Skeletal Dysplasias

The most common causes of dwarfism are the skeletal dysplasias, including: achondroplasia, dias-trophic dysplasia (diastrophic dwarfism), and spondyloepiphyseal dysplasias (SED).

Achondroplasia This is a form of short-limb dwarfism caused by a single autosomal dominant gene, which means that a spontaneous mutation in the gene can produce the condition, or a child can inherit the gene from a parent with achondroplasia. Children with achondroplasia have a relatively long trunk and shorter upper arms and legs, together with a large head, prominent forehead, pronounced abdomen, bowed legs, short feet and fingers, and limited flexibility of the elbows and hips.

Diastrophic dysplasia This is another form of short-limb dwarfism, which causes shortened forearms and calves of the arms and legs. Significant bowing of the legs further reduces the child's height. Other characteristics often include club-foot, broad hands with low-set thumbs that turn out, cysts on the upper ear that progress to swelling and thickening of the ears. Although the size of the head appears normal at birth, the face usually develops a long, full appearance with a

0 0

Post a comment