A genomic imprinting test for ordinal traits in pedigree data

Area of Science:

• Genetics
• Statistical Genetics
• Human Disease Inheritance

Background:

• Genomic imprinting causes differential gene function from maternal or paternal alleles, impacting complex human disorders.
• Existing statistical methods for parent-of-origin effects are limited to binary or continuous traits, not ordinal scales common in many diseases.
• Imprinting's role in the genetic basis of ordinally scaled traits remains largely unexplored.

Purpose of the Study:

• To extend a latent variable model to incorporate parent-of-origin information for imprinting analysis.
• To develop a novel score statistic for testing imprinting effects in genetic linkage analysis of ordinal traits.
• To investigate the genetic basis of alcoholism, considering imprinting and parent-of-origin effects.

Main Methods:

• Developed an extended latent variable model incorporating parent-of-origin effects.
• Created a computationally efficient score statistic for imprinting linkage analysis in pedigrees.
• Validated the test statistic through simulations and applied it to real-world genetic data.

Main Results:

• The novel statistical method successfully detected imprinting effects in linkage analysis for ordinal traits.
• A significant novel imprinting locus was identified on chromosome 18 associated with alcoholism.
• Two additional loci on chromosomes 3 and 4 showed significant linkage with alcoholism.

Conclusions:

• The developed statistical framework effectively analyzes imprinting in complex diseases measured on ordinal scales.
• The findings highlight the importance of considering genomic imprinting in the genetic architecture of alcoholism.
• The study provides a valuable tool for dissecting parent-of-origin effects in a broader range of human diseases.