Extremely rare variants in miRNA genes on the X-chromosome may strongly predispose people to schizophrenia, according to researchers at the City of Hope National Medical Center. The findings appear in PLoS ONE in a paper titled “Evidence for X-Chromosomal Schizophrenia Associated with microRNA Alterations.”
In this study the sequences of 59 miRNA genes on the X-chromosome were determined in 193 men with schizophrenia and 191 without the disease. Men were chosen for this study, because they are much more commonly affected by mutations in genes on the X-chromosome.
Eight ultrarare variants in eight distinct miRNA genes were detected in 4% of the men with schizophrenia, while none were detected in normal men. Biochemical tests of the ultrarare variants demonstrated alterations in miRNA function or expression levels.