X-linked intellectual disability-limb spasticity-retinal dystrophy-diabetes insipidus syndrome

Summary

X-linked intellectual disability-limb spasticity-retinal dystrophy-diabetes insipidus syndrome (MONDO:0018495) is a disease with 1 cohort gene.

At a glance

• Prevalence: <1 / 1 000 000 (Worldwide) [Orphanet-validated]
• Cohort genes: 1
• Phenotypes (HPO): 35

Clinical features

Epidemiology

Prevalence records

2 prevalence record(s), Orphanet:

Type	Class	Value	Geography	Validation
Cases/families		2	Worldwide	Validated
Point prevalence	<1 / 1 000 000		Worldwide	Validated

Signs & symptoms

Clinical features (HPO)

35 HPO clinical features (Orphanet curated; top 35 by frequency):

HPO ID	Term	Frequency
HP:0002187	Intellectual disability, profound	Very frequent (80-99%)
HP:0008058	Aplasia/Hypoplasia of the optic nerve	Frequent (30-79%)
HP:0008936	Axial hypotonia	Frequent (30-79%)
HP:0011471	Gastrostomy tube feeding in infancy	Frequent (30-79%)
HP:0012448	Delayed myelination	Frequent (30-79%)
HP:0012736	Profound global developmental delay	Frequent (30-79%)
HP:0030211	Slow pupillary light response	Frequent (30-79%)
HP:0000268	Dolichocephaly	Frequent (30-79%)
HP:0000316	Hypertelorism	Frequent (30-79%)
HP:0000369	Low-set ears	Frequent (30-79%)
HP:0000407	Sensorineural hearing impairment	Frequent (30-79%)
HP:0000430	Underdeveloped nasal alae	Frequent (30-79%)
HP:0000490	Deeply set eye	Frequent (30-79%)
HP:0000543	Optic disc pallor	Frequent (30-79%)
HP:0000556	Retinal dystrophy	Frequent (30-79%)
HP:0000577	Exotropia	Frequent (30-79%)
HP:0000873	Diabetes insipidus	Frequent (30-79%)
HP:0001116	Macular coloboma	Frequent (30-79%)
HP:0001285	Spastic tetraparesis	Frequent (30-79%)
HP:0001511	Intrauterine growth retardation	Frequent (30-79%)
HP:0001525	Severe failure to thrive	Frequent (30-79%)
HP:0002069	Bilateral tonic-clonic seizure	Frequent (30-79%)
HP:0002079	Hypoplasia of the corpus callosum	Frequent (30-79%)
HP:0002509	Limb hypertonia	Frequent (30-79%)
HP:0004322	Short stature	Frequent (30-79%)
HP:0004639	Elevated amniotic fluid alpha-fetoprotein	Frequent (30-79%)
HP:0006801	Hyperactive deep tendon reflexes	Frequent (30-79%)
HP:0007965	Undetectable visual evoked potentials	Frequent (30-79%)
HP:0002169	Clonus	Occasional (5-29%)
HP:0003487	Babinski sign	Occasional (5-29%)
HP:0006579	Prolonged neonatal jaundice	Occasional (5-29%)
HP:0010536	Central sleep apnea	Occasional (5-29%)
HP:0030921	5-minute APGAR score of 1	Occasional (5-29%)
HP:0030927	1-minute APGAR score of 0	Occasional (5-29%)
HP:0011903	HbH hemoglobin	Excluded (0%)

Identifiers

Disease identifiers

Field	Value
Canonical name	X-linked intellectual disability-limb spasticity-retinal dystrophy-diabetes insipidus syndrome
Mondo ID	MONDO:0018495
Orphanet	423479
UMLS	C4517296
MedGen	1374000
GARD	0021752
Is cancer (heuristic)	no

Data availability: 1 GenCC gene-disease record.

Disease family

Classification path: disease › human disease › disease by body system or component › nervous system disorder › retinal disorder › retinal degeneration › inherited retinal dystrophy › X-linked intellectual disability-limb spasticity-retinal dystrophy-diabetes insipidus syndrome

