Nail-patella syndrome, also known as hereditary onycho-osteodysplasia or Turner-Kieser syndrome, is a rare genetic disorder that primarily affects the development of nails, bones, and joints. This condition is caused by mutations in the LMX1B gene, which is responsible for the formation of various body structures during embryonic development. Nail-patella syndrome is inherited in an autosomal dominant pattern, meaning that an affected individual has a 50% chance of passing the condition on to each of their children.
Nails: One of the hallmark features of nail-patella syndrome is abnormal nail development. Individuals with this condition often have underdeveloped or absent nails, a condition known as hypoplastic or absent patella. The nails may be small, discolored, pitted, ridged, or spoon-shaped. In some cases, the nails may also be easily breakable or brittle.
Skeletal abnormalities: Nail-patella syndrome can also affect the development of bones and joints throughout the body. The most commonly affected areas include the elbows, knees, and hips. Individuals with this condition may have underdeveloped or absent kneecaps, a condition called patellar aplasia or hypoplasia. This can lead to knee pain, instability, and difficulty with walking or running. Additionally, some individuals may have limited range of motion in the elbows, hip abnormalities, or scoliosis (curvature of the spine).
Eye abnormalities: Some individuals with nail-patella syndrome may also have eye abnormalities. These can include glaucoma, a condition characterized by increased pressure within the eye that can lead to vision loss if left untreated. Other eye abnormalities that may be present include cataracts, myopia (nearsightedness), and strabismus (crossed or misaligned eyes).
Kidney problems: Nail-patella syndrome can also affect the kidneys. Approximately 30-50% of individuals with this condition develop kidney abnormalities, which can range from mild to severe. These abnormalities may include proteinuria (presence of excess protein in the urine), hematuria (blood in the urine), or even kidney failure. Regular monitoring of kidney function is essential for individuals with nail-patella syndrome.
Other features: In addition to the primary symptoms mentioned above, nail-patella syndrome may also present with other features. These can include hearing loss, dental abnormalities (such as small or missing teeth), and a higher risk of developing high blood pressure. Some individuals may also have hypermobile joints, meaning their joints can move beyond the normal range of motion.
It is important to note that the severity and specific combination of symptoms can vary widely among individuals with nail-patella syndrome. Some individuals may have mild symptoms that do not significantly impact their daily lives, while others may experience more severe complications that require medical intervention.
If you suspect that you or your child may have nail-patella syndrome, it is important to consult with a healthcare professional for a proper diagnosis and appropriate management. Genetic testing can confirm the presence of LMX1B gene mutations and help guide treatment and monitoring strategies.