Thanatophoric dysplasia is also known as lethal skeletal dysplasia, thanatophoric dwarfism, and lethal osteochondrodysplasia.

Thanatophoric dysplasia is a lethal skeletal dysplasia due to mutation of fibroblast growth factor receptor 3 gene (FGFR3).

Ultrasonographic findings

• long bones severely affected; micromelia is present; may have prominent bowing 
• ossification is normal and no evidence of fractures (differential of osteogenesis imperfecta)
• relatively normal shaped head; may be macrocephalic and may have midline hypoplasias
• small narrow thorax due to short ribs, which leads to hypoplastic lungs and abnormal cardiothoracic ratio
• heart, spine and abdomen are normal