Juvenile hyaline fibromatosis (JHF) is characterized by papulonodular skin lesions, soft tissue masses, gingival hypertrophy, and flexion contractures of the large joints. Age of onset varies from infancy to early childhood. Mental development and life expectancy are normal. There is no apparent ethnic predisposition, as the 40-50 reported cases come from various populations. JHF is transmitted as an autosomal recessive trait. The gene for JHF was mapped to chromosome 4q21 and the causative gene was recently identified as capillary morphogenesis protein 2 (CMG2), which causes both JHF and the related condition infantile systemic hyalinosis (ISH). CMG2 is a transmembrane protein that is induced during capillary morphogenesis and that binds laminin and collagen IV via a von Willebrand A (vWA) domain suggesting that perturbation of basement membrane matrix assembly maybe the cause of the characteristic perivascular hyaline deposition seen in these conditions. Typical diagnostic criteria are multiple hyaline subcutaneous fibroma, filamentous tumors of the skin, gingival fibromatosis, muscle contractures of the extremities and multiple osteolytic bone destructions. There is currently no causal treatment available for JHF. Surgical excision of the dermal tumors is indicated for functional and esthetic improvement. Complete excision should be performed in the early phase of tumor development.
Last update: March 2005