@article {815, title = {Predominant and novel de novo variants in 29 individuals with ALG13 deficiency: Clinical description, biomarker status, biochemical analysis, and treatment suggestions.}, journal = {J Inherit Metab Dis}, volume = {43}, year = {2020}, month = {2020 11}, pages = {1333-1348}, abstract = {

Asparagine-linked glycosylation 13 homolog (ALG13) encodes a nonredundant, highly conserved, X-linked uridine diphosphate (UDP)-N-acetylglucosaminyltransferase required for the synthesis of lipid linked oligosaccharide precursor and proper N-linked glycosylation. De novo variants in ALG13 underlie a form of early infantile epileptic encephalopathy known as EIEE36, but given its essential role in glycosylation, it is also considered a congenital disorder of glycosylation (CDG), ALG13-CDG. Twenty-four previously reported ALG13-CDG cases had de novo variants, but surprisingly, unlike most forms of CDG, ALG13-CDG did not show the anticipated glycosylation defects, typically detected by altered transferrin glycosylation. Structural homology modeling of two recurrent de novo variants, p.A81T and p.N107S, suggests both are likely to impact the function of ALG13. Using a corresponding ALG13-deficient yeast strain, we show that expressing yeast ALG13 with either of the highly conserved hotspot variants rescues the observed growth defect, but not its glycosylation abnormality. We present molecular and clinical data on 29 previously unreported individuals with de novo variants in ALG13. This more than doubles the number of known cases. A key finding is that a vast majority of the individuals presents with West syndrome, a feature shared with other CDG types. Among these, the initial epileptic spasms best responded to adrenocorticotropic hormone or prednisolone, while clobazam and felbamate showed promise for continued epilepsy treatment. A ketogenic diet seems to play an important role in the treatment of these individuals.

}, issn = {1573-2665}, doi = {10.1002/jimd.12290}, author = {Ng, Bobby G and Eklund, Erik A and Shiryaev, Sergey A and Dong, Yin Y and Abbott, Mary-Alice and Asteggiano, Carla and Bamshad, Michael J and Barr, Eileen and Bernstein, Jonathan A and Chelakkadan, Shabeed and Christodoulou, John and Chung, Wendy K and Ciliberto, Michael A and Cousin, Janice and Gardiner, Fiona and Ghosh, Suman and Graf, William D and Grunewald, Stephanie and Hammond, Katherine and Hauser, Natalie S and Hoganson, George E and Houck, Kimberly M and Kohler, Jennefer N and Morava, Eva and Larson, Austin A and Liu, Pengfei and Madathil, Sujana and McCormack, Colleen and Meeks, Naomi J L and Miller, Rebecca and Monaghan, Kristin G and Nickerson, Deborah A and Palculict, Timothy Blake and Papazoglu, Gabriela Magali and Pletcher, Beth A and Scheffer, Ingrid E and Schenone, Andrea Beatriz and Schnur, Rhonda E and Si, Yue and Rowe, Leah J and Serrano Russi, Alvaro H and Russo, Rossana Sanchez and Thabet, Farouq and Tuite, Allysa and Villanueva, Mar{\'\i}a Mercedes and Wang, Raymond Y and Webster, Richard I and Wilson, Dorcas and Zalan, Alice and Wolfe, Lynne A and Rosenfeld, Jill A and Rhodes, Lindsay and Freeze, Hudson H} } @article {451, title = {Congenital Titinopathy: Comprehensive characterization and pathogenic insights.}, journal = {Ann Neurol}, volume = {83}, year = {2018}, month = {2018 Jun}, pages = {1105-1124}, abstract = {

OBJECTIVE: Comprehensive clinical characterization of congenital titinopathy to facilitate diagnosis and management of this important emerging disorder.

METHODS: Using massively parallel sequencing we identified 30 patients from 27 families with 2 pathogenic nonsense, frameshift and/or splice site TTN mutations in trans. We then undertook a detailed analysis of the clinical, histopathological and imaging features of these patients.

RESULTS: All patients had prenatal or early onset hypotonia and/or congenital contractures. None had ophthalmoplegia. Scoliosis and respiratory insufficiency typically developed early and progressed rapidly, whereas limb weakness was often slowly progressive, and usually did not prevent independent walking. Cardiac involvement was present in 46\% of patients. Relatives of 2 patients had dilated cardiomyopathy. Creatine kinase levels were normal to moderately elevated. Increased fiber size variation, internalized nuclei and cores were common histopathological abnormalities. Cap-like regions, whorled or ring fibers, and mitochondrial accumulations were also observed. Muscle magnetic resonance imaging showed gluteal, hamstring and calf muscle involvement. Western blot analysis showed a near-normal sized titin protein in all samples. The presence of 2 mutations predicted to impact both N2BA and N2B cardiac isoforms appeared to be associated with greatest risk of cardiac involvement. One-third of patients had 1 mutation predicted to impact exons present in fetal skeletal muscle, but not included within the mature skeletal muscle isoform transcript. This strongly suggests developmental isoforms are involved in the pathogenesis of this congenital/early onset disorder.

INTERPRETATION: This detailed clinical reference dataset will greatly facilitate diagnostic confirmation and management of patients, and has provided important insights into disease pathogenesis. Ann Neurol 2018;83:1105-1124.

}, issn = {1531-8249}, doi = {10.1002/ana.25241}, author = {Oates, Emily C and Jones, Kristi J and Donkervoort, Sandra and Charlton, Amanda and Brammah, Susan and Smith, John E and Ware, James S and Yau, Kyle S and Swanson, Lindsay C and Whiffin, Nicola and Peduto, Anthony J and Bournazos, Adam and Waddell, Leigh B and Farrar, Michelle A and Sampaio, Hugo A and Teoh, Hooi Ling and Lamont, Phillipa J and Mowat, David and Fitzsimons, Robin B and Corbett, Alastair J and Ryan, Monique M and O{\textquoteright}Grady, Gina L and Sandaradura, Sarah A and Ghaoui, Roula and Joshi, Himanshu and Marshall, Jamie L and Nolan, Melinda A and Kaur, Simranpreet and Punetha, Jaya and Topf, Ana and Harris, Elizabeth and Bakshi, Madhura and Genetti, Casie A and Marttila, Minttu and Werlauff, Ulla and Streichenberger, Nathalie and Pestronk, Alan and Mazanti, Ingrid and Pinner, Jason R and Vuillerot, Carole and Grosmann, Carla and Camacho, Ana and Mohassel, Payam and Leach, Meganne E and Foley, A Reghan and Bharucha-Goebel, Diana and Collins, James and Connolly, Anne M and Gilbreath, Heather R and Iannaccone, Susan T and Castro, Diana and Cummings, Beryl B and Webster, Richard I and Lazaro, Le{\"\i}la and Vissing, John and Coppens, Sandra and Deconinck, Nicolas and Luk, Ho-Ming and Thomas, Neil H and Foulds, Nicola C and Illingworth, Marjorie A and Ellard, Sian and McLean, Catriona A and Phadke, Rahul and Ravenscroft, Gianina and Witting, Nanna and Hackman, Peter and Richard, Isabelle and Cooper, Sandra T and Kamsteeg, Erik-Jan and Hoffman, Eric P and Bushby, Kate and Straub, Volker and Udd, Bjarne and Ferreiro, Ana and North, Kathryn N and Clarke, Nigel F and Lek, Monkol and Beggs, Alan H and B{\"o}nnemann, Carsten G and MacArthur, Daniel G and Granzier, Henk and Davis, Mark R and Laing, Nigel G} }