@article {957, title = {Multiomic analysis elucidates Complex I deficiency caused by a deep intronic variant in NDUFB10.}, journal = {Hum Mutat}, volume = {42}, year = {2021}, month = {2021 Jan}, pages = {19-24}, abstract = {

The diagnosis of Mendelian disorders following uninformative exome and genome sequencing remains a challenging and often unmet need. Following uninformative exome and genome sequencing of a family quartet including two siblings with suspected mitochondrial disorder, RNA sequencing (RNAseq) was pursued in one sibling. Long-read amplicon sequencing was used to determine and quantify transcript structure. Immunoblotting studies and quantitative proteomics were performed to demonstrate functional impact. Differential expression analysis of RNAseq data identified significantly decreased expression of the mitochondrial OXPHOS Complex I subunit NDUFB10 associated with a cryptic exon in intron 1 of NDUFB10, that included an in-frame stop codon. The cryptic exon contained a rare intronic variant that was homozygous in both affected siblings. Immunoblot and quantitative proteomic analysis of fibroblasts revealed decreased abundance of Complex I subunits, providing evidence of isolated Complex I deficiency. Through multiomic analysis we present data implicating a deep intronic variant in NDUFB10 as the cause of mitochondrial disease in two individuals, providing further support of the gene-disease association. This study highlights the importance of transcriptomic and proteomic analyses as complementary diagnostic tools in patients undergoing genome-wide diagnostic evaluation.

}, issn = {1098-1004}, doi = {10.1002/humu.24135}, author = {Helman, Guy and Compton, Alison G and Hock, Daniella H and Walkiewicz, Marzena and Brett, Gemma R and Pais, Lynn and Tan, Tiong Y and De Paoli-Iseppi, Ricardo and Clark, Michael B and Christodoulou, John and White, Susan M and Thorburn, David R and Stroud, David A and Stark, Zornitza and Simons, Cas} } @article {968, title = {Evaluating systematic reanalysis of clinical genomic data in rare disease from single center experience and literature review.}, journal = {Mol Genet Genomic Med}, volume = {8}, year = {2020}, month = {2020 11}, pages = {e1508}, abstract = {

BACKGROUND: Our primary aim was to evaluate the systematic reanalysis of singleton exome sequencing (ES) data for unsolved cases referred for any indication. A secondary objective was to undertake a literature review of studies examining the reanalysis of genomic data from unsolved cases.

METHODS: We examined data from 58 unsolved cases referred between June 2016 and March 2017. First reanalysis at 4-13~months after the initial report considered genes newly associated with disease since the original analysis; second reanalysis at 9-18~months considered all disease-associated genes. At 25-34~months we reviewed all cases and the strategies which solved them.

RESULTS: Reanalysis of existing ES data alone at two timepoints did not yield new diagnoses. Over the same timeframe, 10 new diagnoses were obtained (17\%) from additional strategies, such as microarray detection of copy number variation, repeat sequencing to improve coverage, and trio sequencing. Twenty-seven peer-reviewed articles were identified on the literature review, with a median new diagnosis rate via reanalysis of 15\% and median reanalysis timeframe of 22~months.

CONCLUSION: Our findings suggest that an interval of greater than 18~months from the original report may be optimal for reanalysis. We also recommend a multi-faceted strategy for cases remaining unsolved after singleton ES.

}, issn = {2324-9269}, doi = {10.1002/mgg3.1508}, author = {Tan, Natalie B and Stapleton, Rachel and Stark, Zornitza and Delatycki, Martin B and Yeung, Alison and Hunter, Matthew F and Amor, David J and Brown, Natasha J and Stutterd, Chloe A and McGillivray, George and Yap, Patrick and Regan, Matthew and Chong, Belinda and Fanjul Fernandez, Miriam and Marum, Justine and Phelan, Dean and Pais, Lynn S and White, Susan M and Lunke, Sebastian and Tan, Tiong Y} } @article {770, title = {MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.}, journal = {Brain}, volume = {143}, year = {2020}, month = {2020 01 01}, pages = {55-68}, abstract = {

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3{\textquoteright} region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.

