@article {371, title = {Activation of a cryptic splice site in the mitochondrial elongation factor GFM1 causes combined OXPHOS deficiency.}, journal = {Mitochondrion}, volume = {34}, year = {2017}, month = {2017 05}, pages = {84-90}, abstract = {

We report the clinical, biochemical, and molecular findings in two brothers with encephalopathy and multi-systemic disease. Abnormal transferrin glycoforms were suggestive of a type I congenital disorder of glycosylation (CDG). While exome sequencing was negative for CDG related candidate genes, the testing revealed compound heterozygous mutations in the mitochondrial elongation factor G gene (GFM1). One of the mutations had been reported previously while the second, novel variant was found deep in intron 6, activating a cryptic splice site. Functional studies demonstrated decreased GFM1 protein levels, suggested disrupted assembly of mitochondrial complexes III and V and decreased activities of mitochondrial complexes I and IV, all indicating combined OXPHOS deficiency.

}, keywords = {Child, Child, Preschool, Congenital Abnormalities, Gene Expression, Humans, Infant, Infant, Newborn, Male, Mitochondrial Proteins, Oxidative Phosphorylation, Peptide Elongation Factor G, RNA Splice Sites}, issn = {1872-8278}, doi = {10.1016/j.mito.2017.02.004}, author = {Simon, Mariella T and Ng, Bobby G and Friederich, Marisa W and Wang, Raymond Y and Boyer, Monica and Kircher, Martin and Collard, Renata and Buckingham, Kati J and Chang, Richard and Shendure, Jay and Nickerson, Deborah A and Bamshad, Michael J and Van Hove, Johan L K and Freeze, Hudson H and Abdenur, Jose E} } @article {381, title = {Encephalopathy caused by novel mutations in the CMP-sialic acid transporter, SLC35A1.}, journal = {Am J Med Genet A}, volume = {173}, year = {2017}, month = {2017 Nov}, pages = {2906-2911}, abstract = {

Transport of activated nucleotide-sugars into the Golgi is critical for proper glycosylation and mutations in these transporters cause a group of rare genetic disorders termed congenital disorders of glycosylation. We performed exome sequencing on an individual with a profound neurological presentation and identified rare compound heterozygous mutations, p.Thr156Arg and p.Glu196Lys, in the CMP-sialic acid transporter, SLC35A1. Patient primary fibroblasts and serum showed a considerable decrease in the amount of N- and O-glycans terminating in sialic acid. Direct measurement of CMP-sialic acid transport into the Golgi showed a substantial decrease in overall rate of transport. Here we report the identification of the third patient with CMP-sialic acid transporter deficiency, who presented with severe neurological phenotype, but without hematological abnormalities.

}, keywords = {Animals, Brain Diseases, Child, CHO Cells, Cricetinae, Cricetulus, Female, Flow Cytometry, Golgi Apparatus, Humans, Mutation, N-Acetylneuraminic Acid, Nucleotide Transport Proteins, Whole Exome Sequencing}, issn = {1552-4833}, doi = {10.1002/ajmg.a.38412}, author = {Ng, Bobby G and Asteggiano, Carla G and Kircher, Martin and Buckingham, Kati J and Raymond, Kimiyo and Nickerson, Deborah A and Shendure, Jay and Bamshad, Michael J and Ensslen, Matthias and Freeze, Hudson H} } @article {31, title = {SRD5A3-CDG: Expanding the phenotype of a congenital disorder of glycosylation with emphasis on adult onset features.}, journal = {Am J Med Genet A}, volume = {170}, year = {2016}, month = {2016 Dec}, pages = {3165-3171}, abstract = {

Increasing numbers of congenital disorders of glycosylation (CDG) have been reported recently resulting in an expansion of the phenotypes associated with this group of disorders. SRD5A3 codes for polyprenol reductase which converts polyprenol to dolichol. This is a major pathway for dolichol biosynthesis for N-glycosylation, O-mannosylation, C-mannosylation, and GPI anchor synthesis. We present the features of five individuals (three children and two adults) with mutations in SRD5A3 focusing on the variable eye and skin involvement. We compare that to 13 affected individuals from the literature including five adults allowing us to delineate the features that may develop over time with this disorder including kyphosis, retinitis pigmentosa, and cataracts. {\textcopyright} 2016 Wiley Periodicals, Inc.

}, keywords = {3-Oxo-5-alpha-Steroid 4-Dehydrogenase, Adult, Child, Congenital Disorders of Glycosylation, Dolichols, Eye, Female, Glycosylation, Homozygote, Humans, Male, Membrane Proteins, Mutation, Phenotype, Skin, Tretinoin}, issn = {1552-4833}, doi = {10.1002/ajmg.a.37875}, author = {Wheeler, Patricia G and Ng, Bobby G and Sanford, Laura and Sutton, V Reid and Bartholomew, Dennis W and Pastore, Matthew T and Bamshad, Michael J and Kircher, Martin and Buckingham, Kati J and Nickerson, Deborah A and Shendure, Jay and Freeze, Hudson H} } @article {305, title = {Mosaicism of the UDP-galactose transporter SLC35A2 causes a congenital disorder of glycosylation.}, journal = {Am J Hum Genet}, volume = {92}, year = {2013}, month = {2013 Apr 04}, pages = {632-6}, abstract = {

Biochemical analysis and whole-exome sequencing identified mutations in the Golgi-localized UDP-galactose transporter SLC35A2 that define an undiagnosed X-linked congenital disorder of glycosylation (CDG) in three unrelated families. Each mutation reduced UDP-galactose transport, leading to galactose-deficient glycoproteins. Two affected males were somatic mosaics, suggesting that a wild-type SLC35A2 allele may be required for survival. In infancy, the commonly used biomarker transferrin showed abnormal glycosylation, but its appearance became normal later in childhood, without any corresponding clinical improvement. This may indicate selection against cells carrying the mutant allele. To detect other individuals with such mutations, we suggest transferrin testing in infancy. Here, we report somatic mosaicism in CDG, and our work stresses the importance of combining both genetic and biochemical diagnoses.

}, keywords = {Biological Transport, Case-Control Studies, Child, Child, Preschool, Congenital Disorders of Glycosylation, Exome, Female, Glycosylation, Humans, Male, Monosaccharide Transport Proteins, Mosaicism, Mutation, Spectrometry, Mass, Electrospray Ionization, Transferrin, Uridine Diphosphate Galactose}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.03.012}, author = {Ng, Bobby G and Buckingham, Kati J and Raymond, Kimiyo and Kircher, Martin and Turner, Emily H and He, Miao and Smith, Joshua D and Eroshkin, Alexey and Szybowska, Marta and Losfeld, Marie E and Chong, Jessica X and Kozenko, Mariya and Li, Chumei and Patterson, Marc C and Gilbert, Rodney D and Nickerson, Deborah A and Shendure, Jay and Bamshad, Michael J and Freeze, Hudson H} }