Early-onset Cerebellar Atrophy Associated with Mutation in the CACNA1A Gene

Mutations in the CACNA1A gene were described in familial hemiplegic migraine, episodic ataxia type 2, and spinocerebellar ataxia type 6. Familial hemiplegic migraine and episodic ataxia type 2 are caused by point mutations in the CACNA1A gene, and spinocerebellar ataxia type 6 develops as a result of a CAG triple expansion in exon 1 of the gene. Phenotypic variability and clinical overlap are well recognized. We describe a 3-year-old child with clinical and radiologic signs of early-onset cerebellar atrophy. The family history was significant for migraine, and in some members of the family, a diagnosis of hemiplegic migraine was established. The combination of cerebellar atrophy in our patient and the family history suggested involvement of the CACNA1A gene. The sequence analysis of genomic DNA from the proband identified heterozygosity for a mutation (Thr666Met) in the CACNA1A gene. Subsequently, his father, who was mildly affected, and two other relatives were demonstrated to carry the same mutation. Therefore, CACNA1A gene mutations should be considered in the differential diagnosis of congenital cerebellar atrophy.