THE BONE IN TURNER SYNDROME

Abstract

Turner syndrome patients show growth retardation which leads to a final height considerably lower than the average. Short metacarpals, cubitus valgus, genu valgum, Madelung’s deformity, micrognatia and high arched palate are the result of the heterozy gous deletion of the SHOX gene due to the partial or total absence of one X chromosome. This haploinsuficiency of SHOX could also determine, together with other genes, the selective cortical bone deficiency of these girls, which is intensified during adolescence and adulthood because of the addition of trabecular hypomineralization as a consequence of estrogen deprivation. This defective mineralization leads to an increase in fracture risk. Growth hormone therapy improves final height whereas hormone replacement therapy is crucial for the acquisition and maintenance of bone mineral density.