cutis laxa

a group of disorders of the elastic fiber network in which the skin lacks elasticity and resilience and hangs in loose, pendulous folds. Hereditary forms are genetically heterogeneous and vary in severity and may be present at birth or develop soon afterwards; there is also a rare acquired from. The autosomal recessive form can be caused by several mutations: in either of two fibulin genes (FBLN4, locus: 11q13; FBLN5, locus: 14q32.1); in the ATP6V0A2 gene (locus: 12q24.3), which encodes a proton pump subunit; and in the PYCR1 gene (locus: 17q25.3), which encodes pyrroline-5-carboxylate reductase. It is associated with severe complications, including pulmonary and cardiovascular anomalies, diverticula of the urinary and gastrointestinal tracts, and multiple hernias. The autosomal dominant form is caused by mutation in either the elastin gene (ELN, locus: 7q11.2) or the fibulin 5 gene (FBLN5) and is essentially benign and of only cosmetic significance. The X-linked recessive form is occipital horn syndrome (q.v.). The acquired form, which is often preceded by mild fever, usually presents after puberty and sometimes not until middle age or later. Individuals with cutis laxa have a prematurely aged appearance, hooked nose with everted nostrils, long upper lip, everted lower eyelids, and sagging cheeks. Called also dermatochalasis, dermatomegaly, generalized elastolysis, and lax or loose skin.