Infantile nystagmus and late onset ataxia associated with a CACNA1A mutation in the intracellular loop between s4 and s5 of domain 3

J. Self, C. Mercer, E. M.J. Boon, M. Murugavel, F. Shawkat, S. Hammans, P. Hodgkins, H. Griffiths, A. Lotery

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)


PurposeMutations in the 1A-subunit of the brain P/Q-type calcium channel gene CACNA1Aare responsible for spinocerebellar ataxia type 6 (SCA6), familial haemiplegic migraine (FHM) and episodic ataxia type 2 (EA2). Considerable clinical and genetic overlap exists between these 3 allelic disorders. Clinical findings are varied and may include nystagmus.ObjectiveTo study the clinical phenotype and identify a causative mutation in a family who presented when the youngest member was diagnosed with apparent isolated congenital nystagmus (age 3 months).Patients and Methods8 patients from one family underwent detailed clinical phenotyping comprising; ophthalmic and neurological examination, nystagmology, electrodiagnostic tests and brain imaging. The CACNA1Agene was screened for mutations by direct sequencing in one patient. Co-segregation of the disease and an identified sequence variation was shown using direct sequencing.ResultsPhenotyping revealed isolated atypical nystagmus in 4 family members and nystagmus in addition to late onset ataxia in 1 family member. Direct sequencing of the CACNA1Agene identified a novel missense mutation; (c.4110T>G p.Phe1370Leu (NM-000068.3)).ConclusionsWe have shown that a mutation in the intracellular domain between s4 and s5 of repeat 3 can cause atypical nystagmus/cerebellar phenotypes, including isolated nystagmus in an infant. We also illustrate the necessity for detailed examination of relatives in cases of apparent isolated congenital nystagmus.

Original languageEnglish
Pages (from-to)2251-2255
Number of pages5
Issue number12
Publication statusPublished - Dec 2009


  • Ataxia
  • Gene
  • Infantile
  • Mutation
  • Nystagmus

Cite this