Led by Hediki Kato of Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine: a team of Japanese clinicians along with The Joint Committee for the Revision of Clinical Guides of Atypical Hemolytic Uremic Syndrome in Japan published a paper in 2016 setting out how aHUS should be diagnosed and treated in Japan.
The paper can be see here.
Japanese aHUS patients have had access to eculizumab following approval by Japanese health authorities in January 2015.
Japan was the first to identify a C5 mutation polymorphism in some patients which made PNH patients resistant to eculizumab rsulting in no blockage of the Complement cascade.
Of 345 Japanese patients with PNH who received eculizumab, 11 patients had a poor response. All 11 had a single missense C5 heterozygous mutation, c.2654G → A *, which predicts the polymorphism p.Arg885His.
The prevalence of this mutation among the patients with PNH (3.2%) was similar to that among healthy Japanese persons (3.5%). This polymorphism was also identified in a Han Chinese population.
A patient in Argentina of Asian ancestry who had a poor response had a very similar mutation, c.2653C → T, which predicts p.Arg885Cys.
see abstract here
Some Japanese patients therefore need access to an alternative complement inhibitor.
*a specific significant variant of a complement component
