Given his presentation of thrombotic microangiopathy (TMA), along with laboratory results significant for low haptoglobin, platelets, hemoglobin, C3, C4, CH50, and normal ADAMTS13 levels, with no diarrhea and negative STEC polymerase chain reaction in stool, aHUS diagnosis was established with strong clinical suspicion, and immediate initiation of treatment was advised. Here, C4A is linked to Genetic thrombotic microangiopathy.