The genetic architecture of lipoprotein subclasses in Gullah-speaking African American families enriched for type 2 diabetes: the Sea Islands Genetic African American Registry (Project SuGAR).

We sought to partition the genetic and environmental influences on lipoprotein subclasses and identify genomic regions that may harbor genetic variants that influence serum lipoprotein levels in a sample of Gullah-speaking African-Americans. We genotyped 5,974 SNPs in 979 subjects from 418 pedigrees and used the variance component approach to compute heritability estimates, genetic and environmental correlations, and linkage analyses for selected lipoprotein subclasses. The highest heritability estimate was observed for large VLDL particle concentration (0.56 +/- 0.14). Mean LDL particle size and small LDL particle concentration (-0.94) had the strongest genetic correlation estimate. The highest logarithm of odds (LOD) score detected (3.0) was on chromosome 6p24 for small LDL particle concentration. The strongest signal, obtained with the reduced sample of diabetic individuals only, was observed on chromosome 20p13 for small LDL particle concentration. The highest bivariate linkage signal (LOD 2.4) was observed on chromosome 6p24 for mean LDL particle size and small LDL particle concentration. Our results suggest a significant genetic contribution to multiple lipoprotein subclasses studied in this sample and that novel loci on chromosomes 6, 10, 16, and 20 may harbor genes contributing to small, atherogenic LDL particle concentration and large, triglyceride-rich VLDL particle concentration.