title: Detection of imprinting effects for qualitative traits on X chromosome based on nuclear families.
abstract: Methods for detecting imprinting effects have been developed primarily for autosomal markers. However, no method is available in the literature to test for imprinting effects on X chromosome. Therefore, it is necessary to suggest methods for detecting such imprinting effects. In this article, the parental-asymmetry test on X chromosome (XPAT) is first developed to test for imprinting for qualitative traits in the presence of association, based on family trios each with both parents and their affected daughter. Then, we propose 1-XPAT to deal with parent-daughter pairs, each with one parent and his/her affected daughter. By simultaneously considering family trios and parent-daughter pairs, C-XPAT (the combined test statistic of XPAT and 1-XPAT) is constructed to test for imprinting. Further, we extend the proposed methods to accommodate complete (with both parents) and incomplete (with one parent) nuclear families having multiple daughters of which at least one is affected. Simulation results demonstrate that the proposed methods control the size well, irrespective of the inbreeding coefficient in females being zero or non-zero. By incorporating incomplete nuclear families, C-XPAT is more powerful than XPAT using only complete nuclear families. For practical use, these proposed methods are applied to analyse the rheumatoid arthritis data and Turner's syndrome data.
authors.affiliation: 1 State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Biostatistics, School of Public Health, Southern Medical University, China.
authors.forename: Ji-Yuan
authors.initials: JY
authors.lastname: Zhou
authors.affiliation: 2 Zhujiang Hospital, Southern Medical University, China.
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: You
authors.affiliation: 3 Department of Statistics and Actuarial Science, The University of Hong Kong, Hong Kong.
authors.forename: Ran
authors.initials: R
authors.lastname: Yang
authors.affiliation: 3 Department of Statistics and Actuarial Science, The University of Hong Kong, Hong Kong.
authors.forename: Wing Kam
authors.initials: WK
authors.lastname: Fung
mesh_terms: D000465:Algorithms; D001172:Arthritis, Rheumatoid / Q000235:genetics; D041321:Chromosomes, Human, X; D018392:Genomic Imprinting; D006801:Humans; D008957:Models, Genetic; D009010:Monte Carlo Method; D009679:Nuclear Family; D014424:Turner Syndrome / Q000235:genetics
keywords: Imprinting effects; Turner’s syndrome; X chromosome; nuclear family; qualitative trait