The Lancet mid-2016 had extensive coverage on the possible etiology (duckduckgo here: http://www.thelancet.com/journals/lancet/issue/vol387no10035/PIIS0140-6736(16)X0024-4 ) and a gene mutation was not one of them. It doesn't even make sense mechanistically, as the disease is linked to the HLA complex. Please provide scientific reference, otherwise I call bullshit.