An interictal schizophrenia-like psychosis in an adult patient with 22q11.2 deletion syndrome.

In addition to causing polymalformative syndrome, 22q11.2 deletion can lead to various neuropsychiatric disorders including mental retardation, psychosis, and epilepsy. However, few reports regarding epilepsy-related psychosis in 22q11.2 deletion syndrome (22q11.2DS) exist. We describe the clinical characteristics and course of 22q11.2DS in a Japanese patient with comorbid mild mental retardation, childhood-onset localization-related epilepsy, and adult-onset, interictal schizophrenia-like psychosis. From a diagnostic viewpoint, early detection of impaired intellectual functioning and hyperprolinemia in patients with epilepsy with 22q11.2DS may be helpful in predicting the developmental timing of interictal psychosis. From a therapeutic viewpoint, special attention needs to be paid to phenytoin-induced hypocalcemia in this syndrome.