Infantile systemic hyalinosis: Report of two severe cases from Saudi Arabia and review of the literature.

Infantile systemic hyalinosis (ISH) (OMIM 228600) is a rare fatal autosomal recessive disorder characterized by extensive deposition of hyaline material in many tissues. Consanguinity has been recorded in many cases. Herein we present two new Saudi cases with review of the literature. Our first proband was a 9 month-old male who was the first baby for parents descended from a closed consanguineous pedigree. The second proband was a 13 month-old male who was the first baby for consanguineous parents (3(rd) C). Both cases presented with bilateral painful limited limb movement with joints contractures, low birth weight (< P5), severe generalized stiff skin, hyper-pigmented skin over bony prominences, fleshy perianal masses and gingival hypertrophy. The first child died at 18(th) month as a result of recurrent chest infections. The second proband showed a severe progressive course of joint contractures, and died at 19(th) month because of failure to thrive and recurrent infections. Although the clinical features of ISH are characteristic, the disease is under/miss diagnosed. The role of consanguinity needed to be highlighted to the community. Careful clinical examination and molecular diagnosis will be helpful for genetic counseling, prenatal diagnosis and early treatment.