Dyggve-Melchior-Clausen (DMC) syndrome
is a rare, progressive genetic condition characterized by abnormal skeletal development, microcephaly, and intellectual disability. Only about 100 cases have been reported to date. Skeletal abnormalities may include a barrel-shaped chest with a short truck, partial dislocation of the hips, knock knees, bowlegs, and decreased joint mobility. A small number of affected individuals experience instability in the upper neck vertebrae that can lead to spinal cord compression, weakness and paralysis. Normally, there is growth deficiency resulting in short stature. DMC is caused by mutations in the DYM gene and is inherited in an autosomal recessive manner. Some researchers have described an X-linked pattern of inheritance, which has not been confirmed to date. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.