a1 Department of Psychiatry and Behavioral Sciences, NorthShore University HealthSystem Research Institute, Evanston, IL, USA
a2 Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL, USA
a3 Department of Human Genetics, University of Miami, Miami, FL, USA
a4 Department of Psychology, Pennsylvania State University, University Park, PA, USA
a5 Department of Psychology, University of Essex, Colchester, England, UK
a6 Department of Psychiatry, Icahn School of Medicine at Mount Sinai, Elmhurst, NY, USA
a7 Department of Sociomedical Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
a8 Department of Psychology, Northwestern University, Evanston, IL, USA
Background Findings from family and twin studies support a genetic contribution to the development of sexual orientation in men. However, previous studies have yielded conflicting evidence for linkage to chromosome Xq28.
Method We conducted a genome-wide linkage scan on 409 independent pairs of homosexual brothers (908 analyzed individuals in 384 families), by far the largest study of its kind to date.
Results We identified two regions of linkage: the pericentromeric region on chromosome 8 (maximum two-point LOD = 4.08, maximum multipoint LOD = 2.59), which overlaps with the second strongest region from a previous separate linkage scan of 155 brother pairs; and Xq28 (maximum two-point LOD = 2.99, maximum multipoint LOD = 2.76), which was also implicated in prior research.
Conclusions Results, especially in the context of past studies, support the existence of genes on pericentromeric chromosome 8 and chromosome Xq28 influencing development of male sexual orientation.
(Received April 28 2014)
(Revised September 02 2014)
(Accepted September 07 2014)
(Online publication November 17 2014)
c1 Address for correspondence: A. R. Sanders, M.D., Department of Psychiatry and Behavioral Sciences, NorthShore University HealthSystem Research Institute, 1001 University Place, Evanston, IL 60201, USA. (Email: email@example.com)