}, keywords = {Abnormalities, Multiple, Adolescent, Basilar Artery, Carotid Arteries, Cerebellar Vermis, Cerebellum, Child, Child, Preschool, Cohort Studies, Comparative Genomic Hybridization, Craniofacial Abnormalities, Female, Fibroblasts, Humans, Imaging, Three-Dimensional, Infant, Intellectual Disability, Language Development Disorders, Magnetic Resonance Imaging, Male, Middle Aged, Mutation, Nervous System Malformations, Nonsense Mediated mRNA Decay, Polymicrogyria, Real-Time Polymerase Chain Reaction, RNA-Seq, Syndrome, Tomography, X-Ray Computed, Trans-Activators, Tumor Suppressor Proteins, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1460-2156}, doi = {10.1093/brain/awz379}, author = {Mak, Christopher C Y and Doherty, Dan and Lin, Angela E and Vegas, Nancy and Cho, Megan T and Viot, G{\'e}raldine and Dimartino, Cl{\'e}mantine and Weisfeld-Adams, James D and Lessel, Davor and Joss, Shelagh and Li, Chumei and Gonzaga-Jauregui, Claudia and Zarate, Yuri A and Ehmke, Nadja and Horn, Denise and Troyer, Caitlin and Kant, Sarina G and Lee, Youngha and Ishak, Gisele E and Leung, Gordon and Barone Pritchard, Amanda and Yang, Sandra and Bend, Eric G and Filippini, Francesca and Roadhouse, Chelsea and Lebrun, Nicolas and Mehaffey, Michele G and Martin, Pierre-Marie and Apple, Benjamin and Millan, Francisca and Puk, Oliver and Hoffer, Mariette J V and Henderson, Lindsay B and McGowan, Ruth and Wentzensen, Ingrid M and Pei, Steven and Zahir, Farah R and Yu, Mullin and Gibson, William T and Seman, Ann and Steeves, Marcie and Murrell, Jill R and Luettgen, Sabine and Francisco, Elizabeth and Strom, Tim M and Amlie-Wolf, Louise and Kaindl, Angela M and Wilson, William G and Halbach, Sara and Basel-Salmon, Lina and Lev-El, Noa and Denecke, Jonas and Vissers, Lisenka E L M and Radtke, Kelly and Chelly, Jamel and Zackai, Elaine and Friedman, Jan M and Bamshad, Michael J and Nickerson, Deborah A and Reid, Russell R and Devriendt, Koenraad and Chae, Jong-Hee and Stolerman, Elliot and McDougall, Carey and Powis, Z{\"o}e and Bienvenu, Thierry and Tan, Tiong Y and Orenstein, Naama and Dobyns, William B and Shieh, Joseph T and Choi, Murim and Waggoner, Darrel and Gripp, Karen W and Parker, Michael J and Stoler, Joan and Lyonnet, Stanislas and Cormier-Daire, Val{\'e}rie and Viskochil, David and Hoffman, Trevor L and Amiel, Jeanne and Chung, Brian H Y and Gordon, Christopher T} } @article {912, title = {Phenotypic spectrum and transcriptomic profile associated with germline variants in TRAF7.}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 07}, pages = {1215-1226}, abstract = {

PURPOSE: Somatic variants in tumor necrosis factor receptor-associated factor 7 (TRAF7) cause meningioma, while germline variants have recently been identified in seven patients with developmental delay and cardiac, facial, and digital anomalies. We aimed to define the clinical and mutational spectrum associated with TRAF7 germline variants in a large series of patients, and to determine the molecular effects of the variants through transcriptomic analysis of patient fibroblasts.

