What is pachyonychia congenita?
Pachyonychia congenita (PC) is a very rare genetic disorder that affects the skin and nails. Most people have thickened nails and calluses on the bottom of the feet. Painful calluses on the soles can make walking difficult. Because of the pain, some people rely on a cane, crutches, or a wheelchair to help with walking.
Who gets pachyonychia congenita?
PC is very rare. The symptoms usually begin at birth or early in life. It affects people of both sexes and all racial and ethnic groups.
People who have pachyonychia congenita have a mutation (change) in one of their genes. In some cases, PC is passed from a parent to a child, while in others, there is no family history of the disorder.
What are the types of pachyonychia congenita?
There are five types of PC. The type depends on which gene mutates, or changes.
What are the symptoms of pachyonychia congenita?
The symptoms of PC can vary widely, even among people with the same type or in the same family.
The most common symptoms of PC include:
- Painful calluses and blisters on the bottom of the feet. In some cases, the calluses itch. Calluses and blisters may also form on the palms of the hands.
- Thickened nails. Most people with PC have some nails that thicken.
- Cysts of various types.
- Bumps around hairs at places where skin rubs together, such as the waist, hips, knees, and elbows. They are most common in children and lessen after the teenage years.
- White film on the tongue and inside the cheeks.
Other symptoms of PC include:
- Sores at the corners of the mouth.
- Teeth at or before birth.
- White film on the throat, resulting in a hoarse voice.
- Intense pain on first bite (“first bite syndrome”). The pain is near the jaw or ears and lasts 15–25 seconds when a person begins to eat or swallow. This is more common in younger children and may cause feeding difficulties for some infants. It typically goes away during the teenage years.
What causes pachyonychia congenita?
Pachyonychia congenita is caused by mutations in genes that affect proteins in skin, nails, and hair.