Autosomal recessive polycystic kidney disease
Autosomal recessive polycystic kidney disease is a rare, inherited childhood condition, where development of the kidneys and liver is abnormal. Over time, either one of these organs may fail. It often causes serious problems soon after birth, although less severe cases may not become obvious until a child is older.
Causes of ARPKD
ARPKD is caused by a genetic fault that disrupts normal development of the kidneys and liver.
ARPKD is caused by a genetic alteration in the gene PKHD1, which in most cases is passed on to a child by their parents.
If both parents carry a faulty version of this gene, there's a one in four chance of each child they have developing ARPKD.
The way ARPKD is inherited is different from a more common type of kidney disease called autosomal dominant polycystic kidney disease (ADPKD).
ADPKD usually doesn't cause significantly reduced kidney function until adulthood.
ADPKD can be inherited if only one parent carries one of the genetic faults responsible for the condition.
About autosomal recessive polycystic kidney disease (ARPKD)
The symptoms of autosomal recessive polycystic kidney disease (ARPKD) can vary significantly, even within the same family.
Generally, however, the main symptoms of ARPKD differ, depending on when the condition first becomes clear.
Before and soon after birth
In many cases, potential signs of ARPKD can be detected before birth during routine ultrasound scans.
If your baby has the condition, an ultrasound scan may show that:
- they have enlarged or "bright" kidneys
- their lungs are underdeveloped
- there's a lack of amniotic fluid surrounding your baby
When your baby is born, there may be clearer signs that suggest they have ARPKD, such as:
- significant breathing difficulties – this is caused by the lungs being underdeveloped
- a swollen abdomen (tummy) – caused by enlargement of the kidneys
- Potter's syndrome – where a lack of amniotic fluid leads to deformities of the limbs, face and ears
Potter's syndrome is a possibility in severe cases of ARPKD.
Underdeveloped lungs would be the biggest problem immediately after birth and breathing assistance with a ventilator is often needed.
A ventilator is a machine that moves air in and out of the lungs.
Unfortunately, even with treatment, around one in every three babies with ARPKD who develop breathing difficulties soon after birth will die within a few weeks or months.
If a baby survives this stage, the chance of long-term survival is much better and around 90 per cent of those who survive these early stages will live for 10 years. However, about a third of these children will need treatment for kidney failure.
Infants and children
ARPKD tends to be less immediately life-threatening in infants and older children, although the condition can still cause a wide range of serious problems.
Some of the main problems infants and children with ARPKD experience are described below.
High blood pressure
If your child has high blood pressure, they'll usually need to take medication to lower it and prevent long-term damage to their heart and blood vessels.
Excessive urination and thirst
Kidney abnormalities cause cysts (fluid-filled sacs) to form affecting kidney function, causing loss of too much body fluid as urine leading to thirst and dehydration.
Chronic kidney disease and kidney failure
Most children with ARPKD will develop kidney failure by the time they're 15 to 20 years old.
Feeding problems
Enlarged kidneys can take up most of the space in the abdomen (tummy) causing vomiting after eating and they may only be able to eat small amounts at a time, leading to malnourishment.
Faltering growth or failure to thrive
Some children with ARPKD don't grow at a normal rate.
Children with ARPKD are usually under the care of a dietitian, who may recommend a high-calorie and high-protein diet to boost their weight.
Sometimes being fed through a tube is required.
Liver problems and internal bleeding
For children with ARPKD, a number of problems affecting the liver can also develop.
The small tubes that allow bile (a digestive fluid) to flow out of the liver may develop abnormally and cysts may grow inside them.
The liver can also develop fibrosis (a process similar to scarring) which blocks the blood flow through the liver and increases the pressure in its delicate blood vessels (portal hypertension).
Blood bypasses the liver and is diverted into veins in the lower gullet (oesophagus). If the veins get too big they can bleed, causing vomiting of blood.
Portal hypertension also diverts blood to the spleen, causing it to become bigger than normal. When enlarged it can filter too many cells from the blood (including ones that help blood clot), increasing the risk of bleeding.
Treating ARPKD
There's no cure for ARPKD. But various treatments can help manage the wide range of problems it can cause.
Treatment for ARPKD may include:
- breathing assistance with a ventilator (a machine that moves air in and out of the lungs) for children with severe breathing difficulties
- medication to treat high blood pressure
- procedures to stop any internal bleeding that may occur
- medications to control problems associated with the loss of kidney function, such as iron supplements for anaemia
If kidney failure does occur, there are two main treatment options:
- dialysis – where a machine is used to replicate many functions of the kidney
- kidney transplant – where a healthy kidney is removed from a living or recently deceased donor and implanted into someone with kidney failure
Outlook
The outlook for children with ARPKD can vary considerably, depending on the severity of the condition.
With advances in treatments and a better understanding of the condition, increasing numbers of children with ARPKD are living well into adulthood.
More useful links
The information on this page has been adapted from original content from the NHS website.
For further information see terms and conditions.