First cases of pyridoxine-dependent epilepsy in Bulgaria: novel mutation in the ALDH7A1 gene.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive disorder characterized by intractable seizures in neonates and infants. The seizures cannot be controlled with antiepileptic medications but respond both clinically and electrographically to large daily supplements of pyridoxine (vitamin B6). PDE is caused by mutations in the ALDH7A1 gene. Molecular genetic analysis of the ALDH7A1 gene was performed in seven patients, referred with clinical diagnosis of PDE. Mutations were detected in a dizygotic twin pair and a non-related boy with classical form of PDE. Direct sequencing of the ALDH7A1 gene revealed one novel (c.297delG, p.Trp99*) and two already reported (c.328C>T, p.Arg110*; c.584A>G, p.Asn195Ser) mutations. Here, we report the first genetically proven cases of PDE in Bulgaria.