Mapping the gene for acetazolamide responsive hereditary paryoxysmal cerebellar ataxia to chromosome 19p

Acetazolamide responsive hereditary paroxysmal cerebellar ataxia (APCA) is a rare autosomal dominant disorder characterized by attacks of cerebellar ataxia and dysarthria with normal or near normal neurologic function between attacks. A genome-wide search using polymorphic di- and tri-nucleotide repeats was initiated and the APCA locus was found to be linked to the short arm of chromosome 19 in two large kindreds. The microsatellite marker UT705 was found to be linked to the APCA locus with two point analysis yielding a maximum lod score of 8.20 at theta max = 0.000 in a five generation pedigree. Linkage to this region was confirmed in a second kindred. The absence of known candidate genes in the region may necessitate a positional cloning approach in order to identify the gene for this disorder.