DR2/DQwl Inheritance and haplotype sharing in affected siblings from multiple sclergis families

Although the human leukocyte antigen DFWDQwl allele has been associated with multiple sclerosis, studies of DRZ/DQwl inheritance in multiple sclerosis multiplex families have yielded conflicting results. We examined this question in “highincidence” families, defined as families with more than 50% of siblings affected. DR2/ DQwl allele frequencies were significantly increased, particularly in mothers and affected siblings ( p < 0.0001). The transmission of DR2IDQwl from both parents was more frequent in affected offspring ( p = 0.005). While evidence for segregation of disease with a particular parental allele was lacking in most families, the frequency of haplotype sharing was higher in affected sib pairs ( p < 0.01).