Vignette #3: Atypical Hemolytic Uremic Syndrome (aHUS)
A 13-month-old male from the Dominican Republic with newly diagnosed
high-risk neuroblastoma developed severe hypertension, thrombocytopenia,
and acute renal failure after receiving one dose of topotecan and
cyclophosphamide as part of induction chemotherapy. Given normal
ADAMTS13 function and worsening hemolysis unresponsive to rasburicase
and steroids, there was heightened concern for aHUS. Weekly eculizumab
infusions were initiated with improvement in the aHUS. Predisposition
gene testing revealed a heterozygous VUS in complement factor H (CFH)
that has been reported once prior in association with increased
susceptibility to HUS, and was predicted by in silico models to
be pathogenic9. His aHUS remains in remission.