@article {974, title = {Variants in GNAI1 cause a syndrome associated with variable features including developmental delay, seizures, and hypotonia.}, journal = {Genet Med}, volume = {23}, year = {2021}, month = {2021 05}, pages = {881-887}, abstract = {

PURPOSE: Neurodevelopmental disorders (NDDs) encompass a spectrum of genetically heterogeneous disorders with features that commonly include developmental delay, intellectual disability, and autism spectrum disorders. We sought to delineate the molecular and phenotypic spectrum of a novel neurodevelopmental disorder caused by variants in the GNAI1 gene.

METHODS: Through large cohort trio-based exome sequencing and international data-sharing, we identified 24 unrelated individuals with NDD phenotypes and a variant in GNAI1, which encodes the inhibitory Gαi1 subunit of heterotrimeric G-proteins. We collected detailed genotype and phenotype information for each affected individual.

RESULTS: We identified 16 unique variants in GNAI1 in 24 affected individuals; 23 occurred de novo and 1 was inherited from a mosaic parent. Most affected individuals have a severe neurodevelopmental disorder. Core features include global developmental delay, intellectual disability, hypotonia, and epilepsy.

CONCLUSION: This collaboration establishes GNAI1 variants as a cause of NDDs. GNAI1-related NDD is most often characterized by severe to profound delays, hypotonia, epilepsy that ranges from self-limiting to intractable, behavior problems, and variable mild dysmorphic features.

}, keywords = {Child, Developmental Disabilities, Humans, Intellectual Disability, Muscle Hypotonia, Neurodevelopmental Disorders, Seizures, Whole Exome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-020-01076-8}, author = {Muir, Alison M and Gardner, Jennifer F and van Jaarsveld, Richard H and de Lange, Iris M and van der Smagt, Jasper J and Wilson, Golder N and Dubbs, Holly and Goldberg, Ethan M and Zitano, Lia and Bupp, Caleb and Martinez, Jose and Srour, Myriam and Accogli, Andrea and Alhakeem, Afnan and Meltzer, Meira and Gropman, Andrea and Brewer, Carole and Caswell, Richard C and Montgomery, Tara and McKenna, Caoimhe and McKee, Shane and Powell, Corinna and Vasudevan, Pradeep C and Brady, Angela F and Joss, Shelagh and Tysoe, Carolyn and Noh, Grace and Tarnopolsky, Mark and Brady, Lauren and Zafar, Muhammad and Schrier Vergano, Samantha A and Murray, Brianna and Sawyer, Lindsey and Hainline, Bryan E and Sapp, Katherine and DeMarzo, Danielle and Huismann, Darcy J and Wentzensen, Ingrid M and Schnur, Rhonda E and Monaghan, Kristin G and Juusola, Jane and Rhodes, Lindsay and Dobyns, William B and Lecoquierre, Francois and Goldenberg, Alice and Polster, Tilman and Axer-Schaefer, Susanne and Platzer, Konrad and Kl{\"o}ckner, Chiara and Hoffman, Trevor L and MacArthur, Daniel G and O{\textquoteright}Leary, Melanie C and VanNoy, Grace E and England, Eleina and Varghese, Vinod C and Mefford, Heather C} } @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} }