title: Corpus callosum size is highly heritable in humans, and may reflect distinct genetic influences on ventral and rostral regions.
abstract: Anatomical differences in the corpus callosum have been found in various psychiatric disorders, but data on the genetic contributions to these differences have been limited. The current study used morphometric MRI data to assess the heritability of corpus callosum size and the genetic correlations among anatomical sub-regions of the corpus callosum among individuals with and without mood disorders. The corpus callosum (CC) was manually segmented at the mid-sagittal plane in 42 women (healthy, n = 14; major depressive disorder, n = 15; bipolar disorder, n = 13) and their 86 child or adolescent offspring. Four anatomical sub-regions (CC-genu, CC2, CC3 and CC-splenium) and total CC were measured and analyzed. Heritability and genetic correlations were estimated using a variance components method, with adjustment for age, sex, diagnosis, and diagnosis x age, where appropriate. Significant heritability was found for several CC sub-regions (P<0.01), with estimated values ranging from 48% (splenium) to 67% (total CC). There were strong and significant genetic correlations among most sub regions. Correlations between the genu and mid-body, between the genu and total corpus callosum, and between anterior and mid body were all >90%, but no significant genetic correlations were detected between ventral and rostral regions in this sample. Genetic factors play an important role in corpus callosum size among individuals. Distinct genetic factors seem to be involved in caudal and rostral regions, consistent with the divergent functional specialization of these brain areas.
authors: Genetic Basis of Mood & Anxiety Disorders Section, Human Genetics Branch, National Institute of Mental Health, NIH, DHHS, Bethesda, Maryland, United States of America.
authors: Girma
authors: G
authors: Woldehawariat
authors: Section on Behavioral Endocrinology, National Institute of Mental Health, NIH, DHHS, Bethesda, Maryland, Unites States of America.
authors: Pedro E
authors: PE
authors: Martinez
authors: VISN 22 Network Office, Long Beach, California, United States of America.
authors: Peter
authors: P
authors: Hauser
authors: Center for Information Technology, National Institutes of Health, Bethesda, Maryland, United States of America.
authors: David M
authors: DM
authors: Hoover
authors: Laureate Institute for Brain Research and the University of Oklahoma College of Medicine, Tulsa, Oklahoma, United States of America.
authors: Wayne W C
authors: WW
authors: Drevets
authors: Genetic Basis of Mood & Anxiety Disorders Section, Human Genetics Branch, National Institute of Mental Health, NIH, DHHS, Bethesda, Maryland, United States of America.
authors: Francis J
authors: FJ
authors: McMahon
mesh_terms: D000293:Adolescent; D000328:Adult; D001714:Bipolar Disorder / Q000235:genetics / Q000473:pathology*; D016022:Case-Control Studies; D002648:Child; D003337:Corpus Callosum / Q000033:anatomy & histology*; D003866:Depressive Disorder / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010375:Pedigree; D019655:Quantitative Trait, Heritable