Exome sequencing of Japanese schizophrenia multiplex families supports the involvement of calcium ion channels

Most sequencing studies of schizophrenia (SCZ) have focused on de novo genetic variants due to interpretability. However, investigating shared rare variants among patients in the same multiplex family is also important. Relatively large-scale analyses of SCZ multiplex families have been done in Caucasian populations, but whether detected variants are also pathogenic in the Japanese population is unclear because of ethnic differences in rare variants. We performed whole-exome sequencing (WES) of 14 Japanese SCZ multiplex families. After quality control and filtering, we identified rare variants shared among affected persons within the same family. A gene ontology (GO) analysis was performed to identify gene categories possibly affected by these candidate variants. We found 530 variants in 486 genes as potential candidate variants from the 14 SCZ multiplex families examined. The GO analysis demonstrated significant enrichment in calcium channel activity. This study provides supporting evidence that calcium ion channel activity is involved in SCZ. WES of multiplex families is a potential means of identifying disease-associated rare variants for SCZ.