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Thanatophoric Dysplasia

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What is thanatophoric dysplasia (thanatophoric dwarfism)?

Thanatophoric dysplasia is a rare genetic condition that affects bone development. It’s a type of skeletal dysplasia, a group of conditions that affect bone and cartilage growth. Another name for thanatophoric dysplasia is thanatophoric dwarfism.

There are two types of thanatophoric dysplasia:

  • Type I (one): Children have curved thigh bones and flat spinal bones.
  • Type II (two): Children have straight thigh bones and a unique skull shape called cloverleaf skull.

Thanatophoric dysplasia is a severe, life-threatening condition. Because it causes a very narrow chest and ribcage, babies born with thanatophoric dysplasia have difficulty breathing on their own. Many infants with thanatophoric dysplasia die shortly after birth.

Thanks to technological advances in medicine, some babies with the condition may survive past infancy. All children with thanatophoric dysplasia have long-term medical needs, including dependency on a ventilator for breathing and significant changes in neurologic function and development.

What causes thanatophoric dysplasia?

Thanatophoric dysplasia occurs because of a gene change (mutation) in the FGFR3 gene. This gene is responsible for making a protein that supports bone and brain tissue development.

The gene mutation that causes thanatophoric dysplasia happens due to random changes in the FGFR3 gene. It isn’t inherited, and the condition doesn’t tend to run in families.

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