Nail Patella Syndrome
Nail patella syndrome (NPS) is a disease that affects the organs of the body with an ectodermal and mesoderm origin. Ectodermal organs include the beginning of tissues that cover the surfaces of the body. Mesoderm includes multiple tissues in the body as well as muscle, bones, connective tissue, and the middle layer of skin. This condition is often referred to as hereditary osteo-onychodysplasia (HOOD).
There are three known causes of this condition. One of the causes of this disorder is an autosomal dominant hereditary disease. These are hereditary diseases that are passed on through family members from one generation to another. It often follows a specific pattern of inheritance.
The second known cause of the disorder is a genetic abnormality. It is not known for sure, but it is believed the abnormality affects the connective tissue’s metabolism due to structural defects in collagen. The third known cause also involves collagen. It is caused from the abnormal collagen deposition.
Symptoms and Complications
Symptoms and complications of NPS can be unique to each patient. The most common place the symptoms appear is the fingers and fingernails. The most common symptom is abnormal or absent fingernails. Often, multiple fingers are affected; however, the toes are less likely to exhibit any symptoms. The nails, especially those on the index fingers and thumbs, often appear concave, contain splits or ridges, and discoloration.
The bones and joints are often affected by the condition as well. The kneecaps are the second most common area affected by the rare disorder. The kneecaps are either deformed or missing. They often easily dislocate and have a square appearance. The surrounding joints, bones, tendons, and ligaments can also be victims of deformities. This makes if very difficult for people with the condition to walk. The hip bones often contain bone spurs, which usually cause no symptoms.
The kidneys are often affected by the condition. Kidney failure is a concern among patients with this condition, and an early diagnosis is important to prolong the use of the kidneys. Early symptoms of kidney failure include blood in the urine.
The skin can also be affected by this rare disorder. The skin on the hands is often excessively wrinkled or loose, while the skin on the joints is unusually tight. This can cause extreme difficulty flexing the joints of the fingers.
Eye problems are a more serious complication of the condition. Glaucoma is a common concern among NPS patients. If left untreated, optic nerve damage and blindness can occur.
Skeletal problems are also common. Many patients experience bent or deformed fingers. The shoulder blades are often poorly developed, limiting movement. Unusual neck bones and scoliosis are often associated with nail patella syndrome. Clubbed feet and hip dislocations often occur as well.
Treatment of the condition usually involves treating the individual symptoms or complications. There is no cure for the disorder. Surgical procedures may be needed to repair the damages that can occur to the eyes, bones, joints, and kidneys. If complications with the kidneys arise, that is treated with dialysis or a transplant.
“Nail-Patella Syndrome" April 21, 2009 EMedicine
“Nail-Patella Syndrome" University of Michigan
“What is Nail-Patella Syndrome?" 2008 Genetics Home Reference