The acceleration by a factor of about three is comparable with that of other mutations that accelerate ClC-7/Ostm1 gating by a factor between ~2.5 and >5 (Leisle et al., 2011; Ludwig et al., 2013) and is clearly stronger than the less-than-twofold acceleration by a recently identified human ClC-7 mutation causative for osteopetrosis (Barvencik et al., 2013). The gene discussed is OSTM1; the disease is osteopetrosis.