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Assessment of the frequency of the 22q11 deletion in Afrikaner schizophrenic patients
Author(s) -
Wiehahn G.J.,
Bosch G.P.,
du Preez R.R.,
Pretorius H.W.,
Karayiorgou M.,
Roos J.L.
Publication year - 2004
Publication title -
american journal of medical genetics part b: neuropsychiatric genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.393
H-Index - 126
eISSN - 1552-485X
pISSN - 1552-4841
DOI - 10.1002/ajmg.b.20168
Subject(s) - schizophrenia (object oriented programming) , schizoaffective disorder , deletion syndrome , locus (genetics) , population , chromosome , psychosis , genetics , fluorescence in situ hybridization , biology , in situ hybridisation , medicine , phenotype , psychiatry , gene , environmental health
A hemizygous deletion of the q11 band on chromosome 22 occurs in 1 of every 5,950 live births (0.017%). The deletion is mediated by low copy repeats (LCRs) flanking this locus. Presence of the deletion is associated with variable phenotypic expression, which can include distinctive facial dysmorphologies, congenital heart disease and learning disabilities. An unusually high percentage of individuals with this deletion (25–30%) have been described to develop schizophrenia or schizoaffective disorder. In previous studies, the prevalence of the 22q11 deletion in patients with schizophrenia was found to be approximately 2% in Caucasian adults and 6% in childhood‐onset cases. Both these frequencies represent a dramatic increase from the prevalence of the deletion in the general population. In this study, we investigate the occurrence of the 22q11 deletion in an independent sample of schizophrenic patients of Afrikaner origin. We first ascertained a sample of 85 patients who meet full diagnostic criteria for schizophrenia for presence of two or more of the clinical features associated with presence of the 22q11 deletion. A group of six patients (7%) met these criteria. This group was subjected to fluorescent in situ hybridization (FISH) and presence of the 22q11 deletion was confirmed for two subjects. Our study therefore confirms the previously reported rate of 2% frequency of the 22q11 deletion in adult schizophrenic patients and provides a two‐stage screening protocol to identify these patients. © 2004 Wiley‐Liss, Inc.