bims-meglyc 2024-07-07 papers

Issue of 2024‒07‒07
four papers selected by
Silvia Radenkovic, UMC Utrecht

Mol Genet Metab. 2024 Jun 06. pii: S1096-7192(24)00393-7. [Epub ahead of print]142(4): 108509

Frontiers in congenital disorders of glycosylation consortium, a cross-sectional study report at year 5 of 280 individuals in the natural history cohort.

Christina Lam, Fernando Scaglia, Gerard T Berry, Austin Larson, Kyriakie Sarafoglou, Hans C Andersson, Evgenia Sklirou, Queenie K G Tan, Rodrigo T Starosta, Mustafa Sadek, Lynne Wolfe, Seishu Horikoshi, May Ali, Rita Barone, Teresa Campbell, Irene J Chang, Kiaira Coles, Edward Cook, Erik A Eklund, Nicole M Engelhardt, Mary Freeman, Jennifer Friedman, Debbie Y T Fu, Grace Botzo, Brandy Rawls, Christien Hernandez, Christin Johnsen, Kierstin Keller, Sara Kramer, Bryce Kuschel, Angela Leshinski, Ivan Martinez-Duncker, Gina L Mazza, Saadet Mercimek-Andrews, Bradley S Miller, Karthik Muthusamy, Juanita Neira, Marc C Patterson, Natalie Pogorelc, Lex N Powers, Elizabeth Ramey, Michaela Reinhart, Audrey Squire, Jenny Thies, Jerry Vockley, Hayden Vreugdenhil, Peter Witters, Mehdi Youbi, Aziza Zeighami, Roni Zemet, Andrew C Edmondson, Eva Morava.

OBJECTIVE: Our report describes clinical, genetic, and biochemical features of participants with a molecularly confirmed congenital disorder of glycosylation (CDG) enrolled in the Frontiers in Congenital Disorders of Glycosylation (FCDGC) Natural History cohort at year 5 of the study.METHODS: We enrolled individuals with a known or suspected CDG into the FCDGC Natural History Study, a multicenter prospective and retrospective natural history study of all genetic causes of CDG. We conducted a cross-sectional analysis of baseline study visit data from participants with confirmed CDG who were consented into the FCDGC Natural History Study (5U54NS115198) from October 2019 to November 2023.
RESULTS: Three hundred thirty-three subjects consented to the FCDGC Natural History Study. Of these, 280 unique individuals had genetic data available that was consistent with a diagnosis of CDG. These 280 individuals were enrolled into the study between October 8, 2019 and November 29, 2023. One hundred forty-one (50.4%) were female, and 139 (49.6%) were male. Mean and median age at enrollment was 10.1 and 6.5 years, respectively, with a range of 0.22 to 71.4 years. The cohort encompassed individuals with disorders of N-linked protein glycosylation (57%), glycosylphosphatidylinositol anchor disorder (GPI anchor) (15%), disorders of Golgi homeostasis, trafficking and transport (12%), dolichol metabolism disorders (5%), disorders of multiple pathways (6%), and other (5%). The most frequent presenting symptom(s) leading to diagnosis were developmental delay/disability (77%), followed by hypotonia (56%) and feeding difficulties (42%). Mean and median time between first related symptom and diagnosis was 2.7 and 0.8 years, respectively. One hundred percent of individuals in our cohort had developmental differences/disabilities at the time of their baseline visit, followed by 97% with neurologic involvement, 91% with gastrointestinal (GI)/liver involvement, and 88% with musculoskeletal involvement. Severity of disease in individuals was scored on the Nijmegen Progression CDG Rating Scale (NPCRS) with 27% of scores categorized as mild, 44% moderate, and 29% severe. Of the individuals with N-linked protein glycosylation defects, 83% of those with data showed a type 1 pattern on carbohydrate deficient transferrin (CDT) analysis including 82/84 individuals with PMM2-CDG, 6% a type 2 pattern, 1% both type 1 and type 2 pattern and 10% a normal or nonspecific pattern. One hundred percent of individuals with Golgi homeostasis and trafficking defects with data showed a type 2 pattern on CDT analysis, while Golgi transport defect showed a type II pattern 73% of the time, a type 1 pattern for 7%, and 20% had a normal or nonspecific pattern. Most of the variants documented were classified as pathogenic or likely pathogenic using ACMG criteria. For the majority of the variants, the predicted molecular consequence was missense followed by nonsense and splice site, and the majority of the diagnoses are inherited in an autosomal recessive pattern but with disorders of all major nuclear inheritance included.
DISCUSSION: The FCDGC Natural History Study serves as an important resource to build future research studies, improve clinical care, and prepare for clinical trial readiness. Herein is the first overview of CDG participants of the FCDGC Natural History Study.

Keywords: CDG; Congenital disorders of glycosylation; NPCRS; Natural history

DOI: https://doi.org/10.1016/j.ymgme.2024.108509

Mol Genet Metab. 2024 Jul 02. pii: S1096-7192(24)00414-1. [Epub ahead of print]142(4): 108530

Coagulation abnormalities and vascular complications are common in PGM1-CDG.

