A genomewide search finds major susceptibility loci for gallbladder disease on chromosome 1 in Mexican Americans.
Gallbladder disease (GBD) is one of the major digestive diseases. Its risk factors include age, sex, obesity, type 2 diabetes, and metabolic syndrome (MS). The prevalence of GBD is high in minority populations, such as Native and Mexican Americans. Ethnic differences, familial aggregation of GBD, and the identification of susceptibility loci for gallstone disease by use of animal models suggest genetic influences on GBD. However, the major susceptibility loci for GBD in human populations have not been identified. Using ultrasound-based information on GBD occurrence and a 10-cM gene map, we performed multipoint variance-components analysis to localize susceptibility loci for GBD. Phenotypic and genotypic data from 715 individuals in 39 low-income Mexican American families participating in the San Antonio Family Diabetes/Gallbladder Study were used. Two GBD phenotypes were defined for the analyses: (1) clinical or symptomatic GBD, the cases of cholecystectomies due to stones confirmed by ultrasound, and (2) total GBD, the clinical GBD cases plus the stone carriers newly diagnosed by ultrasound. With use of the National Cholesterol Education Program/Adult Treatment Panel III criteria, five MS risk factors were defined: increased waist circumference, hypertriglyceredemia, low high-density lipoprotein cholesterol, hypertension, and high fasting glucose. The MS risk-factor score (range 0-5) for a given individual was used as a single, composite covariate in the genetic analyses. After accounting for the effects of age, sex, and MS risk-factor score, we found stronger linkage signals for the symptomatic GBD phenotype. The highest LOD scores (3.7 and 3.5) occurred on chromosome 1p between markers D1S1597 and D1S407 (1p36.21) and near marker D1S255 (1p34.3), respectively. Other genetic locations (chromosomes 2p, 3q, 4p, 8p, 9p, 10p, and 16q) across the genome exhibited some evidence of linkage (LOD >or=1.2) to symptomatic GBD. Some of these chromosomal regions corresponded with the genetic locations of Lith loci, which influence gallstone formation in mouse models. In conclusion, we found significant evidence of major genetic determinants of symptomatic GBD on chromosome 1p in Mexican Americans.
Puppala
Sobha
S
Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX 78245-0549, USA. spuppala@darwin.sfbr.org
Dodd
Gerald D
GD
Fowler
Sharon
S
Arya
Rector
R
Schneider
Jennifer
J
Farook
Vidya S
VS
Granato
Richard
R
Dyer
Thomas D
TD
Almasy
Laura
L
Jenkinson
Christopher P
CP
Diehl
Andrew K
AK
Stern
Michael P
MP
Blangero
John
J
Duggirala
Ravindranath
R
D000328:Adult; D000368:Aged; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D005705:Gallbladder Diseases / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D015894:Genome, Human; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008126:Lod Score; D008297:Male; D017058:Mexican Americans / Q000235:genetics*; D008875:Middle Aged; D017720:Molecular Epidemiology; D009765:Obesity / Q000235:genetics; D010641:Phenotype; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000235:genetics; D012307:Risk Factors
D047908:Intracellular Signaling Peptides and Proteins; D047889:Receptors, Tumor Necrosis Factor, Type II; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C509248:Ptpn6 protein, mouse