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Short-rib thoracic dysplasia (SRTD) with or without polydactyly refers to a group of autosomal recessive skeletal ciliopathies that are characterized by a constricted thoracic cage, short ribs, shortened tubular bones, and a 'trident' appearance of the acetabular roof. SRTD encompasses Ellis-van Creveld syndrome (EVC) and the disorders previously designated as Jeune syndrome or asphyxiating thoracic dystrophy (ATD), short rib-polydactyly syndrome (SRPS), and Mainzer-Saldino syndrome (MZSDS). Polydactyly is variably present, and there is phenotypic overlap in the various forms of SRTDs, which differ by visceral malformation and metaphyseal appearance. Nonskeletal involvement can include cleft lip/palate as well as anomalies of major organs such as the brain, eye, heart, kidneys, liver, pancreas, intestines, and genitalia. Some forms of SRTD are lethal in the neonatal period due to respiratory insufficiency secondary to a severely restricted thoracic cage, whereas others are compatible with life (summary by Huber and Cormier-Daire, 2012 and Schmidts et al., 2013). There is phenotypic overlap with the cranioectodermal dysplasias (Sensenbrenner syndrome; see CED1, 218330). For a discussion of genetic heterogeneity of short-rib thoracic dysplasia, see SRTD1 (208500). [from OMIM]

COACH syndrome is classically defined as Cerebellar vermis hypoplasia, Oligophrenia, Ataxia, Colobomas, and Hepatic fibrosis (Verloes and Lambotte, 1989). Brain MRI demonstrates the molar tooth sign, which is a feature of Joubert syndrome. The disorder has been described as a Joubert syndrome-related disorder with liver disease (summary by Doherty et al., 2010). For a general phenotypic description and a discussion of genetic heterogeneity of COACH syndrome, see 216360. [from OMIM]

Biliary, renal, neurologic, and skeletal syndrome (BRENS) is an autosomal recessive complex ciliopathy with multisystemic manifestations. The most common presentation is severe neonatal cholestasis that progresses to liver fibrosis and cirrhosis. Most patients have additional clinical features suggestive of a ciliopathy, including postaxial polydactyly, hydrocephalus, retinal abnormalities, and situs inversus. Additional features of the syndrome may include congenital cardiac defects, echogenic kidneys with renal failure, ocular abnormalities, joint hyperextensibility, and dysmorphic facial features. Some patients have global developmental delay. Brain imaging typically shows dilated ventricles, hypomyelination, and white matter abnormalities, although some patients have been described with abnormal pituitary development (summary by Shaheen et al., 2020 and David et al., 2020). [from OMIM]

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.

Congenital 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.

A 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.

Narrowing 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.

People 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.

Congenital 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). [from MedlinePlus Genetics]