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.
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.
ARPKD is diagnosed in the following ways:
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.
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.
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.
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.
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.