Thanatophoric dysplasia


What is thanatophoric dysplasia?

Thanatophoric dysplasia is a severe type of skeletal abnormality that causes extreme shortening of the limbs, a small ribcage with very short ribs, severely under-developed lungs, and abnormalities of the skull. Babies with thanatophoric dysplasia usually do not survive after birth because their lungs are too under-developed. There are two types of thanatophoic dysplasia (TD): type I and type II. There are several overlapping features that are seen in both TD type 1 and TD type 2, which include: a narrow ribcage, shortened ribs, a large head with distinctive facial features, poor muscle tone, shortened fingers and toes, and extra folds of skin along the limbs. Two major differentiators between TD type I and TD type 2 have to do with the shape of the femurs (thigh bones) and the shape of the skull. Babies with TD type I typically have bowing (curving) of the femurs and a large skull that has a relatively normal shape, while babies with TD type 2 typically have straight femurs and moderate-to-severe malformation of the skull called a cloverleaf deformity, ask the skull's shape resembles that of a three leaf clover when viewed from above.

The word "dysplasia" is Greek for "bad/difficult formation", referring the the abnormalities of the skeletal system. The word "thanatophoric" is Greek for "death-bearing" because most babies with TD are stillborn or die shortly after birth as a result of their severely under-developed lungs. With that said, there are a few individuals who have survived beyond the neonatal period with extensive medical assistance.

SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • • DATE UPDATED: 2016-12-10


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