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Background: Obsessive-compulsive disorder (OCD) has a complex etiology involving both genetic and environmental factors. However, the genetic causes of OCD are largely unknown, despite the identification of several promising candidate genes and linkage regions., Methods: Our objective was to conduct genetic linkage studies of the type of OCD thought to have the strongest genetic etiology (i.e., childhood-onset OCD), in 33 Caucasian families with ≥2 childhood-onset OCD-affected individuals from the United States (n = 245 individuals with genotype data). Parametric and nonparametric genome-wide linkage analyses were conducted with Morgan and Merlin in these families using a selected panel of single nucleotide repeat polymorphisms from the Illumina 610-Quad Bead Chip. The initial analyses were followed by fine-mapping analyses in genomic regions with initial heterogeneity logarithm of odds (HLOD) scores of ≥2.0., Results: We identified five areas of interest (HLOD score ≥2) on chromosomes 1p36, 2p14, 5q13, 6p25, and 10p13. The strongest result was on chromosome 1p36.33-p36.32 (HLOD = 3.77, suggestive evidence for linkage after fine mapping). At this location, several of the families showed haplotypes co-segregating with OCD., Conclusions: The results of this study represent the strongest linkage finding for OCD in a primary analysis to date and suggest that chromosome 1p36, and possibly several other genomic regions, may harbor susceptibility loci for OCD. Multiple brain-expressed genes lie under the primary linkage peak (approximately 4 megabases in size). Follow-up studies, including replication in additional samples and targeted sequencing of the areas of interest, are needed to confirm these findings and to identify specific OCD risk variants., (Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Background: There is limited research regarding the nature and prevalence of obsessive-compulsive disorder (OCD) among various racial and ethnic subpopulations within the United States, including African Americans and blacks of Caribbean descent. Although heterogeneity within the black population in the United States has largely been ignored, notable differences exist between blacks of Caribbean descent and African Americans with respect to ethnicity, national heritage, and living circumstances. This is the first comprehensive examination of OCD among African Americans and blacks of Caribbean descent., Methods: Data from the National Survey of American Life, a national household probability sample of African Americans and Caribbean blacks in the United States, were used to examine rates of OCD among these groups., Results: Lifetime and 12-month OCD prevalence estimates were very similar for African Americans and Caribbean blacks. Persistence of OCD and rates of co-occurring psychiatric disorders were very high and also similar between African American and Caribbean black respondents. Both groups had high levels of overall mental illness severity and functional impairment. Use of services was low for both groups, particularly in specialty mental health settings. Use of anti-obsessional medications was also rare, especially among the Caribbean black OCD population., Conclusions: OCD among African Americans and Caribbean blacks is very persistent, often accompanied by other psychiatric disorders, and is associated with high overall mental illness severity and functional impairment. It is also likely that very few blacks in the United States with OCD are receiving evidence-based treatment and thus considerable effort is needed to bring treatment to these groups.