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Mitochondrial dna depletion syndrome 7 (hepatocerebral type) (IOSCA)

Genes

  • Chromosome 10 open reading frame 2 (C10ORF2)

Summary

Mitochondrial DNA depletion syndrome 7 (hepatocerebral type), also known as infantile onset spinocerebellar ataxia (IOSCA syndrome), is a recessive progressive neurological disorder. The first symptoms develop in a previously healthy child during the first two years of life. The typical symptoms are cerebellar ataxia, athetosis, epilepsy, hypotonia, deterioration of hearing, ophtalmoplegia, and in females, primary hypogonadism. IOSCA syndrome was first described in Finland. The disease gene is C10orf2, situated in chromosome 10q24. It encodes a mitochondrial deoxyribonucleic acid (mtDNA)-specific helicase proteins Twinkle and Twinky (a rarer splice variant). Twinkle helicase is essential for mtDNA maintenance, and may be a key regulator of mtDNA copy number in mammals. Different mutations in C10orf2 gene cause autosomal dominant progressive external ophthalmoplegia (adPEO) (MIM 606075), a neuromuscular disorder sharing a spectrum of symptoms with IOSCA.

Links

UMLS Concept names

  • C1849096 SCA8, FORMERLY
  • C1849096 IOSCA
  • C1849096 MITOCHONDRIAL DNA DEPLETION SYNDROME 7 (HEPATOCEREBRAL TYPE)
  • C1849096 MTDPS7
  • C1849096 OPHTHALMOPLEGIA, HYPOTONIA, ATAXIA, HYPOACUSIS, AND ATHETOSIS
  • C1849096 OHAHA SYNDROME
  • C1849096 SPINOCEREBELLAR ATAXIA, INFANTILE, WITH SENSORY NEUROPATHY
  • C1849096 SPINOCEREBELLAR ATAXIA, INFANTILE-ONSET
  • C1849096 SPINOCEREBELLAR ATAXIA 8, FORMERLY

Selected publications

  • Nikali K, Suomalainen A, Saharinen J, Kuokkanen M, Spelbrink JN, Lönnqvist T, Peltonen L. Infantile onset spinocerebellar ataxia is caused by recessive mutations in mitochondrial proteins Twinkle and Twinky. Hum Mol Genet. 2005 Oct 15;14(20):2981-90. (Pubmed)
  • Tyynismaa H, Sembongi H, Bokori-Brown M, Granycome C, Ashley N, Poulton J, Jalanko A, Spelbrink JN, Holt IJ, Suomalainen A. Twinkle helicase is essential for mtDNA maintenance and regulates mtDNA copy number. Hum Mol Genet. 2004 Dec 15;13(24):3219-27 (Pubmed)