Chromosome 22q11 deletions, velo-cardio-facial syndrome and early-onset psychosis: Molecular genetic study

Background: Velo-cardio-facial syndrome (VCFS) is associated with interstitial deletions of chromosome 22q11. About 30% of patients with VCFS have psychosis, and the rate of these deletions in schizophrenia has been reported to be about 1%. Even higher rates of VCFS deletions have been reported for childhood-onset schizophrenia. Aims: To test the hypothesis that there is an increased rate of VCFS among patients with early-onset psychosis (age at onset < 18 years). We screened 192 early-onset patients and 329 patients with adult-onset schizophrenia. Method: We genotyped the patients and 444 healthy controls for hemizygosity of five microsatellite markers and one single nucleotide polymorphism that map to the 22q11-deleted region. Results: One patient had a VCFS deletion, confirmed with semi-quantitative polymerase chain reaction. None of the controls showed a pattern of genotypes consistent with hemizygosity. Conclusions: VCFS may be less frequent among patients with psychosis than previously suggested; this rate is not increased among early-onset patients.