Dean et al found increased expression of integrin a-1, a-2 subunits. This increased expression remained when the fibroblasts were transferred to matrix. These results pointed to a primary defect of integrins or integrin regulators.
Recently, Herrmann et al showed that mice with targeted disruption of the fatty acid transport protein 4 gene (Fatp4) show clear signs of RD. They suggested that a defective fatty acid transport protein influenced the arrangement of lipids in the epidermis and led to these skin defects.
Clair and others suggested that RD is either a primary or a secondary laminopathy caused by mutation in the lamin A and С (LMNA) gene, leading to the production and accumulation of truncated prelamin A, and mutations in zinc me tallopro teinase. levitra plus
RD should be distinguished from other forms of lethal congenital contracture syndromes such as Pena-Shokeir syndrome and Neu-Laxova syndrome. These diseases are caused by a primary defect of the central nervous system, and do not present tautness of the skin.
RD can be confused with severe disorders which present rigid skin such as sclerema neonatrum and scleredema. In sclerema neonatrum, histological features are characterized by subcutaneous fibrosis, fat necrosis, and crystallization of fat contents. In scleredema, hardening of skin is not extensive at birth and histological features are not associated with abnormality of elastic fibers.
Stiff skin syndrome should be differentiated from RD. Stiff skin syndrome is characterized by hardening of skin mainly on the buttocks, thighs, and lower legs. The involved area shows mild hypertrichosis. In contrast to RD, where the dermis usually thinned out, histological features show excessive production of collagen by fibroblasts, and deposition of hyaline materials or mucopolysaccharide. canadian pharmacy generic viagra
The ichthyosis congenita of harlequin fetus and lamellar ichthyosis need to be excluded. In harlequin fetus, there is marked hyperkeratosis of the skin with papillomatosis and non- destructive plugging of hair follicles and sweat ducts. Lamellar ichthyosis is manifested by a collodion baby phenotype and is characterized by erythema, generalized scales of plate-like type of ectropion, and in contrast to RD, skeletal anomaly is not associated.