METHODS: We performed exome, targeted capture, and Sanger sequencing of patients with undiagnosed developmental disorders, in multiple independent diagnostic or research centers. Phenotypic and mutational comparisons were facilitated through data exchange platforms. Whole-transcriptome sequencing was performed on RNA from patient- and control-derived fibroblasts.

RESULTS: We identified heterozygous missense variants in TRAF7 as the cause of a developmental delay-malformation syndrome in 45 patients. Major features include a recognizable facial gestalt (characterized in particular by blepharophimosis), short neck, pectus carinatum, digital deviations, and patent ductus arteriosus. Almost all variants occur in the WD40 repeats and most are recurrent. Several differentially expressed genes were identified in patient fibroblasts.

CONCLUSION: We provide the first large-scale analysis of the clinical and mutational spectrum associated with the TRAF7 developmental syndrome, and we shed light on its molecular etiology through transcriptome studies.

}, keywords = {Exome, Germ Cells, Humans, Intellectual Disability, Mutation, Missense, Phenotype, Transcriptome, Tumor Necrosis Factor Receptor-Associated Peptides and Proteins}, issn = {1530-0366}, doi = {10.1038/s41436-020-0792-7}, author = {Castilla-Vallmanya, Laura and Selmer, Kaja K and Dimartino, Cl{\'e}mantine and Rabionet, Raquel and Blanco-S{\'a}nchez, Bernardo and Yang, Sandra and Reijnders, Margot R F and van Essen, Antonie J and Oufadem, Myriam and Vigeland, Magnus D and Stadheim, Barbro and Houge, Gunnar and Cox, Helen and Kingston, Helen and Clayton-Smith, Jill and Innis, Jeffrey W and Iascone, Maria and Cereda, Anna and Gabbiadini, Sara and Chung, Wendy K and Sanders, Victoria and Charrow, Joel and Bryant, Emily and Millichap, John and Vitobello, Antonio and Thauvin, Christel and Mau-Them, Frederic Tran and Faivre, Laurence and Lesca, Gaetan and Labalme, Audrey and Rougeot, Christelle and Chatron, Nicolas and Sanlaville, Damien and Christensen, Katherine M and Kirby, Amelia and Lewandowski, Raymond and Gannaway, Rachel and Aly, MAH and Lehman, Anna and Clarke, Lorne and Graul-Neumann, Luitgard and Zweier, Christiane and Lessel, Davor and Lozic, Bernarda and Aukrust, Ingvild and Peretz, Ryan and Stratton, Robert and Smol, Thomas and Dieux-Co{\"e}slier, Anne and Meira, Joanna and Wohler, Elizabeth and Sobreira, Nara and Beaver, Erin M and Heeley, Jennifer and Briere, Lauren C and High, Frances A and Sweetser, David A and Walker, Melissa A and Keegan, Catherine E and Jayakar, Parul and Shinawi, Marwan and Kerstjens-Frederikse, Wilhelmina S and Earl, Dawn L and Siu, Victoria M and Reesor, Emma and Yao, Tony and Hegele, Robert A and Vaske, Olena M and Rego, Shannon and Shapiro, Kevin A and Wong, Brian and Gambello, Michael J and McDonald, Marie and Karlowicz, Danielle and Colombo, Roberto and Serretti, Alessandro and Pais, Lynn and O{\textquoteright}Donnell-Luria, Anne and Wray, Alison and Sadedin, Simon and Chong, Belinda and Tan, Tiong Y and Christodoulou, John and White, Susan M and Slavotinek, Anne and Barbouth, Deborah and Morel Swols, Dayna and Parisot, M{\'e}lanie and Bole-Feysot, Christine and Nitschk{\'e}, Patrick and Pingault, V{\'e}ronique and Munnich, Arnold and Cho, Megan T and Cormier-Daire, Val{\'e}rie and Balcells, Susanna and Lyonnet, Stanislas and Grinberg, Daniel and Amiel, Jeanne and Urreizti, Roser and Gordon, Christopher T} } @article {582, title = {Cerebral hypomyelination associated with biallelic variants of FIG4.}, journal = {Hum Mutat}, volume = {40}, year = {2019}, month = {2019 05}, pages = {619-630}, abstract = {

