@article {354, title = {Loss of carbonic anhydrase XII function in individuals with elevated sweat chloride concentration and pulmonary airway disease.}, journal = {Hum Mol Genet}, volume = {25}, year = {2016}, month = {2016 05 15}, pages = {1923-1933}, abstract = {

Elevated sweat chloride levels, failure to thrive (FTT), and lung disease are characteristic features of cystic fibrosis (CF, OMIM $\#$219700). Here we describe variants in CA12 encoding carbonic anhydrase XII in two pedigrees exhibiting CF-like phenotypes. Exome sequencing of a white American adult diagnosed with CF due to elevated sweat chloride, recurrent hyponatremia, infantile FTT and lung disease identified deleterious variants in each CA12 gene: c.908-1 G>A in a splice acceptor and a novel frameshift insertion c.859_860insACCT. In an unrelated consanguineous Omani family, two children with elevated sweat chloride, infantile FTT, and recurrent hyponatremia were homozygous for a novel missense variant (p.His121Gln). Deleterious CFTR variants were absent in both pedigrees. CA XII protein was localized apically in human bronchiolar epithelia and basolaterally in the reabsorptive duct of human sweat glands. Respiratory epithelial cell RNA from the adult proband revealed only aberrant CA12 transcripts and in vitro analysis showed greatly reduced CA XII protein. Studies of ion transport across respiratory epithelial cells in vivo and in culture revealed intact CFTR-mediated chloride transport in the adult proband. CA XII protein bearing either p.His121Gln or a previously identified p.Glu143Lys missense variant localized to the basolateral membranes of polarized Madin-Darby canine kidney (MDCK) cells, but enzyme activity was severely diminished when assayed at physiologic concentrations of extracellular chloride. Our findings indicate that loss of CA XII function should be considered in individuals without CFTR mutations who exhibit CF-like features in the sweat gland and lung.

}, keywords = {Adolescent, Adult, Animals, Carbonic Anhydrases, Child, Child, Preschool, Chlorides, Cystic Fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator, Dogs, Female, Gene Expression Regulation, Enzymologic, Homozygote, Humans, Lung, Lung Diseases, Madin Darby Canine Kidney Cells, Male, Mutation, Pedigree, Phenotype, Sweat}, issn = {1460-2083}, doi = {10.1093/hmg/ddw065}, author = {Lee, Melissa and Vecchio-Pag{\'a}n, Briana and Sharma, Neeraj and Waheed, Abdul and Li, Xiaopeng and Raraigh, Karen S and Robbins, Sarah and Han, Sangwoo T and Franca, Arianna L and Pellicore, Matthew J and Evans, Taylor A and Arcara, Kristin M and Nguyen, Hien and Luan, Shan and Belchis, Deborah and Hertecant, Jozef and Zabner, Joseph and Sly, William S and Cutting, Garry R} } @article {85, title = {Recurrent recessive mutation in deoxyguanosine kinase causes idiopathic noncirrhotic portal hypertension.}, journal = {Hepatology}, volume = {63}, year = {2016}, month = {2016 06}, pages = {1977-86}, abstract = {

UNLABELLED: Despite advances in the diagnosis and management of idiopathic noncirrhotic portal hypertension, its pathogenesis remains elusive. Insight may be gained from study of early-onset familial idiopathic noncirrhotic portal hypertension, in which Mendelian mutations may account for disease. We performed exome sequencing of eight subjects from six kindreds with onset of portal hypertension of indeterminate etiology during infancy or childhood. Three subjects from two consanguineous families shared the identical rare homozygous p.N46S mutation in DGUOK, a deoxyguanosine kinase required for mitochondrial DNA replication; haplotype sharing demonstrated that the mutation in the two families was inherited from a remote common ancestor. All three affected subjects had stable portal hypertension with noncirrhotic liver disease for 6-16 years of follow-up. This mutation impairs adenosine triphosphate binding and reduces catalytic activity. Loss-of-function mutations in DGUOK have previously been implicated in cirrhosis and liver failure but not in isolated portal hypertension. Interestingly, treatment of patients with human immunodeficiency viral infection with the nucleoside analogue didanosine is known to cause portal hypertension in a subset of patients and lowers deoxyguanosine kinase levels in vitro; the current findings implicate these effects on deoxyguanosine kinase in the causal mechanism.

CONCLUSION: Our findings provide new insight into the mechanisms mediating inherited and acquired noncirrhotic portal hypertension, expand the phenotypic spectrum of DGUOK deficiency, and provide a new genetic test for a specific cause of idiopathic noncirrhotic portal hypertension. (Hepatology 2016;63:1977-1986).

}, keywords = {Adolescent, Amino Acid Sequence, Animals, Cattle, Child, Child, Preschool, DNA Mutational Analysis, Dogs, Female, Genes, Recessive, Homozygote, Humans, Hypertension, Portal, Infant, Liver Failure, Male, Molecular Sequence Data, Pedigree, Phosphotransferases (Alcohol Group Acceptor), Principal Component Analysis, Rats, Young Adult}, issn = {1527-3350}, doi = {10.1002/hep.28499}, author = {Vilarinho, S{\'\i}lvia and Sari, Sinan and Yilmaz, G{\"u}ldal and Stiegler, Amy L and Boggon, Titus J and Jain, Dhanpat and Akyol, G{\"u}len and Dalgi{\c c}, Buket and G{\"u}nel, Murat and Lifton, Richard P} }