Infantile Systemic Hyalinosis: report of three unrelated Brazilian children and review of the literature.

Infantile Systemic Hyalinosis (ISH) is an autosomal recessive disorder characterized by diffuse hyaline deposits in the skin, gastrointestinal tract, muscles and glands. Recently, mutations in the capillary morphogenesis gene-2 (CMG-2), a transmembrane protein with important roles in cell-cell adhesion and cell-extracellular matrix interactions, have been shown to cause ISH. We report on three unrelated Brazilian children presenting in the first days of life with a limited range of joint movements, progressing to painful joint contractures. Additional findings included skin hyperpigmentation over small joints, enlargement of major joints, rigid vertebral spine, thickened skin, facial papuloerythematous rash, and cervical, dorsal and perianal nodules. Skin biopsy performed in all three patients showed diffuse deposits of hyaline material, confirming the diagnosis of ISH.