Linkage analysis with cohort effects: an application to X-linkage

Area of Science:

• Genetics
• Psychiatry
• Statistical genetics

Background:

• Bipolar affective disorder (BPAD) is a complex psychiatric condition with a significant genetic component.
• Linkage analysis is a crucial tool for identifying genes associated with complex diseases.
• Traditional linkage analysis methods may not fully account for population-specific factors like cohort effects.

Purpose of the Study:

• To modify the LIPED program to incorporate cohort effects in linkage analysis for bipolar affective disorder.
• To investigate the potential linkage between bipolar affective disorder and X-chromosome markers.
• To assess the impact of age of onset distributions and transmission models on lod score results.

Main Methods:

• The LIPED program was adapted to include cohort effects.
• Linkage analysis was performed between bipolar affective disorder and deutan and protan markers on the X-chromosome.
• The sensitivity of lod score methods to age of onset distributions and transmission model parameters was evaluated.

Main Results:

• The modified LIPED program successfully incorporated cohort effects.
• Very significant positive lod scores were obtained, indicating linkage between bipolar affective disorder and both deutan and protan markers.
• Lod score results demonstrated sensitivity to the chosen age of onset distributions and transmission model parameters.

Conclusions:

• The modified LIPED program provides a more refined approach to linkage analysis by accounting for cohort effects.
• Significant evidence supports the localization of genes influencing bipolar affective disorder on the X-chromosome.
• Careful consideration of age of onset and transmission models is essential for accurate lod score analysis in genetic studies.