Thanatophoric dwarfism results from a sporadic defect in the fibroblast growth factor-3 gene, a transmembrane regulator. The disease is lethal, usually shortly after birth due to respiratory failure. The incidence is approximately 1 in 10,000 births and is the most common lethal bone dysplasia.
There are several characteristic radiographic findings, illustrated above. First, the disease is rhizomelic, with relative shortening of the humeri and femora. The femora are curved and in a classic "telephone-receiver" configuration. The ribs are short and horizontal and the thoracic cage is hypoplastic. The iliac wings are small and squared. Also, there is generalized flattening of the vertebral bodies. Also characteristic is the protuberant abdomen.
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Lemyre E, Azouz EM, Teebi AS, Glanc P, Chen
MF. Bone dysplasia series. Achondroplasia, hypochondroplasia and
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