Abstract

Family studies are widely used for research into genetic and environmental influences on human traits. In this paper, we establish statistical methodology for the estimation of a new measure of sib similarity with respect to dichotomous traits measured on each member of within family sib-pair. We call this parameter "excess risk." For inference problems involving a single sample, we construct a large sample confidence interval on the concerned parameter. It has long been suspected that consanguinity is a risk factor for many genetic defects. Therefore, we establish a procedure to test the significance of the difference between excess risk parameters in a sample of consanguineous marriages and another sample of non-consanguineous marriages. We apply the methodology to data from a hospital-based congenital heart defects registry in Saudi Arabia, a population in which consanguinity is quite common.

Recommended Citation

Shoukri, Mohamed M.; Donner, Allan; Dessouky, Nadia Abdalla; Subhani, Shazia; Al-Joufan, Mansour; Al-Omrani, Ahmed; Al-Mohanna, Futwan; and Al Halees, Zohair Y. (2010) "Estimation of Modified Concordance Ratio in Sib-Pairs: Effect of Consanguinity on the Risk of Congenital Heart Diseases," The International Journal of Biostatistics: Vol. 6 : Iss. 1, Article 3.
DOI: 10.2202/1557-4679.1216
Available at: http://www.bepress.com/ijb/vol6/iss1/3