Bipolar spectrum disorders in patients diagnosed with velo-cardio-facial syndrome: does a hemizygous deletion of chromosome 22q11 result in bipolar affective disorder?

Abstract

The purpose of this study was to conduct a systematic assessment of psychiatric illness in patients diagnosed with velo-cardio-facial syndrome, a genetic syndrome that involves over 40 somatic anomalies, learning disabilities, and behavioral disorders and is associated with a microdeletion on chromosome 22q11. Subjects were referred for psychiatric diagnostic evaluation without regard to age or previous psychiatric history. In order to establish DSM-III-R consensus clinical diagnoses for patients who ranged in age from 5 to 34 years, the Diagnostic Interview for Children and Adolescents--Revised or the Structured Clinical Interview for DSM-III-R (SCID) was used. A review of available medical and psychiatric records and a clinical interview performed by two research psychiatrists to validate specific symptoms and syndromes reported in the Diagnostic Interview for Children and Adolescents--Revised and the SCID were used to elucidate the chronological appearance and duration of symptoms. Sixty-four percent (N = 16 of 25) of this unselected series of patients with velo-cardio-facial syndrome met DSM-III-R criteria for a spectrum of bipolar disorders with full syndromal onset in late childhood or early adolescence (mean age at onset = 12 years, SD = 3). In addition, 20% (N = 5) met DSM-III-R criteria for attention deficit hyperactivity disorder (ADHD), while 16% (N = 4) met criteria for attention deficit disorder without hyperactivity. In contrast to previous reports of a high prevalence of schizophrenia, none of the patients was diagnosed with schizophrenia, and only four had psychotic symptoms during a phase of their illness, all in their 20s or 30s. Given that the prevalence of bipolar disorder in the general population is estimated to be 1.5% and that the average age at onset is 24, these findings support an unusually strong association between velo-cardio-facial syndrome and early-onset bipolar disorder and suggest that a gene deleted at the 22q11 chromosomal locus may be involved in its pathogenesis. If confirmed, these findings may provide a new and fruitful line of investigation into the molecular basis of bipolar spectrum disorders.