To make diagnosing aHUS easier and improve patient care, the Japanese Society of Nephrology and the Japan Paediatrics Society (JSN/JPS) created criteria based on three main features: low platelet count (below 150,000/μL), microangiopathic haemolytic anaemia (shown by low haemoglobin, high lactate dehydrogenase, low haptoglobin, and fragmented red blood cells in a blood smear), and acute kidney failure (as per Kidney Disease: Improving Global Outcomes guidelines) [6]. The gene discussed is HP; the disease is kidney disorder.