CNV Screening of Saudi Schizophrenia
Genome-wide association studies have discovered common polymorphisms in regions associated with schizophrenia. No genome-wide analyses have been performed in Saudi schizophrenia subjects. Genome-wide genotyping data from 136 Saudi cases and 97 Saudi controls in addition to 4,625 United States/European were studied and copy number variants (CNVs) were examined across the genomes. A hidden Markov model approach was used to call CNVs. CNVs in schizophrenia cases were twice as large on average than CNVs in the controls (p = 0.04). The analyses focused on extremely large >250 kilobases CNVs or homozygous deletions of any size. One extremely large deletion was noted in a single case (16.5 megabases on chr10). Two cases had an 814 kb duplication of chromosome 7 spanning a cluster of genes, including circadian-related loci, and two other cases had 277 kb deletions of chromosome 9 encompassing olfactory receptors gene family. A single case carried a CNV that was previously associated with schizophrenia, namely a 16p11 proximal. Runs of homozygosity (ROHs) were analyzed across the genome to investigate any correlation with schizophrenia risk. While rates and sizes of these ROHs were similar in cases and controls, we identified ten regions where cases had more significant ROHs versus controls.