Tomioka Y, et al. - Researchers here evaluated if variants of the gene coding for myo-inositol monophosphatase (IMPA2) are linked to age at onset of bipolar disorder (BD). Findings suggested the significant clinical implications of age at onset of bipolar disorder. Bipolar patients with early and late onset showed IMPA2 genetic variations. Increased diagnostic and therapeutical accuracy could be achieved by defining subgroup of patients. Results thereby provided evidence for genetic differences between early-onset BD and late-onset BD at the IMPA2 gene as well as clinical differences between subgroups with therapeutic implications.