What is Pycnodysostosis?

It is a rare genetic syndrome that presents with unique facial features, skeletal abnormalities and a hardening of the bones. It is a lysosomal storage disorder and often compared to osteoporosis. There is still a lot that isn’t known about the disease, in terms of its symptoms, and symptoms may vary widely across affected individuals.

The syndrome has currently been reported in 200 people worldwide, but it is possible that the syndrome is under diagnosed.

What gene changes cause Pycnodysostosis?

Mutations in the CTSK gene cause the syndrome.

It is inherited in an autosomal recessive pattern. Some affected individuals have parents related by blood, which increases the risk of having a syndrome inherited in an autosomal recessive pattern.

What are the main symptoms of Pycnodysostosis?

The earliest identified symptoms of the syndrome may include a larger skull than normal. This is caused by the delayed fusing together of the joints of an infant's skull known as sutures.

Unique facial features of the syndrome include a prominent forehead, a pointed nose, a high arched palate, prominent eyes that are blue and a small jaw.

Dental issues are also common. These might include the delayed eruption of baby and permanent teeth. In some instances teeth fail to develop at all.

Bone anomalies include a malformed collarbone and a breakdown of the bone in the tips of fingers and toes. Fingers may also be smaller than normal with missing fingernails. A hardening of the bones is common with the syndrome. This in turn causes fragile bones, leaving affected individuals more susceptible to fractures. These fractures might be caused by injury or appear without being injured.

Respiratory and sleep issues are also possible symptoms. These are often caused by a malformation of the chest triggered by the syndrome.
A short stature and shorter limbs are also associated with the condition.

How does someone get tested for Pycnodysostosis?

The initial testing for Pycnodysostosis can begin with facial analysis screening, through the FDNA Telehealth telegenetics platform, which can identify the key markers of the syndrome and outline the need for further testing. A consultation with a genetic counselor and then a geneticist will follow.

Based on this clinical consultation with a geneticist, the different options for genetic testing will be shared and consent will be sought for further testing

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