@article {586, title = {Contribution of noncoding pathogenic variants to RPGRIP1-mediated inherited retinal degeneration.}, journal = {Genet Med}, volume = {21}, year = {2019}, month = {2019 03}, pages = {694-704}, abstract = {

PURPOSE: With the advent of gene therapies for inherited retinal degenerations (IRDs), genetic diagnostics will have an increasing role in clinical decision-making. Yet the genetic cause of disease cannot be identified using exon-based sequencing for a significant portion of patients. We hypothesized that noncoding pathogenic variants contribute significantly to the genetic causality of IRDs and evaluated patients with single coding pathogenic variants in RPGRIP1 to test this hypothesis.

METHODS: IRD families underwent targeted panel sequencing. Unsolved cases were explored by exome and genome sequencing looking for additional pathogenic variants. Candidate pathogenic variants were then validated by Sanger sequencing, quantitative polymerase chain reaction, and in vitro splicing assays in two cell lines analyzed through amplicon sequencing.

RESULTS: Among 1722 families, 3 had biallelic loss-of-function pathogenic variants in RPGRIP1 while 7 had a single disruptive coding pathogenic variants. Exome and genome sequencing revealed potential noncoding pathogenic variants in these 7 families. In 6, the noncoding pathogenic variants were shown to lead to loss of function in vitro.

CONCLUSION: Noncoding pathogenic variants were identified in 6 of 7 families with single coding pathogenic variants in RPGRIP1. The results suggest that noncoding pathogenic variants contribute significantly to the genetic causality of IRDs and RPGRIP1-mediated IRDs are more common than previously thought.

}, keywords = {Adult, Chromosome Mapping, DNA Mutational Analysis, DNA, Intergenic, Female, HEK293 Cells, Humans, Male, Mutation, Pedigree, Proteins, Retinal Degeneration, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-018-0104-7}, author = {Jamshidi, Farzad and Place, Emily M and Mehrotra, Sudeep and Navarro-Gomez, Daniel and Maher, Mathew and Branham, Kari E and Valkanas, Elise and Cherry, Timothy J and Lek, Monkol and Macarthur, Daniel and Pierce, Eric A and Bujakowska, Kinga M} } @article {447, title = {A noncoding variant in GANAB explains isolated polycystic liver disease (PCLD) in a large family.}, journal = {Hum Mutat}, volume = {39}, year = {2018}, month = {2018 03}, pages = {378-382}, abstract = {

Expanded mutation detection and novel gene discovery for isolated polycystic liver disease (PCLD) are necessary as 50\% of cases do not have identified mutations in the seven published disease genes. We investigated a family with five affected siblings for which no loss-of-function variants were identified by whole exome sequencing analysis. SNP genotyping and linkage analysis narrowed the candidate regions to \~{}8\% of the genome, which included two published PCLD genes in close proximity to each other, GANAB and LRP5. Based on these findings, we re-evaluated the exome sequencing data and identified a novel intronic nine base pair deletion in the vicinity of the GANAB exon 24 splice donor that had initially been discarded by the sequence analysis pipelines. We used a minigene assay to show that this deletion leads to skipping of exon 24 in cell lines and primary human cholangiocytes. These findings prompt genomic evaluation beyond the coding region to enhance mutation detection in PCLD and to avoid premature implication of other genes in linkage disequilibrium.

}, keywords = {Base Sequence, Cysts, DNA, Intergenic, Evolution, Molecular, Exons, Glucosidases, Humans, Liver Diseases, Low Density Lipoprotein Receptor-Related Protein-5, Mutation}, issn = {1098-1004}, doi = {10.1002/humu.23383}, author = {Besse, Whitney and Choi, Jungmin and Ahram, Dina and Mane, Shrikant and Sanna-Cherchi, Simone and Torres, Vicente and Somlo, Stefan} }