Inherited Metabolic Diseases
Many inherited metabolic diseases have dermatological features. Characteristic findings include angiokeratomas, which are associated with several lysosomal storage disorders. Xanthomas occur in hyperlipidaemias, cerebrotendinous xanthomatosis, Niemann–Pick disease and glycogen storage disease type 1. Ichthiosis is found in steroid sulphatase deficiency, Sjögren–Larsson syndrome, Chanarin–Dorfman syndrome, Refsum disease, defects of cholesterol synthesis and some congenital disorders of glycosylation (CDGs). Cutis laxa is typical of other CDGs and Menkes disease. Photosensitivity occurs in the porphyrias, Hartnup disease and Smith–Lemli–Opitz syndrome. Hair abnormalities include alopecia (in biotinidase deficiency), hypertrichosis (in the mucopolysaccharidoses), trichorrhexis nodosa (in argininosuccinic aciduria) and pili torti (in Menkes disease).
Keywords inborn errors of metabolism, mucopolysaccharidoses, Fabry disease, angiokeratoma, multiple symmetrical lipomatosis, congenital disorders of glycosylation, fat pads, cutis laxa, trichorrhexis nodosa, pili torti