Autosomal dominant hemolytic uremic syndrome: variable phenotypes and transplant results

Autosomal dominant hemolytic uremic syndrome (ADHUS) is a rare disorder with a poor prognosis that was considered to present mainly in adults. Recurrent episodes of ADHUS were also thought to be uncommon. However, increasing reports suggest that children are often affected, that recurrent episodes may occur pretransplantation, and that post-transplant recurrences occur in about 50% of cases. We describe the occurrence of ADHUS in two unrelated families with different outcomes. It is apparent that there are several types of ADHUS (with and without serum complement abnormalities) and that there may be variable expression of the phenotype. There was variable penetration of HUS in four (possibly five) adults and two children in four generations of one kindred. There was also one definite unaffected carrier. Two patients had successful renal transplants without recurrences; the HUS recurred in a third patient soon after transplantation. In a second family, the father had three episodes of HUS at 18, 26 and 29 years of age; his son had one episode of HUS at 5 years of age. Both recovered completely. Evaluation of these patients, previous reports, and follow-up contacts of previous reports suggests that post-transplant recurrence of ADHUS is more common than previously reported and may not be prevented by prior nephrectomy of native kidneys.