Should members of the family have tests to look for Alport’s Syndrome?

This description of the inheritance of Alport’s syndrome applies to the 9 out of 10 families who have the commoner genetic problem. Some families are more complicated, and advice should be taken from a specialist in genetics.

The need for testing family members will be discussed from the point of view of a man with Alport’s syndrome, and then from the point of view of a woman with Alport’s syndrome.

Who to test if a man has Alport’s syndrome

His parents

Alport’s syndrome should have been inherited from his mother, though occasionally the genetic abnormality has occurred for the first time in the affected person. His mother should have urine tests for blood. If there is blood in the urine, kidney function and blood pressure should be tested, and a kidney specialist consulted. If the mother is completely clear, the father should be checked, in case there is a rarer variant of Alport’s syndrome.

His brothers

There is a 50:50 chance that a brother will have Alport’s syndrome. Urine should be tested for blood. If he has blood in the urine, kidney function and blood pressure should be measured, and a kidney specialist consulted. A brother might have Alport’s syndrome, and could pass this onto his daughters. If there is no blood in the urine on several tests, he should not have the Alport’s syndrome gene, and so cannot pass the condition onto his children.

His sisters

There is a 50:50 chance that each sister will have Alport’s syndrome, though remember that this is less serious in women than in men. Urine should be tested for blood. If she has blood in the urine, kidney function and blood pressure should be measured, and a kidney specialist consulted. If she has Alport’s syndrome, she could pass this onto her children. If there is no blood in the urine on several tests, she should not have Alport’s syndrome, and so cannot pass the condition onto her children.

His sons

A man with Alport’s syndrome cannot pass the condition onto his sons (unless he has one of the rarer variants of the disease). This is because the abnormal gene is on the ‘X’ chromosome, and in order to have a son, a man has to pass on his ‘Y’ chromosome to the child, and this does not carry Alport’s syndrome (for more information on ‘X’ and ‘Y’ chromosomes in Alports syndrome, click here).

His daughters

Each daughter will have Alport’s syndrome, though remember that this is less serious in women than in men. Urine should be tested for blood to confirm the diagnosis. Kidney function and blood pressure should be measured, and a kidney specialist consulted. She could pass Alport’s syndrome onto her children (see below).

Who to test if a woman has Alport’s syndrome

Her parents

Alport’s syndrome should have been inherited from her mother or father. Her parents should have urine tests for blood. If there is blood in the urine, kidney function and blood pressure should be tested, and a kidney specialist consulted.

Her brothers

If Alport’s syndrome is inherited from the father, the male children should not have the syndrome. If Alport’s is inherited from the mother’s side, there is a 50:50 chance that he will have Alport’s syndrome. Urine should be tested for blood. If there is blood in the urine, kidney function and blood pressure should be measured, and a kidney specialist consulted. He might have Alport’s syndrome, and could pass this onto his daughters. If there is no blood in the urine on several tests, he should not have Alport’s syndrome, and so cannot pass the condition onto his children.

Her sisters

If Alport’s syndrome is inherited from the father, the female children should all have Alport’s syndrome. If Alport’s syndrome is inherited from the mother’s side, there is a 50:50 chance that the sister will have Alport’s syndrome. Urine should be tested for blood. If there is blood in the urine, kidney function and blood pressure should be measured, and a kidney specialist consulted. She might have Alport’s syndrome, and could pass this onto her children. If there is no blood in the urine on several tests, she should not have Alport’s syndrome, and so cannot pass the condition onto her children.

Her sons

There is a 50:50 chance that each son would have Alport’s syndrome. Urine should be tested for blood. If there is blood in the urine, kidney function and blood pressure should be measured, and a kidney specialist consulted. He might have Alport’s syndrome, and could pass this onto his daughters. If there is no blood in the urine on several tests, he should not have Alport’s syndrome, and so cannot pass the condition onto his children.

Her daughters

There is a 50:50 chance that a daughter will have Alport’s syndrome. Urine should be tested for blood. If there is blood in the urine, kidney function and blood pressure should be measured, and a kidney specialist consulted. She might have Alport’s syndrome, and could pass this onto her children. If there is no blood in the urine on several tests, she should not have Alport’s syndrome, and so cannot pass the condition onto her children.

NKF Controlled Document No. 53, Should members of the family have tests to look for Alport’s Syndrome?, written 2 September 2002. Last reviewed 29 November 2010.

The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.

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