Familial nephrotic syndrome and focal segmental glomerulosclerosis.

Three of five siblings developed a steroid-resistant nephrotic syndrome with focal segmental glomerulosclerosis within a four-month period. Two of the siblings with nephrotic syndrome (Patients 1 and 2) also have sickle cell anemia; the third (Patient 3) carries the thalassemia trait. The dizygotic twin brother of Patient 2 has sickle cell anemia, but does not have the nephrotic syndrome. The nephrotic syndrome of patient 1 was resistant to corticosteroid and cyclophosphamide therapy and she developed severe renal failure 14 months after onset. The nephrotic syndrome of Patients 2 and 3 was steroid resistant but was partially responsive to cyclophosphamide therapy. They have persistent proteinuria with mild elevation of serum creatinine concentration and hypertension 5 1/2 years after diagnosis. In this family, the nephrotic syndrome appeared unrelated to the specific hemoglobinopathy, HLA type or mixed lymphocyte culture responsiveness despite the similarity of the renal disease.