Thanatophoric dysplasia

Thanatophoric dysplasia (TD) is a rare, severe skeletal condition. The condition is congenital meaning a baby is born with the condition. TD results from a change in the baby’s DNA or genes (genetic). A baby born with TD will have underdeveloped bones and lungs. This condition is typically diagnosed during pregnancy during an ultrasound exam. Further genetic tests of the baby can determine the genetic mutation.

Symptoms of TD may include very short limbs, extra folds of skin, large head and forehead, shortened ribs, and underdeveloped lungs. There are two types of this condition. Thanatophoric dysplasia type 1 (TD1) is the more common type. With TD1, the leg bones (femurs) are typically curved and the baby has a normal shaped skull. Thanatophoric dysplasia type 2 (TD2) is less common. With TD2, the baby has straight leg bones, but a cloverleaf-shaped skull. Sadly, babies with both types of this condition are stillborn or pass away a short time after birth. There have been reported cases where the baby has lived slightly longer with the help of medical intervention.

The cause of both types of TD is an error (mutation) in a gene located on chromosome 4. The gene, named fibroblast growth factor receptor 3 (FGFR3), is responsible for bone and brain tissue development. When altered, the gene cannot pass along the information to make bones of the right length. This condition arises by random chance (de novo), meaning that the parents do not have the error in their own gene. Therefore, the risk of the couple having another child with this condition is low.

Unfortunately, there is no cure for TD at this time. This is a very serious condition and parents often struggle with the emotional tolls of facing this diagnosis. Therefore, if your baby has been diagnosed with thanatophoric dysplasia, it is helpful to speak with a doctor, genetic counselor, or therapist to gain information about the condition and support.