mitochondrial DNA depletion syndrome 7 (hepatocerebral type)
Findings
No curated finding names mitochondrial DNA depletion syndrome 7 (hepatocerebral type) yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Infantile-onset spinocerebellar ataxia (IOSCA) is a hereditary neurological disorder with early and severe involvement of both the peripheral and central nervous systems. It has only been described in Finnish families.
Definition from the Mondo Disease Ontology (MONDO:0010060), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Infantile onset · Progressive
HPO, annotations 2026-09-02
Features
27 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- AreflexiaHPOHP:0001284
- 2 of 2 reported patients
- AthetosisHPOHP:0002305
- 2 of 2 reported patients
- Decreased number of large peripheral myelinated nerve fibersHPOHP:0003387
- 2 of 2 reported patients
- EncephalopathyHPOHP:0001298
- 2 of 2 reported patients
- Epilepsia partialis continuaHPOHP:0012847
- 2 of 2 reported patients
- HypotoniaHPOHP:0001252
- 2 of 2 reported patients
- Involuntary movementsHPOHP:0004305
Show the remaining 15
- Abnormality of movementHPOHP:0100022
- Very frequent (80% to 99% of cases)
- Abnormality of the autonomic nervous systemHPOHP:0002270
- Very frequent (80% to 99% of cases)
- AtaxiaHPOHP:0001251
- 1 of 2 reported patients
- Very frequent (80% to 99% of cases)
- Diminished deep tendon reflexHPOHP:0001315
- Very frequent (80% to 99% of cases)
- Hearing impairmentHPOHP:0000365
- 1 of 2 reported patients
- Very frequent (80% to 99% of cases)
- Optic atrophyHPOHP:0000648
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- TWNKHGNC:1160
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2020
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
Other names
6 names
Resolves to: mitochondrial DNA depletion syndrome 7 (hepatocerebral type)
- Also called
- autosomal recessive degenerative and progressive cerebellar ataxia caused by mutation in TWNKIOSCAmitochondrial DNA depletion syndrome type 7OHAHA syndromeophthalmoplegia-hypotonia-ataxia-hypoacusis-athetosis syndromeTWNK autosomal recessive degenerative and progressive cerebellar ataxia