Glutamate decarboxylase is not genetically linked to pyridoxine-dependent seizures

Several aspects of pyridoxine-dependent seizure (PDS) suggest a mutation af fecting glutamate decarboxylase (GAD) as a possible cause. To examine the p ossibility of GAD linkage with PDS, the authors performed genotype analyses of three families using polymorphic markers near the GAD genes (GAD1 and G AD2). In each family, the affected siblings exhibited different genotypes f or the GAD2 gene; in two families the GAD1 genotype was disparate. These fi ndings suggest that a mutation of GAD is not directly involved in all cases of PDS.