Spinocerebellar ataxia type 18

disease

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Also known as SCA18sensorimotor neuropathy with ataxia autosomal dominantSMNAspinocerebellar ataxia 18

Summary

Spinocerebellar ataxia type 18 (MONDO:0011834) is a disease with 1 cohort gene and 1 clinical trial.

At a glance

Prevalence: <1 / 1 000 000 (Worldwide) [Orphanet-validated]
Cohort genes: 1
Phenotypes (HPO): 18
Clinical trials: 1

Clinical features

Epidemiology

Prevalence records

2 prevalence record(s), Orphanet:

Type	Class	Value	Geography	Validation
Cases/families		26	Worldwide	Validated
Point prevalence	<1 / 1 000 000		Worldwide	Validated

Signs & symptoms

Clinical features (HPO)

18 HPO clinical features (Orphanet curated; top 18 by frequency):

HPO ID	Term	Frequency
HP:0001284	Areflexia	Very frequent (80-99%)
HP:0001324	Muscle weakness	Very frequent (80-99%)
HP:0002066	Gait ataxia	Very frequent (80-99%)
HP:0003474	Somatic sensory dysfunction	Very frequent (80-99%)
HP:0000365	Hearing impairment	Frequent (30-79%)
HP:0001260	Dysarthria	Frequent (30-79%)
HP:0001310	Dysmetria	Frequent (30-79%)
HP:0001761	Pes cavus	Frequent (30-79%)
HP:0002395	Lower limb hyperreflexia	Frequent (30-79%)
HP:0002600	Hyporeflexia of lower limbs	Frequent (30-79%)
HP:0007141	Sensorimotor neuropathy	Frequent (30-79%)
HP:0010546	Muscle fibrillation	Frequent (30-79%)
HP:0000639	Nystagmus	Occasional (5-29%)
HP:0001272	Cerebellar atrophy	Occasional (5-29%)
HP:0002346	Head tremor	Occasional (5-29%)
HP:0003202	Skeletal muscle atrophy	Occasional (5-29%)
HP:0003477	Peripheral axonal neuropathy	Occasional (5-29%)
HP:0030187	Titubation	Occasional (5-29%)

Identifiers

Disease identifiers

Field	Value
Canonical name	spinocerebellar ataxia type 18
Mondo ID	MONDO:0011834
MeSH	C537197
OMIM	607458
Orphanet	98771
DOID	DOID:0050969
ICD-11	1564628854
SNOMED CT	719250005
UMLS	C1843884
MedGen	336066
GARD	0009976
Is cancer (heuristic)	no

Also known as: SCA18 · sensorimotor neuropathy with ataxia autosomal dominant · SMNA · spinocerebellar ataxia 18

Data availability: 1 GenCC gene-disease record.

Disease family

Classification path: disease › human disease › disease by etiologic mechanism › disease of genetic or genomic mechanism › hereditary disease › autosomal genetic disease › autosomal dominant disease › autosomal dominant cerebellar ataxia › autosomal dominant cerebellar ataxia type I › spinocerebellar ataxia type 18

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: 2 · Orphanet: 1 · 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
IFRD1	Supportive	Autosomal dominant	spinocerebellar ataxia type 18	2

Orphanet rare-disease linkage (cohort genes)

Gene	Orphanet ID	Rare disease
IFRD1	Orphanet:98771	Spinocerebellar ataxia type 18

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
IFRD1	HGNC:5456	ENSG00000006652	O00458	Interferon-related developmental regulator 1	gencc

Cohort function summary

Lead sentence per gene, UniProt-curated.

Symbol	Protein name	Function (lead sentence)
IFRD1	Interferon-related developmental regulator 1	Could play a role in regulating gene activity in the proliferative and/or differentiative pathways induced by NGF.

Protein-family classification

Druggable: 0 · Difficult: 0 · Unknown: 1 · Druggable fraction: 0.0

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
Other/Unknown	1	1.8×	0.558

Per-gene assignment

Symbol	Family	Druggable?	EC	InterPro (top 3)
IFRD1	Other/Unknown	no		Interferon-rel_develop_reg_C, Interferon-rel_develop_reg_N, ARM-like

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
body of pancreas	1
jejunal mucosa	1
skeletal muscle tissue of rectus abdominis	1

Per-gene tissue summary (top 30)

Symbol	Bgee breadth	FANTOM5 breadth	SCXA	Top tissues
IFRD1	299	ubiquitous	marker	body of pancreas, jejunal mucosa, skeletal muscle tissue of rectus abdominis

Protein interactions among cohort

Intra-cohort edges: 0.

Hub genes (top 10 by interactor count)

Symbol	Interactor count
IFRD1	1,425

Structural data

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

AlphaFold-only cohort genes (top 30 by pLDDT)

Symbol	UniProt	pLDDT
IFRD1	O00458	84.46

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 0. Enrichment computed across 1 evidence-associated genes (0 with Reactome annotation).

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
myoblast fate determination	1	8426.0×	0.001	IFRD1
striated muscle tissue development	1	4213.0×	0.001	IFRD1
negative regulation of collateral sprouting	1	1532.0×	0.002	IFRD1
skeletal muscle tissue regeneration	1	887.0×	0.002	IFRD1
muscle cell differentiation	1	842.6×	0.002	IFRD1
negative regulation of axon extension	1	732.7×	0.002	IFRD1
adipose tissue development	1	401.2×	0.004	IFRD1
fat cell differentiation	1	181.2×	0.007	IFRD1
Wnt signaling pathway	1	99.7×	0.011	IFRD1
regulation of transcription by RNA polymerase II	1	11.7×	0.086	IFRD1

Therapeutics

Drug target analysis

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

Druggability breadth: 0 of 1 evidence-associated genes (0%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Top cohort targets by molecule count

Symbol	Molecules	Max phase
IFRD1	0	0

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 0.

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	0
D	Druggable family + AlphaFold only, no drug	0
E	Difficult family or no structure, no drug	1	IFRD1

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)
IFRD1	0	—

Clinical trials & evidence

Clinical trials

Clinical trials: 1.

Phase distribution (across all retrieved trials)

Phase	Trials
Not specified	1

Top trials by phase / activity

NCT	Phase	Status	Title
NCT01793168	Not specified	RECRUITING	Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford

Cohort genes: IFRD1