Nail-patella syndrome is a rare hereditary disorder that results in abnormalities of the kidneys, bones, joints, toenails, and fingernails.
Nail-patella syndrome is caused by a mutation of a gene that plays an important role in the development of limbs and kidneys.
Commonly, people who have this syndrome are missing one or both kneecaps (patellas), have an arm bone (radius) that is dislocated at the elbow, and have an abnormally shaped pelvic bone. Their fingernails and toenails are missing or poorly developed, with pitting and ridges. About 50% of people with this syndrome have blood or protein in their urine, which may prompt the doctor to order kidney function tests. Kidney failure eventually develops in about 30% of the people with affected kidneys by the time they are 50 or 60.
The diagnosis is suggested by the symptoms and confirmed by bone x-rays and a biopsy of kidney tissue. Genetic testing can be done if the diagnosis is still not clear.
There is no effective treatment for this syndrome.
Controlling blood pressure may slow the rate at which kidney function deteriorates. People who develop kidney failure need dialysis or a kidney transplant.
Genetic testing is usually offered to people who want to have children.
Last full review/revision December 2014 by David D. Sherry, MD; Frank Pessler, MD, PhD