Autosomal recessive polycystic kidney syndrome (ARPKD). What we need to know

21.11.2022

A cyst is a formation filled with liquid. It comes in different sizes and appears in different areas of the body. The term "poly" means many, polycystic polycystic.

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Polycystic kidney disease is a pathology in which many cysts appear in the kidneys. These cysts are benign in nature and develop from the renal tubules. It should be noted that healthy people, especially the elderly, sometimes have one, two or several cysts in the kidney.

As a rule, such cysts do not pose a threat to health and are not a manifestation of polycystic disease. Polycystic kidney disease is genetic in nature. This means that one or more genes are changed in the human body, which causes the formation of many cysts in the kidney. Several types of polycystic kidney disease are distinguished:

autosomal dominant. This type is the most common. It is a congenital pathology, the cause of which is a gene received from one of the parents. Symptoms of the disease and health problems related to the pathology appear mostly in adulthood.
autosomal recessive. This is a rare condition that affects 20 in 000 people. Problems, as a rule, appear shortly after birth. This type of polycystic kidney disease develops when a person inherits the abnormal gene from both parents. In this case, the parents are healthy, but carry the abnormal gene.

Autosomal recessive polycystic kidney syndrome (ARPK)

A fetus or child with ARPK has a fluid-filled kidney cyst, which can cause the kidneys to grow in size and function.

Polycystic kidney disease is "autosomal recessive" if both parents of the child are carriers of the abnormal gene. If only one parent carries the abnormal gene, the child has a lower risk of developing the disease, although he may inherit the abnormal genes and pass them on to his offspring.

In autosomal recessive polycystic kidney disease (ARKD), symptoms may appear in utero when small cysts form in the end section of the nephron, called the collecting duct. A cyst is a balloon-shaped extension of a tube. Due to the large number of nephrons with a small balloon-like expansion, the kidneys can grow significantly. In addition, the normal function of collecting ducts is disturbed.

In a normal kidney, the collecting duct fine-tunes the amount of water and acid in the tubular fluid so that the body retains the appropriate amount of water and expels excess acid. In ARPKD, the cystic collecting ducts fail to clear water, causing much more urine to be produced than in children with normal kidneys.

Complications

underdeveloped lungs, which can cause breathing difficulties soon after birth;
high blood pressure (hypertension);
excessive urination and thirst;
problems with blood flow to the liver, which can cause serious internal bleeding;
A progressive loss of kidney function known as chronic kidney disease (CKD).

Symptoms

Prenatal symptoms:

Decrease in amniotic fluid level during pregnancy;
enlarged kidneys on fetal ultrasound;
underdeveloped lungs and functional problems;

Symptoms at birth:

significant difficulty in breathing - this is caused by the underdevelopment of the lungs;
A swollen abdomen is caused by an enlarged kidney;
Potter's syndrome - lack of amniotic fluid causes deformation of limbs, face and ears; Potter syndrome is possible in severe cases of ARPKD;
high blood pressure (hypertension);
liver problems and internal bleeding;
feeding problems;
slow growth;
kidney failure;
congenital liver fibrosis;
An enlarged spleen with low levels of red blood cells, white blood cells, and platelets.

Prevention

Early signs of ARPKD are sometimes visible during the first routine ultrasound scan performed at 12 weeks of pregnancy, although the syndrome is not usually detected until the second routine scan at around 20 weeks.

ARPKD can only be passed to a child if both parents have the faulty PKHD1 gene. If you have a genetic history of ARPKD and are planning to have a child, it is advisable to consult a geneticist in time to correctly and safely manage the pregnancy and avoid prenatal health problems related to the fetus.

Online consultation of a geneticist in Synevo - (https://synevo.ge/genetikosis-konsultacia-online/)

Diagnosis

All newborns are screened through a blood test. There are also newer tests that can be used to determine whether the fetus has mutated genes at an early stage of pregnancy through safe testing methods (Veragen (100 monogenic diseases)). Also, if there is a risk of transmitting the disease to the child, couples can consult a specialist before the birth and manage the pregnancy properly.

Screening tests – A prenatal screening test can determine if your baby is more or less likely to have birth defects, many of which are genetic disorders.

These tests include blood tests, specific ultrasounds, and prenatal cell-free DNA screening. If screening tests show that you or your fetus has a high risk of autosomal recessive polycystic kidney syndrome, it is recommended that you also have a diagnostic test to determine whether the fetus has the genetic disorder.

Diagnostic tests – After the screening test, the final answer is given by a diagnostic test that examines the genetic material of the fetus and therefore can determine whether the fetus has a genetic disorder. Invasive and non-invasive prenatal diagnostic tests ((NIPT) Verasity, Veragen) are the only, safe and effective way to confirm the diagnostics.

Be aware that some prenatal diagnostic tests, such as chorionic villus sampling and amniocentesis, carry a small risk of miscarriage.

Learn more about prenatal diagnostics → (https://synevo.ge/prenatal-screening/)

Treatment

Currently, ARPKD cannot be completely cured, but various treatments can manage the wide range of problems it causes.

Treatment for ARPKD may include:

Breathing assistance through special medical devices;
Medicines to treat high blood pressure;
various types of surgical manipulations and procedures to stop internal bleeding;
Medicines to control problems related to reduced kidney function, such as iron supplements for anemia.
In case of kidney failure: surgical interventions (kidney transplantation).