Genome-wide linkage scan in Gullah-speaking African American families with type 2 diabetes: the Sea Islands Genetic African American Registry (Project SuGAR).
OBJECTIVE
The Gullah-speaking African American population from the Sea Islands of South Carolina is characterized by a low degree of European admixture and high rates of type 2 diabetes and diabetic complications. Affected relative pairs with type 2 diabetes were recruited through the Sea Islands Genetic African American Registry (Project SuGAR).


METHODS
We conducted a genome-wide linkage scan, genotyping 5,974 single nucleotide polymorphisms in 471 affected subjects and 50 unaffected relatives from 197 pedigrees. Data were analyzed using a multipoint engine for rapid likelihood inference and ordered subsets analyses (OSAs) for age at type 2 diabetes diagnosis, waist circumference, waist-to-hip ratio, and BMI. We searched for heterogeneity and interactions using a conditional logistic regression likelihood approach.


RESULTS
Linkage peaks on chromosome 14 at 123-124 cM were detected for type 2 diabetes (logarithm of odds [LOD] 2.10) and for the subset with later age at type 2 diabetes diagnosis (maximum LOD 4.05). Two linkage peaks on chromosome 7 were detected at 44-45 cM for type 2 diabetes (LOD 1.18) and at 78 cM for type 2 diabetes (LOD 1.64) and the subset with earlier age at type 2 diabetes diagnosis (maximum LOD 3.93). The chromosome 14 locus and a peak on 7p at 29.5 cM were identified as important in the multilocus model. Other regions that provided modest evidence for linkage included chromosome 1 at 167.5 cM (LOD 1.51) and chromosome 3 at 121.0 cM (LOD 1.61).


CONCLUSIONS
This study revealed a novel type 2 diabetes locus in an African American population on 14q that appears to reduce age of disease onset and confirmed two loci on chromosome 7.
Sale
Michèle M
MM
Center for Public Health Genomics, University of Virginia, Charlottesville, Virginia, USA. msale@virginia.edu
Lu
Lingyi
L
Spruill
Ida J
IJ
Fernandes
Jyotika K
JK
Lok
Kerry H
KH
Divers
Jasmin
J
Langefeld
Carl D
CD
Garvey
W Timothy
WT
D001741:Black or African American / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000235:genetics*; D005192:Family Health; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D055106:Genome-Wide Association Study / Q000379:methods*; D005838:Genotype; D006801:Humans; D008126:Lod Score; D020641:Polymorphism, Single Nucleotide; D012042:Registries / Q000706:statistics & numerical data; D013022:South Carolina