Congenital hepatic fibrosis is a disease of the liver that is present from birth. The liver has many important functions, including producing various substances needed by the body and breaking down other substances into smaller parts to be used or removed from the body.\n\nCongenital hepatic fibrosis is characterized by abnormal formation of the bile ducts and the blood vessels of the hepatic portal system. Bile ducts carry bile (a fluid that helps to digest fats) from the liver to the gallbladder and small intestine. The hepatic portal system is a branching network of veins (portal veins) that carry blood from the gastrointestinal tract to the liver for processing.\n\nA buildup of scar tissue (fibrosis) in the portal tracts also occurs in this disorder. Portal tracts are structures in the liver that bundle the vessels through which blood, lymph, and bile flow. Lymph is a fluid that helps exchange immune cells, proteins, and other substances between the blood and tissues. Fibrosis in the portal tracts can restrict the normal movement of fluids in these vessels.\n\nNarrowing of the portal veins due to malformation and portal tract fibrosis results in high blood pressure in the hepatic portal system (portal hypertension). Portal hypertension impairs the flow of blood from the gastrointestinal tract, causing an increase in pressure in the veins of the esophagus, stomach, and intestines. These veins may stretch and their walls may become thin, leading to a risk of abnormal bleeding.\n\nPeople with congenital hepatic fibrosis have an enlarged liver and spleen (hepatosplenomegaly). The liver is also abnormally shaped. Affected individuals also have an increased risk of infection of the bile ducts (cholangitis), hard deposits in the gallbladder or bile ducts (gallstones), and cancer of the liver or gallbladder.\n\nCongenital hepatic fibrosis may occur alone, in which case it is called isolated congenital hepatic fibrosis. More frequently, it occurs as a feature of genetic syndromes that also affect the kidneys, such as polycystic kidney disease (PKD).

Renal hypodysplasia/aplasia belongs to a group of perinatally lethal renal diseases, including bilateral renal aplasia, unilateral renal agenesis with contralateral dysplasia (URA/RD), and severe obstructive uropathy. Renal aplasia falls at the most severe end of the spectrum of congenital anomalies of the kidney and urinary tract (CAKUT; 610805), and usually results in death in utero or in the perinatal period. Families have been documented in which bilateral renal agenesis or aplasia coexists with unilateral renal aplasia, renal dysplasia, or renal aplasia with renal dysplasia, suggesting that these conditions may belong to a pathogenic continuum or phenotypic spectrum (summary by Joss et al., 2003; Humbert et al., 2014). Genetic Heterogeneity of Renal Hypodysplasia/Aplasia See also RHDA2 (615721), caused by mutation in the FGF20 gene (605558) on chromosome 8p22; RHDA3 (617805), caused by mutation in the GREB1L gene (617782) on chromosome 18q11; and RHDA4 (619887), caused by mutation in the GFRA1 gene (601496) on chromosome 10q25.

MARCH is an autosomal recessive lethal congenital disorder characterized by severe hydranencephaly with almost complete absence of the cerebral hemispheres, which are replaced by fluid, relative preservation of the posterior fossa structures, and renal dysplasia or agenesis. Affected fetuses either die in utero or shortly after birth, and show arthrogryposis and features consistent with anhydramnios. Histologic examination of residual brain tissue shows multinucleated neurons resulting from impaired cytokinesis (summary by Frosk et al., 2017).

Any renal-hepatic-pancreatic dysplasia in which the cause of the disease is a mutation in the NPHP3 gene.

Renal hypodysplasia/aplasia belongs to a group of perinatally lethal renal diseases, including bilateral renal aplasia, unilateral renal agenesis with contralateral dysplasia (URA/RD), and severe obstructive uropathy. Renal aplasia falls at the most severe end of the spectrum of congenital anomalies of the kidney and urinary tract (CAKUT; 610805), and usually results in death in utero or in the perinatal period. Families have been documented in which bilateral renal agenesis or aplasia coexists with unilateral renal aplasia, renal dysplasia, or renal aplasia with renal dysplasia, suggesting that these conditions may belong to a pathogenic continuum or phenotypic spectrum (summary by Joss et al., 2003; Humbert et al., 2014). For a discussion of genetic heterogeneity of renal hypodysplasia/aplasia, see RHDA1 (191830).

Renal hypodysplasia/aplasia-4 (RHDA4) is characterized by bilateral renal agenesis, with severely reduced to absent amniotic fluid during pregnancy. Patients exhibit the Potter sequence, including flattened nose, ear anomalies, and receding chin, as well as limb contractures and joint dislocations in some patients (Arora et al., 2021; Al-Shamsi et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of renal hypoplasia/dysplasia, see RHDA1 (191830).

An instance of renal tubular dysgenesis that is caused by a modification of the individual's genome.