Screening for 22q11 deletions in a schizophrenia population.

Since the recognition that adults with velocardiofacial syndrome (VCFS), which is associated with hemizygous interstitial deletions of chromosome 22q11, frequently show psychotic symptoms, deletion of the 22q11.2 region has been proposed as a common genetic abnormality associated with schizophrenia. In studies of schizophrenia patients, such deletions have been detected in more than 1% of schizophrenics, indicating the likely presence of this deletion in a significant number of patients. In this study, we screened for 22q11.2 deletions by genotyping microsatellite markers in 300 schizophrenics and 300 normal controls. The 22q11.2 deletion was confirmed by fluorescent in situ hybridization (FISH). One patient with schizophrenia was found to have a 22q11.2 deletion. The patient was mildly retarded but did not have craniofacial, palatal, or cardiac malformations characteristic of VCFS. Our results indicate that 22q11.2 deletion does not contribute substantially to the development of schizophrenia in general. However, our findings establish the existence of physically near-normal individuals with 22q11.2 deletion among learning disabled or mildly retarded persons with schizophrenia.