ANALYSIS OF SEGREGATION AND INHERITANCE OF HLA CLASS-I ALLELES IN FAMILIES WITH HLA-B27 POSITIVE PATIENT SUFFERING FROM ANKYLOSING-SPONDYLITIS

The segregation and inheritance of B27-bearing haplotypes in 223 famil ies with at least one B27+ patient suffering from ankylosing spondylit is has been analysed. Familial segregation of B27+ haplotypes has been followed in 103 families undergoing bone-marrow or kidney transplanta tion (control group CI). The statistical significance (p<0.05) was fou nd when ratio between B27+ males and females in AS group was compared with same ratio in C-I group. Parental inheritance of HLA-B27 has also been analysed in AS families and 488 families undergoing paternity te sting (control group C-2). In both groups maternal and paternal inheri tance of B27 was followed separately. The total number of sibs in RS g roup was 457; the paternal inheritance was followed in 284 and materna l in 173 siblings. The most striking result was ratio of B27+ and B27- sons (2.4:1) in whom B27 is inherited from mother. This was highly st atistically significant (p<0.001) when compared with the same mode of inheritance in the control group. Possible explanations of-his unusual inheritance are higher affinity between oocyte B27+ and y-sperm cell or preferable implantation of male B27+ zygote versus female B27+ zygo te in B27+ mother.