Question & Answer

Are there treatments or cures?
Currently, there are no treatments or cures for ARPKD/CHF.  Medical care is dependent on other diseases, but if the newborn period is survived, there is potential for an excellent quality lifestyle with medical management.

What causes APRKD/CHF?
ARPKD/CHF is inherited.  As a fetus begins to develop, the formation of the kidneys in ARPKD and the liver in CHF are affected.  Eventually the kidney collecting tubules become cystic and dilated.  It is believed that with CHF, ductal plate development never completes, resulting in ductal plate malformation.

What is the inheritance pattern?
This is a recessive disease.  For a recessive trait or disease to occur, both parents must carry and pass on the defective gene.  Even though parents are “carriers” of the ARPKD gene, they never have the disease or symptoms.  There is a 25% chance of the disorder occurring with each pregnancy when parents are “carriers” of the gene.  Typically there is no family history of the disease.

What is the difference between ADPKD and ARPKD?
ADPKD is the dominant (meaning at least 1 parent has it) form of PKD.  It generally manifests itself with kidney decline much later than ARPKD. 

ARPKD is the recessive type (neither parent has it) and is considered a much more serious, life threatening disease.  It affects primarily newborns; kidney failure may occur early in life, and the CHF component can be especially troublesome.

When is a patient with ARPKD usually diagnosed?
It is commonly diagnosed very early in life.  Up to 40% are diagnosed prenatally.

Is this a liver or kidney disease?
Both, it should be viewed as a combination of both the kidneys and liver.

What gene affects ARPKD/CHF?
Abnormalities in a single gene (PKHD1) appear to cause greater then 99% of all ARPKD/CHF cases.  It takes one of these defective genes from each parent for the "recessive" disorder to be present.

What are the top complications of ARPKD?
The mortality in neonates/newborn is very high.  Early newborn death occurs up to 50% of the time, most often not from kidney failure, but from pulmonary hypoplasia (underdeveloped lungs).  If ventilatory support is offered and the newborn period is survived, then the chances of survival increase to good.  Most survivors develop chronic kidney failure before the age of 30 years.

What is CHF?
CHF is malformation of the bile ducts that is sometimes referred to as Ductal Plate Malformation.  This malformation is associated with biliary ectasia (bile duct dilatation) and scarring of the liver in the portal tracts, which carry blood to the liver and bile away from the liver.

How does someone get CHF?
It is an inherited defect which affects both the kidneys and liver.  It is uncommon for a person to have CHF without ARPKD.  However, if a person has ARPKD they always have some degree of CHF.

What effect can CHF have?
The portal vein, which carries large amounts of blood to and through the liver, and the bile ducts, which carry bile away from the liver, is both part of the “plumbing system”.  They normally have unrestricted flow, but with CHF this may be greatly reduced... these areas fill with scar tissue (fibrosis) creating blood flow resistance and turbulence.

What is the impact of CHF?
CHF has the potential to cause severe clinical liver complications.  Slow blood flow results in a “backup pressure” within the vessels that feed the portal vein.  This backup pressure results in increased pressure in the portal vein (portal hypertension).  This can lead to mild to massive gastrointestinal bleeding, low white cell counts, low hemoglobin and low platelet counts (from hypersplenism).  CHF may also be complicated by cholangitis.

What is Caroli's Syndrome?
Many professionals consider Caroli's Syndrome as part of the CHF spectrum.

What research is being done?
Currently there is a great deal of studies being done on PKD in general, but there is almost no research being done solely on non-inflammatory  Hepatic Fibrosis.  It is very unfortunate, because CHF can be especially life threatening.