[Secondary osteoporosisn in boys with Alagille syndrome. Case report].

Alagille syndrome is a multiorgan disorder, which especially manifests itself with cholestasis, characteristic facial features, circulatory systems defects, defects of the front segment of the eye, dysplastic changes in bones and kidneys and impaired angiogenesis.The disease is caused by Jagged 1 gene mutation (JAG, 20p12 chromosome) which encodes ligand for Notch receptor. JAG/ Notch signaling pathway plays important evolutionary role in cell differentiation in organogenesis process . JAG1 expression in numerous tissues leads to multiorganic manifestation. Jagged 1 expression is substantially important for skeleton growth and bone cells activity. Its malfunction may lead to spine and long bones abnormalities, neoplastic changes and osteoporosis. In this case report authors present clinical (long bone fractures) and biochemical manifestations and densitometric abnormalities ( decrease of bone mineral density) in 10 years old boy with Alagille syndrome. Densitometry is suggested to be a good method in early detection of mineralization disturbances in chronic cholestasis and permanent monitoring of changes in bone structure is also very important.