Four and two male sibs of two separate families who had biopsy-proven
membranoproliferative glomerulonephritis (MPGN) are presented. In the
first family four sibs of the first-degree consanguineous marriage sho
wed the clinical picture of nephrotic syndrome without hypocomplementa
emia at initial laboratory findings. In the second family two affected
sibs showed nephrotic and nephritic syndromes on admission. Family in
vestigations showed normal serum complement, immunoglobulins, T-cell s
ubsets, urine analysis, and serum biochemistry. HLA typing in the two
families revealed a common antigen HLA A2 in all affected sibs. Some o
ther reports give suggestive evidence of MPGN in siblings but this is
the first report that showed the occurrence of MPGN in four sibs. Our
data strengthened the concept that genetic factors are involved in the
development of MPGN but additional immunogenetic studies will shed li
ght on the genetic aspects of the disease.