What causes nail patella syndrome?

Most people with nail patella syndrome will have inherited a defective version of a gene called LMX1B from one of their parents. This gene is important in the development of a baby's limbs, nails, kidneys and eyes.

Only one of the two copies of the gene needs to be faulty for a person to be affected (dominant inheritance). This means a child of someone with nail patella syndrome has a 50% chance of inheriting the condition.

However, there is not always a family history of nail patella syndrome. In some cases, the LMX1B gene will have mutated (altered) spontaneously.

However, when the diagnosis is not clear, a genetic blood test can be used to confirm the diagnosis by finding out whether a person is carrying a mutated LMX1B gene. A mutation in this gene can be identified in 95% of people with nail patella syndrome.

Genetic testing can also be carried out during pregnancy to find out if a child will be born with nail patella syndrome, although this cannot predict how severe the condition will be.

Another option for couples at risk of havinga child with nail patella syndrome is a technique calledpre-implantation genetic diagnosis (PGD).

This involves testing embryos that have been fertilised using in vitro fertilisation (IVF) , and only implanting embryos that have not inherited nail patella syndrome into the womb.

Before genetic testing or PGD, genetic counselling will be offered. This service is provided by healthcare professionals specially trained in the science of human genetics (a genetic counsellor or a clinical geneticist) and is available at regional genetics centres across the country.

The counsellor will discuss the risks, benefits and limitations of genetic testing. They will also explainhow the information found as a result of genetic testing could have implications for both you and your family.

However, long-term use of non-steroidal anti-inflammatory drug (NSAID) painkillers should be avoided, because these can affect the kidneys.

Some people may need correctivesurgery for problems with the bones and joints.

Annual urine tests to look for kidney problems shouldbegin at birth.If problems develop, thesemay need to be controlled with medication or dialysis , where a machine is used toreplicate many of the kidneys functions. People withsevere kidney disease may need to have a kidney transplant .

Women with high blood pressure caused by kidney problems will need to be carefully monitored if they become pregnant, as pregnancy can make high blood pressure worse.

Screening for glaucoma shouldstart in the teenage years and be repeated at least every two years. Treatment for glaucoma may involve using eye drops or having a procedure to reduce the pressure inside the eye.

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the NCARDRSregister .