Related subtypes (104): retinal dystrophies primarily involving Bruch’s membrane, vitreoretinal dystrophy, dystrophies primarily involving the retinal pigment epithelium, retinal dystrophy in systemic or cerebroretinal lipidoses, age-related macular degeneration, helicoid peripapillary chorioretinal degeneration, Sorsby fundus dystrophy, microcephaly with or without chorioretinopathy, lymphedema, or intellectual disability, pigmented paravenous retinochoroidal atrophy, retinoschisis, autosomal dominant, retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations, amaurosis-hypertrichosis syndrome, familial benign flecked retina, microcephaly and chorioretinopathy 1, ornithine aminotransferase deficiency, retinal degeneration-nanophthalmos-glaucoma syndrome, retinoschisis of fovea, Revesz syndrome, choroideremia, choroideremia-deafness-obesity syndrome, X-linked retinal dysplasia, X-linked retinoschisis, progressive bifocal chorioretinal atrophy, aceruloplasminemia, late-onset retinal degeneration, infantile cerebellar-retinal degeneration, progressive retinal dystrophy due to retinol transport defect, microcornea-myopic chorioretinal atrophy, retinal dystrophy with inner retinal dysfunction and ganglion cell anomalies, macular degeneration, early-onset, cone-rod dystrophy, ectopia lentis-chorioretinal dystrophy-myopia syndrome, foveal hypoplasia-presenile cataract syndrome, MRCS syndrome, Leber congenital amaurosis, oligocone trichromacy, Oguchi disease, retinitis pigmentosa, hereditary macular dystrophy, RPE65-related recessive retinopathy, RPGR-related retinopathy, AIPL1-related retinopathy, RP2-related retinopathy, RDH5-related retinopathy, RLBP1-related retinopathy, LCA5-related retinopathy, ATF6-related retinopathy, RAB28-related retinopathy, FLVCR1-related retinopathy with or without ataxia, RPE65-related dominant retinopathy, GUCY2D retinopathy, PDE6A-related retinopathy, ELOVL4-related maculopathy, MAK-related retinopathy, KIZ-related retinopathy, TOPORS-related retinopathy, PRPF8-related retinopathy, RD3-related retinopathy, BEST1-related dominant retinopathy, BEST1-related recessive retinopathy, IMPG2-related recessive retinopathy, IMPG2-related dominant retinopathy, CACNA1F-related retinopathy, CACNA2D4-related retinopathy, CDHR1-related retinopathy, GUCA1A-related retinopathy, RHO-related retinopathy, SNRNP200-related dominant retinopathy, RDH12-related recessive retinopathy, RDH12-related dominant retinopathy, NMNAT1-related retinopathy, CNGA3-related retinopathy, EYS-related retinopathy, GNAT2-related retinopathy, IDH3B-related retinopathy, MERTK-related retinopathy, PRPF31-related retinopathy, GPR179-related retinopathy, GRM6-related retinopathy, ADAM9-related retinopathy, RP1-related recessive retinopathy, RP1-related dominant retinopathy, CERKL-related retinopathy, TRPM1-related retinopathy, CNGB1-related retinopathy, PCARE-related retinopathy, CNGA1-related retinopathy, ABCA4-related retinopathy, NYX-related retinopathy, retinal dystrophy, X-linked, Gardner-Hardcastle type, PDE6C-related retinopathy, PDE6G-related retinopathy, LRIT3-related retinopathy, IMPG1-related dominant retinopathy, IMPG1-related recessive retinopathy, TTLL5-related retinopathy, HGSNAT-related retinopathy, IMPDH1-related retinopathy, PRPH2-related retinopathy, PROM1-related retinopathy, KCNV2-related retinopathy, CRX-related retinopathy, REEP6-related retinopathy, SPATA7-related retinopathy

Genetics & variants

GWAS landscape

No GWAS associations recorded — common-variant (GWAS) studies don’t cover this disease (typical for Mendelian / rare diseases). See the curated gene cohort and Mendelian overlap below.

Variant details and genetic-evidence tiers

No tiered GWAS variants or ClinVar records for this disease.

Genes & proteins

Mendelian disease overlap and somatic drivers

GenCC: 17 · Orphanet: 6 · OMIM-shared: 0 · Dual-evidence (GWAS+Mendelian): 0

GenCC gene–disease validity (cohort genes)

the Disease column is the GenCC-asserted condition — a cohort gene’s strongest validity may be for a related predisposition syndrome.

Gene	Classification	Inheritance	Disease	Records
PRPS1	Definitive	X-linked	hearing loss, X-linked 1	17

Orphanet rare-disease linkage (cohort genes)

Gene	Orphanet ID	Rare disease
PRPS1	Orphanet:1187	Lethal ataxia with deafness and optic atrophy
PRPS1	Orphanet:411536	Mild phosphoribosylpyrophosphate synthetase superactivity
PRPS1	Orphanet:411543	Severe phosphoribosylpyrophosphate synthetase superactivity
PRPS1	Orphanet:423479	X-linked intellectual disability-limb spasticity-retinal dystrophy-arginine vasopressin deficiency
PRPS1	Orphanet:90625	Rare X-linked non-syndromic sensorineural deafness type DFN
PRPS1	Orphanet:99014	X-linked Charcot-Marie-Tooth disease type 5

Cohort genes → proteins

1 cohort genes, 1 distinct canonical proteins.

Evidence partition

Subset	Genes
multi_evidence	1

Cohort genes (full)

Symbol	HGNC	Ensembl	UniProt	Name	Evidence
PRPS1	HGNC:9462	ENSG00000147224	P60891	Ribose-phosphate pyrophosphokinase 1	gencc

Cohort function summary

Lead sentence per gene, UniProt-curated.

