[Molecular and clinical characteristics of a family with Alagille syndrome].

Background And Objective: The Alagille syndrome (AS) is characterized by biliary ductopenia and abnormalities of heart, eyes, face, bones, kidneys and brain with a dominant inheritability. Mutations of Jagged 1 gene are observed in individuals with the full syndrome and/or relatives with little or no phenotypic features. Prognosis of patients depends on the hepatic and cardiovascular involvement.

Biological function of mutant forms of JAGGED1 proteins in Alagille syndrome: inhibitory effect on Notch signaling.

Heterozygous mutations in JAGGED1, encoding a single-pass transmembrane ligand for the Notch receptors, cause Alagille syndrome (AGS), a polymalformative disorder affecting the liver, heart, eyes and skeleton and characterized by a peculiar facies. Most of the JAGGED1 mutations generate premature termination codons, and as a result, two pathogenic mechanisms causing AGS have been proposed: haploinsufficiency or a dominant-negative effect of putative truncated proteins. To determine whether missense or protein-truncating mutations in JAGGED1 can lead to the synthesis and function of abnormal proteins, we performed cell culture experiments.

Prenatal molecular diagnosis of inherited cholestatic diseases.

Objectives: Progressive familial intrahepatic cholestasis (PFIC) and to a lesser extent, Alagille syndrome, often lead to end-stage liver disease during childhood. We report our experience of DNA-based prenatal diagnosis of PFIC1-3 and Alagille syndrome.

Patients And Methods: Four molecular antenatal diagnoses were performed in 3 PFIC families and 17 in 11 Alagille syndrome families.

Expression of mutant JAGGED1 alleles in patients with Alagille syndrome.

Heterozygous mutations in JAGGED1 (JAG1), encoding a ligand for Notch receptors, have been identified in patients with Alagille syndrome (AGS). These mutations map to the extracellular and transmembrane domains of JAG1, giving rise in 70% cases to a premature termination codon (PTC). Although haploinsufficiency has been hypothesised as the main mechanism of AGS, a dominant negative effect of truncated forms of Serrate/Jagged has been suggested.

Bleeding tendency in children with Alagille syndrome.

Objective: Spontaneous intracranial bleeding is now a widely recognized complication and cause of mortality in patients with Alagille syndrome. The pathogenesis of intracranial bleeding in these patients remains unclear. The aim of the study was to look for other sites of bleeding in these patients that could suggest a factor of multiorgan morbidity.