A Quantitative Trait Locus on Chromosome 13q Affects Fasting Glucose Levels in Hispanic Children

Objective: The prevalence of childhood obesity has increased dramatically in the United States. Early presentation of type 2 diabetes has been observed in children and adolescents, especially in the Hispanic population. The genetic contribution of glucose homeostasis related to childhood obesity is poorly understood. The objective of this study was to localize quantitative trait loci influencing fasting serum glucose levels in Hispanic children participating in the Viva La Familia Study. Design: Subjects were 1030 children ascertained through an overweight child from 319 Hispanic families. Fasting serum glucose levels were measured enzymatically, and genetic linkage analyses were conducted using SOLAR software. Results: Fasting glucose was heritable, with a heritability of 0.62 ± 0.08 (P < 0.01). Genome-wide scan mapped fasting serum glucose to markers D13S158–D13S173 on chromosome 13q (LOD score of 4.6). A strong positional candidate gene is insulin receptor substrate 2, regulator of glucose homeostasis and a candidate gene for obesity. This region was reported previously to be linked to obesity- and diabetes-related phenotypes. Conclusions: A quantitative trait locus on chromosome 13q contributes to the variation in fasting serum glucose levels in Hispanic children at high risk for obesity.