OBJECTIVES: To characterize the nature of CACNA1A mutation in a previously unreported family with episodic ataxia type 2 (EA2) and to better delineate EA2 clinical features. BACKGROUND: Episodic ataxia type 2 is an autosomal dominant disorder characterized by the recurrence of acetazolamide-responsive spells of cerebellar ataxia, usually starting during childhood or adolescence. The mutated gene, CACNA1A, is located on chromosome 19 and encodes the alpha1A subunit voltage-dependent calcium channel. So far, most CACNA1A mutations detected in patients with EA2 have led to a truncated CACNA1A protein, whereas missense mutations cause familial hemiplegic migraine. METHODS: All 47 exons of CACNA1A were screened by a combination of single-strand conformer polymorphism and sequencing analysis. RESULTS: A CACNA1A missense mutation, Glu 1757 Lys, was identified. It was absent in 200 control chromosomes. It is predicted to result in an amino acid substitution at a highly phylogenetically conserved position, within a domain that plays a major role in the function of the channel. CONCLUSIONS: The Glu 1757 Lys missense mutation is likely to be pathogenic, causing episodic ataxia within a family whose phenotype is indistinguishable from EA2 except for a slightly later age of onset. These data strongly suggest that additional work is needed to fully establish genotype/phenotype correlations for CACNA1A mutations.
OBJECTIVES: To characterize the nature of CACNA1A mutation in a previously unreported family with episodic ataxia type 2 (EA2) and to better delineate EA2 clinical features. BACKGROUND:Episodic ataxia type 2 is an autosomal dominant disorder characterized by the recurrence of acetazolamide-responsive spells of cerebellar ataxia, usually starting during childhood or adolescence. The mutated gene, CACNA1A, is located on chromosome 19 and encodes the alpha1A subunit voltage-dependent calcium channel. So far, most CACNA1A mutations detected in patients with EA2 have led to a truncated CACNA1A protein, whereas missense mutations cause familial hemiplegic migraine. METHODS: All 47 exons of CACNA1A were screened by a combination of single-strand conformer polymorphism and sequencing analysis. RESULTS: A CACNA1A missense mutation, Glu 1757 Lys, was identified. It was absent in 200 control chromosomes. It is predicted to result in an amino acid substitution at a highly phylogenetically conserved position, within a domain that plays a major role in the function of the channel. CONCLUSIONS: The Glu 1757 Lys missense mutation is likely to be pathogenic, causing episodic ataxia within a family whose phenotype is indistinguishable from EA2 except for a slightly later age of onset. These data strongly suggest that additional work is needed to fully establish genotype/phenotype correlations for CACNA1A mutations.
Authors: J Haan; E E Kors; Kaate R J Vanmolkot; Arn M J M van den Maagdenberg; Rune R Frants; M D Ferrari Journal: Curr Pain Headache Rep Date: 2005-06
Authors: Robert S Raike; Holly B Kordasiewicz; Randall M Thompson; Christopher M Gomez Journal: Mol Cell Neurosci Date: 2006-12-11 Impact factor: 4.314
Authors: M A Kaunisto; H Harno; M Kallela; H Somer; R Sallinen; E Hämäläinen; P J Miettinen; J Vesa; A Orpana; A Palotie; M Färkkilä; M Wessman Journal: Neurogenetics Date: 2003-10-07 Impact factor: 2.660