Power calculations for the transmission/disequilibrium and affected sib pair tests using elementary probability...

Area of Science:

• Genetics
• Biostatistics
• Epidemiology

Background:

• Genetic association studies aim to link marker alleles with disease susceptibility.
• The Transmission/Disequilibrium Test (TDT) and Affected Sib Pair (ASP) test are common methods for detecting such associations.
• Accurate power and sample size calculations are crucial for efficient study design.

Purpose of the Study:

• To develop methods for calculating the statistical power of TDT and ASP studies.
• To provide methods for determining the required number of families for TDT and ASP studies.
• To assess the impact of study inclusion criteria on power and sample size.

Main Methods:

• Utilized a genetic model with a bi-allelic marker locus linked to a bi-allelic disease locus.
• Employed elementary probability calculations for power and sample size determination, avoiding complex approximations.
• Incorporated various study inclusion criteria, such as parental heterozygosity and minimum affected offspring.

Main Results:

• Presented straightforward methods for calculating power and sample size for TDT and ASP studies.
• Demonstrated that study inclusion criteria significantly influence the required sample size.
• The proposed methods offer simplicity and generality for study planning.

Conclusions:

• The developed methods provide a simple and general approach to estimate power and sample size for genetic association studies.
• These calculations are valuable for assessing study suitability and optimizing resource allocation.
• Consideration of specific inclusion criteria is essential for accurate sample size determination in TDT and ASP studies.