The lipid phosphatase gene FIG4 is responsible for Yunis-Var{\'o}n syndrome and Charcot-Marie-Tooth disease Type 4J, a peripheral neuropathy. We now describe four families with FIG4 variants and prominent abnormalities of central nervous system (CNS) white matter (leukoencephalopathy), with onset in early childhood, ranging from severe hypomyelination to mild undermyelination, in addition to peripheral neuropathy. Affected individuals inherited biallelic FIG4 variants from heterozygous parents. Cultured fibroblasts exhibit enlarged vacuoles characteristic of FIG4 dysfunction. Two unrelated families segregate the same G > A variant in the +1 position of intron 21 in the homozygous state in one family and compound heterozygous in the other. This mutation in the splice donor site of exon 21 results in read-through from exon 20 into intron 20 and truncation of the final 115 C-terminal amino acids of FIG4, with retention of partial function. The observed CNS white matter disorder in these families is consistent with the myelination defects in the FIG4 null mouse and the known role of FIG4 in oligodendrocyte maturation. The families described here the expanded clinical spectrum of FIG4 deficiency to include leukoencephalopathy.

}, issn = {1098-1004}, doi = {10.1002/humu.23720}, author = {Lenk, Guy M and Berry, Ian R and Stutterd, Chloe A and Blyth, Moira and Green, Lydia and Vadlamani, Gayatri and Warren, Daniel and Craven, Ian and Fanjul-Fernandez, Miriam and Rodriguez-Casero, Victoria and Lockhart, Paul J and Vanderver, Adeline and Simons, Cas and Gibb, Susan and Sadedin, Simon and White, Susan M and Christodoulou, John and Skibina, Olga and Ruddle, Jonathan and Tan, Tiong Y and Leventer, Richard J and Livingston, John H and Meisler, Miriam H} } @article {709, title = {Clinical Spectrum and Functional Consequences Associated with Bi-Allelic Pathogenic Variants.}, journal = {J Clin Med}, volume = {8}, year = {2019}, month = {2019 Nov 19}, abstract = {

(PNPase-polynucleotide phosphorylase) is involved in multiple RNA processing functions in the mitochondria. Bi-allelic pathogenic variants cause heterogeneous clinical phenotypes affecting multiple organs without any established genotype-phenotype correlations. Defects in PNPase can cause variable combined respiratory chain complex defects. Recently, it has been suggested that PNPase can lead to activation of an innate immune response. To better understand the clinical and molecular spectrum of patients with bi-allelic variants, we captured detailed clinical and molecular phenotypes of all 17 patients reported in the literature, plus seven new patients, including a 78-year-old male with the longest reported survival. A functional follow-up of genomic sequencing by cDNA studies confirmed a splicing defect in a novel, apparently synonymous, variant. Patient fibroblasts showed an accumulation of mitochondrial unprocessed transcripts, while blood showed an increased interferon response. Our findings suggest that functional analyses of the RNA processing function of PNPase are more sensitive than testing downstream defects in oxidative phosphorylation (OXPHPOS) enzyme activities. This research extends our knowledge of the clinical and functional consequences of bi-allelic pathogenic variants that may guide management and further efforts into understanding the pathophysiological mechanisms for therapeutic development.

}, issn = {2077-0383}, doi = {10.3390/jcm8112020}, author = {Rius, Rocio and Van Bergen, Nicole J and Compton, Alison G and Riley, Lisa G and Kava, Maina P and Balasubramaniam, Shanti and Amor, David J and Fanjul-Fernandez, Miriam and Cowley, Mark J and Fahey, Michael C and Koenig, Mary K and Enns, Gregory M and Sadedin, Simon and Wilson, Meredith J and Tan, Tiong Y and Thorburn, David R and Christodoulou, John} }