Objective: To introduce the design and statistical methods of case-sibling control design and to analyze the published data.
Methods: Data from an association study between the coronary heart disease and methylenetetrahydrofolate reductase gene C677T polymorphism was analyzed by the sib transmission/disequibrium test (s-TDT) and the sibship disequilibrium (SDT) methods.
Results: Using s-TDT method, Z value was 0.27 with P > 0.05. The result of SDT method showed that chi-square was 0.31 with 1 df, P > 0.05. All results suggested that neither s-TDT nor SDT showed significant difference between the transmitted and untransmitted methylenetetrahydrofolate reductase gene C677T allele distributions.
Conclusion: Case-sibling control design might avoid population stratification by using siblings as controls thus might be used to test association and linkage between genes and disease.