Incorporating prior biological information in linkage studies increases power and limits multiple testing

Area of Science:

• Genetics
• Developmental Biology
• Bioinformatics

Background:

• The enteric nervous system (ENS) development involves complex genetic regulation.
• Identifying genetic loci influencing ENS gene expression is crucial for understanding related disorders.
• Previous studies have mapped Hirschsprung disease loci to chromosome 9q31.

Purpose of the Study:

• To identify expression phenotype quantitative trait loci (eQTLs) for genes involved in ENS development.
• To locate a potential master regulator locus influencing multiple ENS-related genes.
• To evaluate a novel strategy for genetic linkage analysis combining genome-wide and candidate region approaches.

Main Methods:

• Utilized the Genetic Analysis Workshop 15 Problem 1 dataset.
• Performed genome-wide linkage analysis on a limited set of candidate ENS genes.
• Extended analysis to correlated traits within promising candidate regions.
• Employed univariate and bivariate variance-component linkage analysis.

Main Results:

• Identified a significant "master regulator" locus on chromosome 9q31.
• Observed LOD scores > 2 for one trait in genome-wide analysis and two traits in follow-up analysis.
• Bivariate linkage analysis revealed a maximum multipoint LOD score of 5.17, supporting a common regulatory locus.
• The identified region overlaps with a known Hirschsprung disease susceptibility locus.

Conclusions:

• A novel strategy of focused genome-wide analysis followed by trait expansion proved effective.
• A potential master regulatory locus on chromosome 9q31 influences ENS gene expression.
• This finding has implications for understanding Hirschsprung disease pathogenesis.
• The proposed methodology can be applied to other gene networks involved in common biological pathways.