Thanatophoric dysplasia type 1

Definition

A form of thanatophoric dysplasia characterized by prenatal onset of growth deficiency of the limbs of less than 5%, bowed femurs (like a telephone receiver), shortened ribs, and platyspondyly. Fetal MRI can identify temporal lobe abnormalities and a narrow foramen magnum. Postnatally, distinctive facial features include macrocephaly, large anterior fontanel, frontal bossing, midface hypoplasia, proptosis, and low nasal bridge. Neonates usually die shortly after birth due to respiratory insufficiency and/or spinal cord/brain stem compression.