@article {34, title = {Mutations in DCDC2 (doublecortin domain containing protein 2) in neonatal sclerosing cholangitis.}, journal = {J Hepatol}, volume = {65}, year = {2016}, month = {2016 Dec}, pages = {1179-1187}, abstract = {

BACKGROUND \& AIMS: Neonatal sclerosing cholangitis (NSC) is a severe neonatal-onset cholangiopathy commonly leading to liver transplantation (LT) for end-stage liver disease in childhood. Liver biopsy findings histopathologically resemble those in biliary atresia (BA); however, in NSC extrahepatic bile ducts are patent, whilst in BA their lumina are obliterated. NSC is commonly seen in consanguineous kindreds, suggesting autosomal recessive inheritance.

METHODS: From 29 NSC patients (24 families) identified, DNA was available in 24 (21 families). Thirteen (7 male) patients (12 families) of consanguineous parentage were selected for whole exome sequencing. Sequence variants were filtered for homozygosity, pathogenicity, minor allele frequency, quality score, and encoded protein expression pattern.

RESULTS: Four of 13 patients were homozygous and two were compound heterozygous for mutations in the doublecortin domain containing 2 gene (DCDC2), which encodes DCDC2 protein and is expressed in cholangiocyte cilia. Another 11 patients were sequenced: one (with one sibling pair) was compound heterozygous for DCDC2 mutations. All mutations were protein-truncating. In available liver tissue from patients with DCDC2 mutations, immunostaining for human DCDC2 and the ciliary protein acetylated alpha-tubulin (ACALT) showed no expression (n=6) and transmission electron microscopy found that cholangiocytes lacked primary cilia (n=5). DCDC2 and ACALT were expressed in NSC patients without DCDC2 mutations (n=22). Of the patients carrying DCDC2 mutations, one died awaiting LT; five came to LT, of whom one died 2years later. The other 4 are well.

CONCLUSION: Among 24 NSC patients with available DNA, 7 had mutations in DCDC2 (6 of 19 families). NSC patients in substantial proportion harbour mutations in DCDC2. Their disease represents a novel liver-based ciliopathy.

LAY SUMMARY: Neonatal sclerosing cholangitis (NSC) is a rare genetic form of liver disease presenting in infancy. Through next generation sequencing we identified mutations in the gene encoding for doublecortin domain containing 2 (DCDC2) protein in a group of NSC children. DCDC2 is a signalling and structural protein found in primary cilia of cholangiocytes. Cholangiocytes are the cells forming the biliary system which is the draining system of the liver.

}, keywords = {Cholangitis, Sclerosing, Female, High-Throughput Nucleotide Sequencing, Humans, Infant, Newborn, Male, Microtubule-Associated Proteins, Mutation}, issn = {1600-0641}, doi = {10.1016/j.jhep.2016.07.017}, author = {Grammatikopoulos, Tassos and Sambrotta, Melissa and Strautnieks, Sandra and Foskett, Pierre and Knisely, A S and Wagner, Bart and Deheragoda, Maesha and Starling, Chris and Mieli-Vergani, Giorgina and Smith, Joshua and Bull, Laura and Thompson, Richard J} } @article {81, title = {Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis.}, journal = {Nat Commun}, volume = {7}, year = {2016}, month = {2016 Feb 18}, pages = {10713}, abstract = {

Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection.

}, keywords = {ATP Binding Cassette Transporter, Subfamily B, Member 11, ATP-Binding Cassette Transporters, Bile Acids and Salts, Cholestasis, Intrahepatic, Female, Humans, Male, Mutation, Receptors, Cytoplasmic and Nuclear, Young Adult}, issn = {2041-1723}, doi = {10.1038/ncomms10713}, author = {Gomez-Ospina, Natalia and Potter, Carol J and Xiao, Rui and Manickam, Kandamurugu and Kim, Mi-Sun and Kim, Kang Ho and Shneider, Benjamin L and Picarsic, Jennifer L and Jacobson, Theodora A and Zhang, Jing and He, Weimin and Liu, Pengfei and Knisely, A S and Finegold, Milton J and Muzny, Donna M and Boerwinkle, Eric and Lupski, James R and Plon, Sharon E and Gibbs, Richard A and Eng, Christine M and Yang, Yaping and Washington, Gabriel C and Porteus, Matthew H and Berquist, William E and Kambham, Neeraja and Singh, Ravinder J and Xia, Fan and Enns, Gregory M and Moore, David D} } @article {260, title = {Mutations in TJP2 cause progressive cholestatic liver disease.}, journal = {Nat Genet}, volume = {46}, year = {2014}, month = {2014 Apr}, pages = {326-8}, abstract = {

Elucidating genetic causes of cholestasis has proved to be important in understanding the physiology and pathophysiology of the liver. Here we show that protein-truncating mutations in the tight junction protein 2 gene (TJP2) cause failure of protein localization and disruption of tight-junction structure, leading to severe cholestatic liver disease. These findings contrast with those in the embryonic-lethal knockout mouse, highlighting differences in redundancy in junctional complexes between organs and species.

}, keywords = {Animals, Base Sequence, Cholestasis, Intrahepatic, High-Throughput Nucleotide Sequencing, Humans, Immunoblotting, Immunohistochemistry, Mice, Mice, Knockout, Microscopy, Electron, Transmission, Models, Biological, Molecular Sequence Data, Mutation, Pedigree, Real-Time Polymerase Chain Reaction, Sequence Alignment, Species Specificity, Tight Junctions, Zonula Occludens-2 Protein}, issn = {1546-1718}, doi = {10.1038/ng.2918}, author = {Sambrotta, Melissa and Strautnieks, Sandra and Papouli, Efterpi and Rushton, Peter and Clark, Barnaby E and Parry, David A and Logan, Clare V and Newbury, Lucy J and Kamath, Binita M and Ling, Simon and Grammatikopoulos, Tassos and Wagner, Bart E and Magee, John C and Sokol, Ronald J and Mieli-Vergani, Giorgina and Smith, Joshua D and Johnson, Colin A and McClean, Patricia and Simpson, Michael A and Knisely, A S and Bull, Laura N and Thompson, Richard J} }