@article {767, title = {Recurrent De Novo NAHR Reciprocal Duplications in the ATAD3 Gene Cluster Cause a Neurogenetic Trait with Perturbed Cholesterol and Mitochondrial Metabolism.}, journal = {Am J Hum Genet}, volume = {106}, year = {2020}, month = {2020 02 06}, pages = {272-279}, abstract = {

Recent studies have identified both recessive and dominant forms of mitochondrial disease that result from ATAD3A variants. The recessive form includes subjects with biallelic deletions mediated by non-allelic homologous recombination. We report five unrelated neonates with a lethal metabolic disorder characterized by cardiomyopathy, corneal opacities, encephalopathy, hypotonia, and seizures in whom a monoallelic reciprocal duplication at the ATAD3 locus was identified. Analysis of the breakpoint junction fragment indicated that these 67 kb heterozygous duplications were likely mediated by non-allelic homologous recombination at regions of high sequence identity in ATAD3A exon 11 and ATAD3C exon 7. At the recombinant junction, the duplication allele produces a fusion gene derived from ATAD3A and ATAD3C, the protein product of which lacks key functional residues. Analysis of fibroblasts derived from two affected individuals shows that the fusion gene product is expressed and stable. These cells display perturbed cholesterol and mitochondrial DNA organization similar to that observed for individuals with severe ATAD3A deficiency. We hypothesize that the fusion protein acts through a dominant-negative mechanism to cause this fatal mitochondrial disorder. Our data delineate a molecular diagnosis for this disorder, extend the clinical spectrum associated with structural variation at the ATAD3 locus, and identify a third mutational mechanism for ATAD3 gene cluster variants. These results further affirm structural variant mutagenesis mechanisms in sporadic disease traits, emphasize the importance of copy number analysis in molecular genomic diagnosis, and highlight some of the challenges of detecting and interpreting clinically relevant rare gene rearrangements from next-generation sequencing data.

}, keywords = {Amino Acid Sequence, ATPases Associated with Diverse Cellular Activities, Brain Diseases, Cardiomyopathies, Cholesterol, Corneal Opacity, DNA Copy Number Variations, Female, Gene Duplication, Gene Rearrangement, Homologous Recombination, Humans, Infant, Infant, Newborn, Male, Membrane Proteins, Mitochondria, Mitochondrial Diseases, Mitochondrial Proteins, Muscle Hypotonia, Mutation, Protein Conformation, Seizures, Sequence Homology}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2020.01.007}, author = {Gunning, Adam C and Strucinska, Klaudia and Mu{\~n}oz Oreja, Mikel and Parrish, Andrew and Caswell, Richard and Stals, Karen L and Durigon, Romina and Durlacher-Betzer, Karina and Cunningham, Mitchell H and Grochowski, Christopher M and Baptista, Julia and Tysoe, Carolyn and Baple, Emma and Lahiri, Nayana and Homfray, Tessa and Scurr, Ingrid and Armstrong, Catherine and Dean, John and Fernandez Pelayo, Uxoa and Jones, Aleck W E and Taylor, Robert W and Misra, Vinod K and Yoon, Wan Hee and Wright, Caroline F and Lupski, James R and Spinazzola, Antonella and Harel, Tamar and Holt, Ian J and Ellard, Sian} } @article {223, title = {NGLY1 mutation causes neuromotor impairment, intellectual disability, and neuropathy.}, journal = {Eur J Med Genet}, volume = {58}, year = {2015}, month = {2015 Jan}, pages = {39-43}, abstract = {

N-glycanase 1 (NGLY1) is a conserved enzyme that is responsible for the deglycosylation of misfolded N-glycosylated proteins in the cytoplasm prior to their proteasome-mediated degradation. Disruption of this degradation process has been associated with various neurologic diseases including amyotrophic lateral sclerosis and Parkinson{\textquoteright}s disease. Here, we describe two siblings with neuromotor impairment, apparent intellectual disability, corneal opacities, and neuropathy who were found to possess a novel homozygous frame-shift mutation due to a 4 base pair deletion in NGLY1 (c.1533_1536delTCAA, p.Asn511LysfsX51). We hypothesize that this mutation likely limits the capability of neuronal cells to respond to stress due to accumulation of misfolded proteins, thereby impairing their survival and resulting in progressive loss of neurological function.

