Do genetic factors play a role in Berger's disease?

The epidemiology of Berger's disease is poorly defined. We know that the disease occurs worldwide and that there may be an increased occurrence in certain ethnic groups. Whether secondary mesangial IgA deposits should be considered part of the same disease process is unknown. The association of certain HLA antigens with the occurrence of Berger's disease has been demonstrated by several groups. The multiple occurrence of Berger's disease or of Berger's disease and Henoch-Schönlein purpura in the same family has been reported. The preliminary results of a French collaborative study show 43 such families. However, these facts do not demonstrate a familial clustering since the multiple occurrence of cases in a family may occur by chance. The study of affected siblings (sib pair method) from different families may be used nevertheless, in order to understand the possible inheritance of the disease. Previously reported data on HLA haplotypes of affected siblings are combined with unpublished cases. There is an excess of HLA-identical siblings but it is possible that there might have been some bias towards publishing HLA-identical pairs. Further systematic studies on a large number of HLA-typed affected sibling pairs are needed before concluding a linkage between HLA and the disease.