Darier's disease (DD) is a rare, dominantly inherited skin disorder with abnormal keratinization and acantholysis. Recently, mutations of ATP2A2 encoding the sarco/endoplasmic reticulum Ca(2+)-ATPase type 2 isoform (SERCA2) have been reported in Caucasian DD families. In the present study, we examined the ATP2A2 gene mutations of three sporadic (AS1,AS3,AS4) and one familial (AS2) Japanese DD patients. Sequence analysis revealed that the patients had novel mutations, one nonsense mutation (AS1 (C613X)) and three single base changes leading to amino acid substitutions (AS2 (L321F), AS3 (I274V), and AS4 (M719I)). These results demonstrate that distinct ATP2A2 gene mutations are present in Japanese DD patients.