The ossification of the calvaria and phalanges is different from rest of the skeleton and Suoranta et al. (2012) proposed that the bone changes in EPM1 patients, most importantly, the thickening of the skull and arachnodactyly, could be mediated through the lack of cathepsin K inhibition, caused by reduced CSTB in cells and this would lead to altered osteoclast function. The gene discussed is CSTB; the disease is congenital contractural arachnodactyly.