The microdeletion at 15q11.2 was identified in the course of a study of the association of copy number variations (CNV) with schizophrenia. An Icelandic population based sample of 2160 trios and 5558 parent offspring pairs who had been genotyped on one of the Illumina chips was used to identify de novo deletion and duplication regions using dose (a probe-based intensity measure) and loss of heterozygosity analysis. The 15q11.2 deletion region was one of the 66 regions identified and subsequently investigated for association. In Iceland, 4 out of 646 schizophrenia patients and 58 out of 32,442 controls were shown to carry the deletion. In addition, one parent of a schizophrenia patient also carried the deletion. Each of the 63 persons with a deletion in this region met the criteria for inclusion in this phasing study.
