Genetic alteration of the DCX gene in Japanese patients with subcortical laminar heterotopia or isolated lissencephaly sequence

We examined mutations of the doublecortin (DCX) gene, which is responsible for X-linked subcortical laminar heterotopia (SCLH) and lissencephaly, in e ight unrelated Japanese patients, four with SCLH and four with isolated lis sencephaly sequence (ILS). Polymerase chain reaction (PCR) disclosed a dele tion of part of the DCX gene in one male ILS patient. Single-strand conform ational polymorphism analysis and subsequent sequence analysis were carried out in the remaining seven patients. One male ILS patient had a nonsense m utation in exon V, which would result in premature termination of the gene product. One female SCLH patient had a missense mutation in exon IV. Our re sults indicate that in the Japanese, as has been seen elsewhere, abnormalit y of the DCX gene is the common cause of SCLH and ILS.