Symbol	Protein name	Function (lead sentence)
PRPS1	Ribose-phosphate pyrophosphokinase 1	Catalyzes the synthesis of phosphoribosylpyrophosphate (PRPP) that is essential for nucleotide synthesis.

Protein-family classification

Druggable: 1 · Difficult: 0 · Unknown: 0 · Druggable fraction: 1.0

Family distribution

Cohort families vs a genome-wide background (hypergeometric, BH-FDR; fold = observed/expected). Counts kept; sorted by enrichment, so the catch-all Other/Unknown bucket no longer leads.

Family	Genes	Fold	FDR
Kinase	1	27.7×	0.036

Per-gene assignment

Symbol	Family	Druggable?	EC	InterPro (top 3)
PRPS1	Kinase	yes	2.7.6.1	PRTase_dom, PRib_PP_synth_CS, Rib-P_diPkinase

Expression context

Cohort genes with no expression data: 0.

1 cohort gene are a single-cell marker in ≥1 SCXA experiment.

Breadth distribution (Bgee present_calls)

Bucket	Genes
narrow (1-5 tissues)	0
moderate (6-20)	0
broad (>20)	1
unknown	0

Top tissues across cohort

Tissue	Cohort genes
islet of Langerhans	1
sural nerve	1
ventricular zone	1

Per-gene tissue summary (top 30)

Symbol	Bgee breadth	FANTOM5 breadth	SCXA	Top tissues
PRPS1	291	ubiquitous	marker	islet of Langerhans, ventricular zone, sural nerve

Protein interactions among cohort

Intra-cohort edges: 0.

Hub genes (top 10 by interactor count)

Symbol	Interactor count
PRPS1	881

Structural data

PDB: 1 · AlphaFold-only: 0 · No structure: 0

Cohort genes with PDB structures (top 30)

Symbol	UniProt	PDB entries
PRPS1	P60891	27

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 1. Enrichment computed across 1 evidence-associated genes (1 with Reactome annotation).

Pathways by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

Pathway	Cohort genes	Fold	FDR	Sample cohort genes
5-Phosphoribose 1-diphosphate biosynthesis	1	3806.7×	3e-04	PRPS1

GO biological processes by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

GO term	Cohort genes	Fold	FDR	Sample cohort genes
hypoxanthine biosynthetic process	1	16852.0×	3e-04	PRPS1
pyrimidine nucleotide biosynthetic process	1	8426.0×	3e-04	PRPS1
urate biosynthetic process	1	8426.0×	3e-04	PRPS1
ribonucleoside monophosphate biosynthetic process	1	4213.0×	5e-04	PRPS1
5-phosphoribose 1-diphosphate biosynthetic process	1	3370.4×	5e-04	PRPS1
purine nucleobase metabolic process	1	2407.4×	6e-04	PRPS1
purine nucleotide biosynthetic process	1	1296.3×	9e-04	PRPS1
nervous system development	1	45.9×	0.022	PRPS1

Therapeutics

Drug target analysis

Approved (phase 4): 0 · Phase ≥3: 0 · Phased (≥1): 0 · Undrugged: 1

Druggability breadth: 1 of 1 evidence-associated genes (100%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Top cohort targets by molecule count

Symbol	Molecules	Max phase
PRPS1	0	0

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 1.

Cohort genes with ChEMBL bioactivity (full, sorted by assay count)

Symbol	Assays	Type breakdown
PRPS1	10	Binding:10

Cohort enzymes (BRENDA EC)

Symbol	EC numbers	Names
PRPS1	2.7.6.1	ribose-phosphate diphosphokinase

Pharmacogenomics

Cohort genes with a PharmGKB record: 1; with CPIC/DPWG dosing guidelines: 0.

No cohort gene has a CPIC/DPWG genotype-guided dosing guideline (PharmGKB).

Chemical tractability of cohort targets

0 approved/phased compounds have measured bioactivity against a cohort gene (and aren’t yet in disease-level trials). This is a research / tractability signal, NOT a therapeutic recommendation — a bioactivity row often reflects off-target or screening binding (e.g. promiscuous kinase inhibitors against a cohort kinase), implying no disease mechanism.

Druggability pyramid

Cohort genes binned by druggability tier (high → low):

Tier	Definition	Genes	Symbols
A	Approved (phase 4 drug)	0
B	Phased (≥1) drug, not yet approved	0
C	Druggable family + PDB, no drug	1	PRPS1
D	Druggable family + AlphaFold only, no drug	0
E	Difficult family or no structure, no drug	0

Undrugged target profiles

1 cohort genes are undrugged. Ranked by ‘starting-point quality’ (assay depth + drugged-partner adjacency).

Symbol	ChEMBL assays	Drugged partners (top 3)
PRPS1	10	—

Clinical trials & evidence

Clinical trials

Clinical trials: 0.