Schizophrenic Phenotype and Therapeutic Course Associated With Chromosome 22q11.2 Deletion in a Cohort Without Prior Diagnosis of Chromosome 22q11.2 Deletion Syndrome

Chromosome 22q11.2 deletion is the greatest single genetic factor predisposing to schizophrenia. The prevalence of schizophrenia reported ranges from 2% to 30% in patients with chromosome 22q11.2 deletion syndrome with a still discussed phenotype. In the present study 1177 patients diagnosed with schizophrenia, schizoaffective disorder or affective disorder according to ICD-10 criteria, none of which had been diagnosed with chromosome 22q11.2 deletion syndrome before, were screened for the chromosome 22q11.2 deletion or duplication applying TaqMan real-time PCR. In six patients a deletion was found. The prevalence of the chromosome 22q11.2 deletion in the study population was 0.5%. According to ICD-10, three patients were diagnosed with paranoid schizophrenia and three with schizoaffective disorder. Applying the differentiated criteria of Karl Leonhard, four patients were diagnosed with affect-laden paraphrenia. Patients were treated with antipsychotics with varying success and the course of the disease ranged from full remission to severe residuum. Given the relevant prevalence of chromosome 22q11.2 deletion in an unselected population like the present one, a general screening of schizophrenic patients is discussed given the potentially severe, but treatable symptoms of the syndrome.