Screening for 22q11 deletions in a schizophrenia population T. Arinami a, * , T. Ohtsuki a , K. Takase a , H. Shimizu b , T. Yoshikawa c , H. Horigome d , J. Nakayama a,d , M. Toru e a Department of Medical Genetics, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan b Hokushin General Hospital, Nakano 383-8505, Japan c Laboratory for Molecular Psychiatry, RIEKN Brain Science Institute, Wako 351-0198, Japan d Department of Pediatrics, Institute of Clinical Medicine, University of Tsukuba, Tsukuba 305-8575, Japan e Department of Neuropsychiatry, Tokyo Medical and Dental University School of Medicine, Tokyo 113-8510, Japan Received 21 October 2000; accepted 4 December 2000 Abstract 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 signi®cant 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 con®rmed by ¯uorescent 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 malforma- tions characteristic of VCFS. Our results indicate that 22q11.2 deletion does not contribute substantially to the development of schizophrenia in general. However, our ®ndings establish the existence of physically near-normal individuals with 22q11.2 deletion among learning disabled or mildly retarded persons with schizophrenia. q 2001 Elsevier Science B.V. All rights reserved. Keywords: Schizophrenia; Chromosome 22q11; Velocardiofacial syndrome; FISH; Microsatellite 1. Introduction Interstitial deletions of chromosome 22q11 are associated with several genetic syndromes and anomalies including velocardiofacial syndrome VCFS), DiGeorge syndrome DGS), and conotruncal anomaly face syndrome. More than 80% of VCFS patients had 22q11 deletions, and more than 90% of the deletions encompassed similar 3-Mb regions Carlson et al., 1997a,b). There was no correlation between the presence or size of the deletion and phenotype including psychiatric disorders Carlson et al., 1997a,b). The estimated prevalence of the dele- tion is 1 in 4500 in the general population du Montcel et al., 1996), with sporadic occurrence representing the majority of cases. The term `22q11 deletion syndrome' has been proposed as a replacement for the collective acronym `CATCH 22', which empha- sizes the more severe congenital physical anomalies and may hinder identi®cation of adults with 22q11 deletion syndromes. Emphasis on the physical anoma- lies could also prevent diagnosticians from noting Schizophrenia Research 52 2001) 167±170 0920-9964/01/$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. PII: S0920-996400)00192-4 www.elsevier.com/locate/schres * Corresponding author. Tel.: 181-298-53-3352; fax: 181-298- 53-3333. E-mail address: tarinami@md.tsukuba.ac.jp T. Arinami).