Runs of homozygosity, copy number variation, and risk for depression and suicidal behavior in an Arab Bedouin kindred

Nadine M. Melhem*, Sami Hamdan, Lambertus Klei, Shawn Wood, Jamie Zelazny, Amos Frisch, Abraham Weizman, Miri Carmel, Elena Michaelovsky, Ilana Farbstein, Danuta Wasserman, Muhammad El-Heib, Robert Ferrell, Alan Apter, Bernie Devlin, David Brent

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Objectives Inbreeding increases the probability of homozygosity of deleterious alleles. Inbreeding and runs of homozygosity (ROH) are associated with an increased risk for disease phenotypes, including schizophrenia and other psychiatric disorders. The effects of inbreeding, ROH, homozygous deletions, and other copy number variations (CNVs) on risk for depression and suicide attempt (SA) were quantified in an Arab Bedouin Kindred. Methods We carried out genetic analyses of 439 individuals from an Arab kindred with high rates of depression and suicidal behavior. We obtained complete ascertainment of SAs and first-degree relatives of individuals who have attempted or died by suicide. Results We found extensive regions of ROH. On average, 5% of the genome is covered by ROH for these individuals, two-fold higher than ROH rates for individuals from populations of European ancestry. Inbreeding and total length of ROH were not associated with risk for depression or attempt. For CNVs, an increased number of duplications more than 500 kb was associated with an increased risk for attempt (odds ratio: 2.9; P=0.01; 95% confidence interval: 1.3-6.6). Although not significant after correction for multiple testing, the risk for SA appears to increase with copy number for a CNV on chromosome 9p24.1. This possibility is intriguing because the CNV covers GLDC, which encodes glycine dehydrogenase that binds to glycine, a co-agonist at N-methyl-D-aspartate glutamate receptors, and is involved in glutamatergic neurotransmission. Conclusion Our findings add to the growing evidence of genetic risk factors that act pleiotropically to increase the risk for several neuropsychiatric disorders, including depression and SA, irrespective of ancestry.

Original languageEnglish
Pages (from-to)169-177
Number of pages9
JournalPsychiatric Genetics
Issue number5
StatePublished - 31 May 2017


FundersFunder number
National Institute of Mental HealthK01MH077930
Pittsburgh Foundation
American Foundation for Suicide Prevention
Klingenstein Third Generation Foundation
National Alliance for Research on Schizophrenia and Depression
United States-Israel Binational Science Foundation
Knut och Alice Wallenbergs Stiftelse


    • Arab population
    • Copy number variation
    • Depression
    • Inbreeding
    • Pedigree
    • Runs of homozygosity
    • Suicidal behavior


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