Association of infantile convulsions with paroxysmal dyskinesias (ICCA syndrome): confirmation of linkage to human chromosome 16p12-q12 in a Chinese family

We have studied one family of Chinese origin, in which benign infantile con vulsions and paroxysmal choreoathetosis (of the dystonic form) were co-inhe rited as a single autosomal dominant trail. This association is specific to ICCA syndrome, which we have recently described in four French families. S ome patients in the new family also exhibit recurrence of epileptic seizure s at a much later age, making the ICCA syndrome in this family atypical. DN A samples isolated from this family of 22 members (9 affected) have been te sted with genetic markers at chromosome 16p12-q12, in which region the ICCA syndrome has previously been linked. Confirmation of linkage to this peric entromeric region of human chromosome 16 has been obtained and no critical meiotic recombination event has been detected in the ICCA region. This resu lt suggests that, in contrast to marked clinical heterogeneity, the associa tion of infantile convulsions with paroxysmal dyskinetic movements could be genetically homogeneous.