@article {637, title = {Clinically severe CACNA1A alleles affect synaptic function and neurodegeneration differentially.}, journal = {PLoS Genet}, volume = {13}, year = {2017}, month = {2017 Jul}, pages = {e1006905}, abstract = {

Dominant mutations in CACNA1A, encoding the α-1A subunit of the neuronal P/Q type voltage-dependent Ca2+ channel, can cause diverse neurological phenotypes. Rare cases of markedly severe early onset developmental delay and congenital ataxia can be due to de novo CACNA1A missense alleles, with variants affecting the S4 transmembrane segments of the channel, some of which are reported to be loss-of-function. Exome sequencing in five individuals with severe early onset ataxia identified one novel variant (p.R1673P), in a girl with global developmental delay and progressive cerebellar atrophy, and a recurrent, de novo p.R1664Q variant, in four individuals with global developmental delay, hypotonia, and ophthalmologic abnormalities. Given the severity of these phenotypes we explored their functional impact in Drosophila. We previously generated null and partial loss-of-function alleles of cac, the homolog of CACNA1A in Drosophila. Here, we created transgenic wild type and mutant genomic rescue constructs with the two noted conserved point mutations. The p.R1673P mutant failed to rescue cac lethality, displayed a gain-of-function phenotype in electroretinograms (ERG) recorded from mutant clones, and evolved a neurodegenerative phenotype in aging flies, based on ERGs and transmission electron microscopy. In contrast, the p.R1664Q variant exhibited loss of function and failed to develop a neurodegenerative phenotype. Hence, the novel R1673P allele produces neurodegenerative phenotypes in flies and human, likely due to a toxic gain of function.

}, keywords = {Alleles, Animals, Animals, Genetically Modified, Calcium Channels, Cerebellar Ataxia, Child, Child, Preschool, Drosophila melanogaster, Female, Genome, Human, Genome-Wide Association Study, Humans, Male, Microscopy, Electron, Transmission, Mutation, Missense, Neurodegenerative Diseases, Neuroimaging, Phenotype, Point Mutation}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1006905}, author = {Luo, Xi and Rosenfeld, Jill A and Yamamoto, Shinya and Harel, Tamar and Zuo, Zhongyuan and Hall, Melissa and Wierenga, Klaas J and Pastore, Matthew T and Bartholomew, Dennis and Delgado, Mauricio R and Rotenberg, Joshua and Lewis, Richard Alan and Emrick, Lisa and Bacino, Carlos A and Eldomery, Mohammad K and Coban Akdemir, Zeynep and Xia, Fan and Yang, Yaping and Lalani, Seema R and Lotze, Timothy and Lupski, James R and Lee, Brendan and Bellen, Hugo J and Wangler, Michael F} } @article {262, title = {Laterality defects other than situs inversus totalis in primary ciliary dyskinesia: insights into situs ambiguus and heterotaxy.}, journal = {Chest}, volume = {146}, year = {2014}, month = {2014 Nov}, pages = {1176-1186}, abstract = {

BACKGROUND: Motile cilia dysfunction causes primary ciliary dyskinesia (PCD), situs inversus totalis (SI), and a spectrum of laterality defects, yet the prevalence of laterality defects other than SI in PCD has not been prospectively studied.

METHODS: In this prospective study, participants with suspected PCD were referred to our multisite consortium. We measured nasal nitric oxide (nNO) level, examined cilia with electron microscopy, and analyzed PCD-causing gene mutations. Situs was classified as (1) situs solitus (SS), (2) SI, or (3) situs ambiguus (SA), including heterotaxy. Participants with hallmark electron microscopic defects, biallelic gene mutations, or both were considered to have classic PCD.

RESULTS: Of 767 participants (median age, 8.1 years, range, 0.1-58 years), classic PCD was defined in 305, including 143 (46.9\%), 125 (41.0\%), and 37 (12.1\%) with SS, SI, and SA, respectively. A spectrum of laterality defects was identified with classic PCD, including 2.6\% and 2.3\% with SA plus complex or simple cardiac defects, respectively; 4.6\% with SA but no cardiac defect; and 2.6\% with an isolated possible laterality defect. Participants with SA and classic PCD had a higher prevalence of PCD-associated respiratory symptoms vs SA control participants (year-round wet cough, P < .001; year-round nasal congestion, P = .015; neonatal respiratory distress, P = .009; digital clubbing, P = .021) and lower nNO levels (median, 12 nL/min vs 252 nL/min; P < .001).

CONCLUSIONS: At least 12.1\% of patients with classic PCD have SA and laterality defects ranging from classic heterotaxy to subtle laterality defects. Specific clinical features of PCD and low nNO levels help to identify PCD in patients with laterality defects.

TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00323167; URL: www.clinicaltrials.gov.

}, keywords = {Adolescent, Adult, Biopsy, Child, Child, Preschool, Cilia, DNA, DNA Mutational Analysis, Female, Humans, Infant, Infant, Newborn, Kartagener Syndrome, Male, Microscopy, Electron, Transmission, Middle Aged, Mutation, Prevalence, Prospective Studies, Tomography, X-Ray Computed, United States, Young Adult}, issn = {1931-3543}, doi = {10.1378/chest.13-1704}, author = {Shapiro, Adam J and Davis, Stephanie D and Ferkol, Thomas and Dell, Sharon D and Rosenfeld, Margaret and Olivier, Kenneth N and Sagel, Scott D and Milla, Carlos and Zariwala, Maimoona A and Wolf, Whitney and Carson, Johnny L and Hazucha, Milan J and Burns, Kimberlie and Robinson, Blair and Knowles, Michael R and Leigh, Margaret W} } @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} }