A note on power approximations for the transmission/disequilibrium test

Area of Science:

• Genetics
• Biostatistics
• Disease Etiology

Background:

• The transmission/disequilibrium test (TDT) is widely used to identify the genetic basis of diseases.
• Accurate sample size and power calculations are crucial for designing effective TDT studies, especially under general genetic models.
• Existing power approximations for the TDT may lack precision.

Purpose of the Study:

• To develop a rigorous method for approximating the statistical power of the TDT.
• To provide accurate power calculations for TDT studies using family-based designs (single affected child or affected sib pairs).
• To evaluate and correct previously published TDT power approximations.

Main Methods:

• Developed a novel, rigorous method for power approximation in TDT analysis.
• Utilized simulation-based power calculations to validate the new method.
• Compared the derived power approximations with existing methods.

Main Results:

• The presented method provides precise power approximations for the TDT.
• Simulations confirm the accuracy of the new power calculation method.
• A previously published power approximation for the TDT was identified as erroneous.

Conclusions:

• The new method offers a reliable tool for researchers to determine sample size and power for TDT studies.
• Accurate power calculations are essential for the successful detection of genetic disease associations using the TDT.
• This work corrects a significant inaccuracy in the existing literature on TDT power analysis.