Chromosome 22qII 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. Declaration of interest Funding from the PPP Healthcare Medical Trust, London, UK. Collection of probands in Bulgaria funded by the Janssen Research Foundation and in the UK by the Medica Research Council.