s12920-023-01529-4, doi:10.1186/s12920-023-01529-4. This article has 9 citations and is from a peer-reviewed journal.

  13. (wu2022gordonholmessyndrome pages 1-4): Chujun Wu and Zaiqiang Zhang. Gordon holmes syndrome and huntington-like disease: two types of rnf216-related disorders. ArXiv, Feb 2022. URL: https://doi.org/10.21203/rs.3.rs-1310364/v1, doi:10.21203/rs.3.rs-1310364/v1. This article has 1 citations.

  14. (canbek2024…>g pages 2-4): S Canbek and MG Şenol. … > g missense mutation in pnpla6 gene in a case of gordon holmes syndrome associated with hypogonadotropic hypogonadism, cerebellar ataxia, and juvenile type …. Unknown journal, 2024.

  15. (george2024gordonholmessyndrome pages 16-17): Arlene J. George, Wei Wei, Dhanya N. Pyaram, Morgan Gomez, Nitheyaa Shree, Jayashree Kadirvelu, Hannah Lail, Desiree Wanders, Anne Z. Murphy, and Angela M. Mabb. Gordon holmes syndrome model mice exhibit alterations in microglia, age, and sex-specific disruptions in cognitive and proprioceptive function. eNeuro, 11:ENEURO.0074-23.2023, Dec 2024. URL: https://doi.org/10.1523/eneuro.0074-23.2023, doi:10.1523/eneuro.0074-23.2023. This article has 0 citations and is from a peer-reviewed journal.

  16. (dogan2021chorioretinaldystrophyhypogonadotropic pages 1-3): Mustafa Doğan, Recep Eröz, and Emrah Öztürk. Chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia: boucher-neuhauser syndrome due to a homozygous (c.3524c>g (p.ser1175cys)) variant in pnpla6 gene. Ophthalmic Genetics, 42:276-282, Mar 2021. URL: https://doi.org/10.1080/13816810.2021.1894461, doi:10.1080/13816810.2021.1894461. This article has 12 citations and is from a peer-reviewed journal.

  17. (liampas2024twocasereports pages 1-5): Andreas Liampas, Paschalis Nicolaou, Christina Votsi, Anthi Georghiou, Kyproula Christodoulou, George A Tanteles, and Marios Pantzaris. Two case reports of a novel missense mutation in the pnpla6 gene in two siblings with chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar ataxia. Molecular biology reports, 51 1:590, Apr 2024. URL: https://doi.org/10.1007/s11033-024-09515-4, doi:10.1007/s11033-024-09515-4. This article has 0 citations and is from a peer-reviewed journal.

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  19. (shi2014ataxiaandhypogonadism media 6ceea760): Chang-He Shi, Jonathan C. Schisler, Carrie E. Rubel, Song Tan, Bo Song, Holly McDonough, Lei Xu, Andrea L. Portbury, Cheng-Yuan Mao, Cadence True, Rui-Hao Wang, Qing-Zhi Wang, Shi-Lei Sun, Stephanie B. Seminara, Cam Patterson, and Yu-Ming Xu. Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the u box protein chip. Human molecular genetics, 23 4:1013-24, Feb 2014. URL: https://doi.org/10.1093/hmg/ddt497, doi:10.1093/hmg/ddt497. This article has 153 citations and is from a domain leading peer-reviewed journal.

  20. (NCT01793168 chunk 2): Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford. Sanford Health. 2010. ClinicalTrials.gov Identifier: NCT01793168

  21. (NCT01793168 chunk 3): Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford. Sanford Health. 2010. ClinicalTrials.gov Identifier: NCT01793168

  22. (shi2014ataxiaandhypogonadism media 319d7677): Chang-He Shi, Jonathan C. Schisler, Carrie E. Rubel, Song Tan, Bo Song, Holly McDonough, Lei Xu, Andrea L. Portbury, Cheng-Yuan Mao, Cadence True, Rui-Hao Wang, Qing-Zhi Wang, Shi-Lei Sun, Stephanie B. Seminara, Cam Patterson, and Yu-Ming Xu. Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the u box protein chip. Human molecular genetics, 23 4:1013-24, Feb 2014. URL: https://doi.org/10.1093/hmg/ddt497, doi:10.1093/hmg/ddt497. This article has 153 citations and is from a domain leading peer-reviewed journal.

  23. (shi2014ataxiaandhypogonadism media 8fe7f28b): Chang-He Shi, Jonathan C. Schisler, Carrie E. Rubel, Song Tan, Bo Song, Holly McDonough, Lei Xu, Andrea L. Portbury, Cheng-Yuan Mao, Cadence True, Rui-Hao Wang, Qing-Zhi Wang, Shi-Lei Sun, Stephanie B. Seminara, Cam Patterson, and Yu-Ming Xu. Ataxia and hypogonadism caused by the loss of ubiquitin ligase activity of the u box protein chip. Human molecular genetics, 23 4:1013-24, Feb 2014. URL: https://doi.org/10.1093/hmg/ddt497, doi:10.1093/hmg/ddt497. This article has 153 citations and is from a domain leading peer-reviewed journal.

  24. (nanetti2022multifacetedandagedependent pages 3-5): Lorenzo Nanetti, Daniela Di Bella, Stefania Magri, Mario Fichera, Elisa Sarto, Anna Castaldo, Alessia Mongelli, Silvia Baratta, Silvia Fenu, Marco Moscatelli, Maria Teresa Bonati, Andrea Martinuzzi, Caterina Mariotti, and Franco Taroni. Multifaceted and age-dependent phenotypes associated with biallelic pnpla6 gene variants: eight novel cases and review of the literature. Frontiers in Neurology, Jan 2022. URL: https://doi.org/10.3389/fneur.2021.793547, doi:10.3389/fneur.2021.793547. This article has 18 citations and is from a peer-reviewed journal.

  25. (teive2018differentcerebellarataxia pages 5-6): Hélio Afonso Ghizoni Teive, Carlos Henrique F. Camargo, Mario Teruo Sato, Naoye Shiokawa, Cesar L. Boguszewski, Salmo Raskin, Cassandra Buck, Stephanie B. Seminara, and Renato Puppi Munhoz. Different cerebellar ataxia phenotypes associated with mutations of the pnpla6 gene in brazilian patients with recessive ataxias. The Cerebellum, 17:380-385, Dec 2018. URL: https://doi.org/10.1007/s12311-017-0909-y, doi:10.1007/s12311-017-0909-y. This article has 35 citations.

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