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TURNER SYNDROME ?>

TURNER SYNDROME

TURNER SYNDROME What is Turner syndrome? Turner syndrome is caused by a missing or incomplete X chromosome. People who have Turner syndrome develop as females. The genes affected are involved in growth and sexual development, which is why girls with the disorder are shorter than normal and have abnormal sexual characteristics. How do people get Turner syndrome?

Achondroplasia ?>

Achondroplasia

Achondroplasia Introduction Background Achondroplasia is a common, nonlethal form of chondrodysplasia. It is transmitted as an autosomal dominant trait with complete penetrance. De novo mutations cause 75-80% of cases. The mutation rate is estimated to be 0.000014 per gamete per generation. Cardinal features include short stature, rhizomelic shortening of the arms and legs, a disproportionately long trunk, trident hands, midfacial hypoplasia, prominent forehead (frontal bossing), thoracolumbar gibbus, true megalencephaly, and caudal narrowing of the interpedicular spaces. Pathophysiology

Achondrogenesis ?>

Achondrogenesis

Achondrogenesis Introduction Background Marco Fraccaro first described achondrogenesis in 1952.1 He used the term to describe a stillborn female with severe micromelia and marked histological cartilage changes. The term was later used to characterize the most severe forms of chondrodysplasia in humans, which were invariably lethal before or shortly after birth. By the 1970s, researchers concluded that achondrogenesis was a heterogeneous group of chondrodysplasias lethal to neonates; achondrogenesis type I (Fraccaro-Houston-Harris type) and type II (Langer-Saldino type) were distinguished on…

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