Background Familial aggregation of Ankylosing spondylitis (AS) has been frequently documented. Disease susceptibility has been testified to be clearly attributable to genetic factors, but the mode of inheritance in AS remains poorly understood within a limited number of studies.
Objectives The objective of this study was to determine the mode of inheritance that best fits the observed transmission pattern of AS among Chinese Han families.
Methods Nine families with five or more AS patients diagnosed with 1984 modified New York criteria were recruited from the third affiliated hospital of Sun Yat-sen University. By using the Statistical Analysis for Genetic Epidemiology (S.A.G.E.) program, we performed complex segregation analysis for a binary trait in regressive multivariate logistic models to determine the mode of inheritance of AS. The inheritance models, including sporadic, major gene, environmental, general and other 9 models, were compared by likelihood ratio tests and Akaike's Information Criterion.
Results This research included 9 Chinese Han family with a total number of 315 members. There were totally 113 AS patients, including 43 male patients and 31 females. Complex segregation analysis revealed Mendelian dominate inheritance mode fitted best in five AS families, while a non-Mendelian model called Tau AB free model best explained the mode of inheritance in these AS families.
Conclusions This study further provided evidence in support of Mendelian dominant mode in AS, and firstly discovered a non-Mendelian mode called tau AB free inheritance mode in AS Chinese Han pedigrees, implying AS could be a polygenetic or multifactoral disease.
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Acknowledgements We thank Dr. Rao Shaoqi and Dr.Zuo Xiaoyu for the assistance of performing the software.
Disclosure of Interest None declared