What is aHUS?
Haemolytic uraemic syndrome (HUS) comprises the triad of microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury. Approximately 90% of cases are caused by Shiga-toxin producing bacteria, such as Escherichia coli O1:57 and are called STEC-HUS. The remainder of cases are called atypical haemolytic uraemic syndrome (aHUS), this consists of primary complement mediated aHUS and secondary forms of aHUS
Complement mediated aHUS is an ultra-rare disease, incidence is estimated at 0.4 per million per year. It typically presents in childhood and young adulthood but can present throughout adulthood. At least half of patients with aHUS are known to have an abnormality of regulation of the alternative pathway of complement that leads to dysregulation of complement at the endothelial surface.