Thanatophoric Dysplasia


  • 1 in 10,000 births.
  • Most common lethal skeletal dysplasia.

Ultrasound diagnosis:

  • Severe shortening of the limbs, narrow thorax, normal trunk length and large head with prominent forehead.
  • There are 2 types of thanatophoric dysplasia:
    • Type I (more common): sporadic, the femurs are curved (telephone receiver).
    • Type II (rare): sporadic, the femurs are straight but the skull is cloverleaf-shaped.


  • Detailed ultrasound examination.
  • Thanatophoric dysplasia is due to a mutation in the FGFR3 gene. The diagnosis can be made by invasive testing or cfDNA analysis of maternal blood.

Follow up:

  • If pregnancy continues, follow-up should be standard.


  • Standard obstetric care and delivery.
  • Pregnacies are often complicated by polyhydramnios, prematurity, malpresentation and cephalopelvic dysproporion. The presence of the cloverleaf deformity and hydrocephalus may require cephalocentesis and assisted delivery.


  • The condition is lethal due to severe pulmonary hypoplasia.


  • No increased risk.”

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