A rare sporadic case of C3 gene mutation in 5-month-old baby girl with atypical hemolytic uremic syndrome, with good prognosis

• Main Authors: Abdullah A Baothman, Hani Almalki, Mohammed Almaghrabi
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2018-01-01
• Series: Journal of Applied Hematology
• Subjects: Atypical hemolytic uremic syndrome; eculizumab; microangiopathy
• Online Access: http://www.jahjournal.org/article.asp?issn=1658-5127;year=2018;volume=9;issue=3;spage=104;epage=107;aulast=Baothman

Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy representing <10% of HUS cases, characterized by hemolytic anemia, thrombocytopenia, and renal failure. A 5-month-old baby girl, the daughter of Saudi nonconsanguineous parents, presented with fever, vomiting, and watery diarrhea when she was admitted as a case of gastroenteritis. The laboratory results showed high urea (10.2 mmol/L) and creatinine (134 μmol/L) as well as low hemoglobin (4.5 g/dL) and a low platelet count (81 × 109/L) with a normal coagulation profile. Blood, urine, and stool cultures were all negative for bacterial growth. Despite the lack of strong indicators of aHUS, the patient received 4 weekly cycles of eculizumab in the induction phase (300 mg/m2/dose intravenously over 2 h) based on the clinical emergence diagnosis. She showed dramatic improvements in clinical and laboratory parameters and was taken off peritoneal dialysis. Molecular tests confirmed our clinical diagnosis and revealed a rare heterozygous missense variant of the C3 gene, c.3343G>A, p.(Asp1115Asn). The early recognition and administration of eculizumab are a lifesaving measure. C3 gene mutations are an autosomal dominant inherited pattern, with 50% risk of inheriting this mutation. Therefore, genetic counseling and family member testing are recommended.