What is ARPKD?

ARPKD is a rare form of PKD diagnosed in infants, either before or after birth or later in young children. The most severely affected babies may not survive the first few months. If the child survives the newborn period, the chances of survival are good. For these children, approximately half will need dialysis or a kidney transplant by the age of 10.

Fast Facts about Autosomal Recessive Polycystic Kidney Disease

•    ARPKD is a rare disease that affects the kidney and liver

•    In the general public, 1 in 70 is a carrier. 

•    It is estimated that between 65 and 76% of children with ARPKD also have high blood pressure. 

•    About 1 in 3 babies with ARPKD die from breathing problems within the 
first four weeks of life. 

•    80-90% of babies that survive the first four weeks of life are still alive at 
the age of 5. 

•    There is very little scientific investigation into how many children survive 
into adulthood.

What causes ARPKD?

ARPKD is an inherited disease, in which the infant receives two abnormal genes. Parents of children with ARPKD do not have kidney disease because they each have one normal gene and one abnormal gene, rather they are carriers of the disease. When both parents are carriers, the chance of each child inheriting the abnormal gene is 1 in 4. If the child receives only one copy of the mutated gene, they will not have ARPKD but will be a carrier.

When is ARPKD diagnosed?

ARPKD is diagnosed in the following ways
The first sign of ARPKD is enlarged kidneys, which may be seen on the 18 – 20 week routine ultrasound scan of the pregnancy. The kidneys will continue to enlarge markedly during pregnancy and there may be a decrease in the amount of fluid around the baby. If there is less fluid produced in the second half of pregnancy, the lungs may have difficulty forming and may also be compressed by the very large kidneys.
At birth the infant may have an enlarged abdomen and smaller chest. ARPKD affects the following organs as well as the kidneys. Liver – The liver may be slightly enlarged. Lungs – if the kidneys are very badly affected before birth, the baby’s lungs may not fully develop. This can result in breathing difficulties and the baby may require assistance with breathing. Feeding – when the baby’s kidneys are enlarged, they may only be able to take small amounts of feeds at any one time so may require assistance with tube feeding.
Children who are diagnosed later with ARPKD have less severe kidneys problems.  They may also develop high blood pressure later, which needs to be treated.

How is ARPKD treated?

Newborn infants may require blood pressure medication. Once the blood pressure is controlled the doses may not need much adjustment as the child grows. Children with mild kidney problems may not need any treatment or may only require medication to control high blood pressure. The most important element in treatment is controlling blood pressure to slow the reduction in kidney function.  When kidney function in an infant deteriorates to less than 10% dialysis and transplantation need to be considered.

What is the outlook for a child with ARPKD?

The outlook for children with ARPKD depends on the severity of the child’s disease. Usually the earlier the disease is diagnosed the more severe it is. The majority of children with ARPKD develop kidney failure at any time from very early childhood into early adulthood. 

Genetic testing and antenatal counselling

The genetics that cause ARPKD are due to abnormalities in the PKHD1 gene. Tests can be performed to confirm the diagnosis of ARPKD or if the parents already have a child with ARPKD and are concerned about the risk of subsequent children being affected. Prenatal genetic testing can be undertaken in early pregnancy. This involves testing small samples of amniotic fluid and tissue from the placenta, together with ultrasound scans.  Genetic counselling is available for parents considering further children.

Is there a cure for ARPKD?

Currently there is no cure for ARPKD, which is why the PKD Foundation is raising money to fund medical research into finding a cure and raising awareness of the disease in Australia.

How can i prolong my child’s kidney health?

Children with ARPKD are encouraged to be active, eat healthily and participate in sports, as the strong back muscles protect children’s kidneys. Motorised trail bike jumping is discouraged because of the possibility of high impact injury from the handlebars. 

Helpful resources

Below is a list of valuable resources that will be updated over time:

PKD Charity – About ARPKD

PKD Foundation – What is ARPKD