title: Genetic analysis of low BMI phenotype in the Utah Population Database.
abstract: The low body mass index (BMI) phenotype of less than 18.5 has been linked to medical and psychological morbidity as well as increased mortality risk. Although genetic factors have been shown to influence BMI across the entire BMI, the contribution of genetic factors to the low BMI phenotype is unclear. We hypothesized genetic factors would contribute to risk of a low BMI phenotype. To test this hypothesis, we conducted a genealogy data analysis using height and weight measurements from driver's license data from the Utah Population Data Base. The Genealogical Index of Familiality (GIF) test and relative risk in relatives were used to examine evidence for excess relatedness among individuals with the low BMI phenotype. The overall GIF test for excess relatedness in the low BMI phenotype showed a significant excess over expected (GIF 4.47 for all cases versus 4.10 for controls, overall empirical p-value<0.001). The significant excess relatedness was still observed when close relationships were ignored, supporting a specific genetic contribution rather than only a family environmental effect. This study supports a specific genetic contribution in the risk for the low BMI phenotype. Better understanding of the genetic contribution to low BMI holds promise for weight regulation and potentially for novel strategies in the treatment of leanness and obesity.
authors.affiliation: Laureate Institute for Brain Research, Tulsa, Oklahoma, United States of America ; University of Oklahoma College of Medicine, Tulsa, Tulsa, Oklahoma, United States of America.
authors.forename: William R
authors.initials: WR
authors.lastname: Yates
authors.affiliation: Eating Recovery Center, Denver, Colorado, United States of America.
authors.forename: Craig
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Laureate Institute for Brain Research, Tulsa, Oklahoma, United States of America ; University of Oklahoma College of Medicine, Oklahoma City, Oklahoma, United States of America.
authors.forename: Patrick
authors.initials: P
authors.lastname: McKee
authors.affiliation: Department of Medicine (Genetic Epidemiology), University of Utah School of Medicine, Salt Lake City, Utah, United States of America ; George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, Utah, United States of America.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Cannon-Albright
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D015992:Body Mass Index; D016208:Databases, Factual; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D014589:Utah; D055815:Young Adult