A congenital or acquired condition characterized by deficient elastic fibers of the skin, which may hang in folds; vascular anomalies may be present; inheritance is either autosomal dominant or recessive, the latter sometimes in association with pulmonary emphysema and diverticula of the alimentary tract or bladder. The dominant form is caused by mutation in the elastin gene (ELN) on 7q. There is also an X-linked form that is due to mutation in the Menkes gene (MNK), encoding copper-transporting ATPase on Xq. SYN: cutis laxa, generalized elastolysis, loose skin. [dermato- + G. chalasis, a loosening]