Autosomal recessive polycystic kidney disease
Autosomal recessive polycystic kidney disease is a recessive inheritance disorder characterized by a variable combination of multiple cysts in both kidneys and congenital hepatic fibrosis.
It has an incidence of 1 / 20,000 live births and its manifests producing a severe pathology during gestation or in the first months of life, rarely in adolescence.
In the etiology, is involved a gene located at the 6-6p21.1-p12 position, called PKHD1. The different phenotypic expressions of this disease are due to multiple mutations of this gene. It is known to encode a protein called fibrocystin that has been identified in organs that are affected by the disease (liver, kidneys and pancreas), being its fundamental role in the differentiation of the renal tubules and bile ducts.
Molecular genetics allows a reliable diagnosis from 12 weeks of gestation, in approximately 80% of the family affected population.
Autosomal recessive polycystic kidney disease is characterized by variable dilatation of the collecting tubules and bile ducts. This is why the typical appearance of large kidneys with numerous microcysts corresponding to collecting tubules dilated by fluid accumulated in their interior. The numerous cysts exerted a compressive effect on the healthy parenchyma, giving rise to the progressive destruction of nephrons. This justifies the low intrauterine diuresis of the fetus, which leads to oligohydramnios and consequently pulmonary hypoplasia.
In most cases, autosomal recessive polycystic kidney disease is evident at birth, and ultrasound findings are found at weeks 14 to 17 of gestation in the most severe cases, but generally, between 24 and 30 weeks, being late to be able to perform a prenatal diagnosis.
The most characteristic ultrasound findings are increased renal size, oligoamnios and lack of bladder filling.
Cases associated with pulmonary hypoplasia may be incompatible with life. Hypertension is frequent and occurs early in the disease.
The treatment of this disease is symptomatic and supportive. It responds well to angiotensin II converting enzyme inhibitors and to calcium channel blockers. Chronic renal failure is treated conservatively, preventing renal osteodystrophy as much as possible, treating anemia and growth retardation. The goal of treatment is to control symptoms and prevent complications. Treatment may also include diuretics and a low salt diet.
Definitive treatment is renal transplantation, but the degree of liver damage must be assessed, which is sometimes so important that he needs liver transplantation. Approximately half of people with polycystic kidney disease have cysts in the liver.
Survival depends on severity in the neonatal period. There are recent studies showing that 50% of these children survive to 15 years of age. The renal prognosis of children over the first month of life is good, with maintenance of renal function in 75% of cases at 15 years. There are less severe cases in which the detection of cysts happens in adulthood, the disease in these cases worsens slowly. Over time, it can lead to terminal renal failure. It is also associated with liver disease, which includes infection of cysts in the liver. Treatment can provide symptom relief for many years. People with polycystic kidney disease who do not have other diseases may be good candidates for a kidney transplant.
Gene or region studied