}, keywords = {Abnormalities, Multiple, Adolescent, Child, Corneal Opacity, Developmental Disabilities, Female, Frameshift Mutation, Genotype, Humans, Intellectual Disability, Male, Movement Disorders, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase, Peripheral Nervous System Diseases}, issn = {1878-0849}, doi = {10.1016/j.ejmg.2014.08.008}, author = {{\c C}a{\u g}layan, Ahmet Okay and Comu, Sinan and Baranoski, Jacob F and Parman, Yesim and Kaymak{\c c}alan, Hande and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Caglar, Caner and D{\"o}len, Duygu and Erson-Omay, Emine Zeynep and Harmanci, Akdes Serin and Mishra-Gorur, Ketu and Freeze, Hudson H and Yasuno, Katsuhito and Bilguvar, Kaya and G{\"u}nel, Murat} } @article {243, title = {Monoallelic and biallelic mutations in MAB21L2 cause a spectrum of major eye malformations.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 Jun 05}, pages = {915-23}, abstract = {

We identified four different missense mutations in the single-exon gene MAB21L2 in eight individuals with bilateral eye malformations from five unrelated families via three independent exome sequencing projects. Three mutational events altered the same amino acid (Arg51), and two were identical de novo mutations (c.151C>T [p.Arg51Cys]) in unrelated children with bilateral anophthalmia, intellectual disability, and rhizomelic skeletal dysplasia. c.152G>A (p.Arg51His) segregated with autosomal-dominant bilateral colobomatous microphthalmia in a large multiplex family. The fourth heterozygous mutation (c.145G>A [p.Glu49Lys]) affected an amino acid within two residues of Arg51 in an adult male with bilateral colobomata. In a fifth family, a homozygous mutation (c.740G>A [p.Arg247Gln]) altering a different region of the protein was identified in two male siblings with bilateral retinal colobomata. In mouse embryos, Mab21l2 showed strong expression in the developing eye, pharyngeal arches, and limb bud. As predicted by structural homology, wild-type MAB21L2 bound single-stranded RNA, whereas this activity was lost in all altered forms of the protein. MAB21L2 had no detectable nucleotidyltransferase activity in~vitro, and its function remains unknown. Induced expression of wild-type MAB21L2 in human embryonic kidney 293 cells increased phospho-ERK (pERK1/2) signaling. Compared to the wild-type and p.Arg247Gln proteins, the proteins with the Glu49 and Arg51 variants had increased stability. Abnormal persistence of pERK1/2 signaling in MAB21L2-expressing cells during development is a plausible pathogenic mechanism for the heterozygous mutations. The phenotype associated with the homozygous mutation might be a consequence of complete loss of MAB21L2 RNA binding, although the cellular function of this interaction remains unknown.

}, keywords = {Adult, Alleles, Animals, Anophthalmos, Brain Diseases, Metabolic, Inborn, Coloboma, Corneal Opacity, Exome, Eye Proteins, Female, Gene Expression, HEK293 Cells, Heterozygote, Homozygote, Humans, Intellectual Disability, Intracellular Signaling Peptides and Proteins, Male, Mice, Microcephaly, Microphthalmos, Mutation, Missense, Pedigree, Phenotype, Protein Conformation, Signal Transduction}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.05.005}, author = {Rainger, Joe and Pehlivan, Davut and Johansson, Stefan and Bengani, Hemant and Sanchez-Pulido, Luis and Williamson, Kathleen A and Ture, Mehmet and Barker, Heather and Rosendahl, Karen and Spranger, J{\"u}rgen and Horn, Denise and Meynert, Alison and Floyd, James A B and Prescott, Trine and Anderson, Carl A and Rainger, Jacqueline K and Karaca, Ender and Gonzaga-Jauregui, Claudia and Jhangiani, Shalini and Muzny, Donna M and Seawright, Anne and Soares, Dinesh C and Kharbanda, Mira and Murday, Victoria and Finch, Andrew and Gibbs, Richard A and van Heyningen, Veronica and Taylor, Martin S and Yakut, Tahsin and Knappskog, Per M and Hurles, Matthew E and Ponting, Chris P and Lupski, James R and Houge, Gunnar and FitzPatrick, David R} }