Silvia Radenkovic, Sofie Bleukx, Nicole Engelhardt, Erik Eklund, Saadet Mercimek-Andrews, Andrew C Edmondson, Eva Morava.

Phosphoglucomutase-1-congenital disorder of glycosylation (PGM1-CDG) is a rare genetic disorder caused by biallelic variants in the PGM1 gene, leading to the deficiency of the PGM1 enzyme. The most common clinical presentations include muscle involvement, failure to thrive, cleft palate, and cardiac involvement. Abnormal serum N-glycosylation, hypoglycemia, and liver function abnormalities including coagulation abnormalities are the most common laboratory abnormalities. While PGM1-CDG has been extensively studied, little is known about the extent of the coagulation abnormalities in individuals with PGM1-CDG. Unlike most CDG, some symptoms of PGM1-CDG are treatable with D-galactose (D-gal) supplementation, though reliable clinical endpoints are necessary to appropriately evaluate the potential improvement with D-gal in PGM1-CDG. Here, we aimed to describe the incidence of coagulation abnormalities in PGM1-CDG and their evolution, their relation to clinical events, and the ability of D-gal treatment to improve them. A retrospective analysis was conducted on 73 reported individuals. All individuals had a molecularly confirmed PGM1-CDG diagnosis. All incidences of antithrombin (AT), aPTT, PT, factor (F) XI, FX, FIX, FVII, protein C and protein S data and major clinical events related to coagulation abnormalities, were collected. Coagulation information was available for only 58.9 % of the reported individuals, out of which 67.4 % of PGM1-CDG individuals were reported to have abnormalities. The most frequently observed abnormality was AT (mean: 30.8% R:80-120 %) deficiency. Four individuals had major thrombotic events. Coagulation status on D-gal treatment, were reported in 19 individuals. Several factors showed improvement including AT (mean: 64.5 %), indicating galactose is beneficial in treating coagulation abnormalities in PGM1-CDG. Due to the scarcity of the reported data on coagulation parameters, we also evaluated data collected in sixteen PGM1-CDG individuals enrolled in the FCDGC Natural History Study. Longitudinal data showed improvements in several coagulant parameters and disease severity improved for almost all patients of whom we had multiple datapoints on D-gal. AT showed significant improvement on D-gal. We conclude that coagulation abnormalities are frequently present in PGM1-CDG and show improvement on D-gal. We recommend coagulation parameters should be routinely checked in individuals with PGM1-CDG or suspected of having PGM1-CDG. Finally, AT may be used as a primary or secondary clinical endpoint for upcoming clinical trials in PGM1-CDG individuals.

Keywords: Coagulation abnormalities; Congenital disorder(s) of glycosylation; Galactose therapy; Phosphoglucomutase-1

DOI: https://doi.org/10.1016/j.ymgme.2024.108530

Front Genet. 2024 ;15 1430414

Editorial: Inborn errors of carbohydrate metabolism.

Iván Martínez-Duncker, Ida Vanessa Doederlein-Schwartz, Melania Abreu-González, José Elías García-Ortiz.

Keywords: CDG (congenital disorder of glycosylation); ERT (enzyme replacement therapy); Pompe (glycogen storage disease type 2 / II); adult polyglucosan body disease (APBD); diabetes mellitus; lysosomal storage disease; metabolism; rare disease (RD)

DOI: https://doi.org/10.3389/fgene.2024.1430414

FASEB J. 2024 Jul 15. 38(13): e23797

Impaired myoblast differentiation and muscle IGF-1 receptor signaling pathway activation after N-glycosylation inhibition.

Giosuè Annibalini, Laura Di Patria, Giacomo Valli, Matteo Bocconcelli, Roberta Saltarelli, Lorenzo Ferri, Laura Barberi, Fabiana Fanelli, Amelia Morrone, Rita Barone, Renzo Guerrini, Antonio Musarò, Vilberto Stocchi, Elena Barbieri.

The role of N-glycosylation in the myogenic process remains poorly understood. Here, we evaluated the impact of N-glycosylation inhibition by Tunicamycin (TUN) or by phosphomannomutase 2 (PMM2) gene knockdown, which encodes an enzyme essential for catalyzing an early step of the N-glycosylation pathway, on C2C12 myoblast differentiation. The effect of chronic treatment with TUN on tibialis anterior (TA) and extensor digitorum longus (EDL) muscles of WT and MLC/mIgf-1 transgenic mice, which overexpress muscle Igf-1Ea mRNA isoform, was also investigated. TUN-treated and PMM2 knockdown C2C12 cells showed reduced ConA, PHA-L, and AAL lectin binding and increased ER-stress-related gene expression (Chop and Hspa5 mRNAs and s/uXbp1 ratio) compared to controls. Myogenic markers (MyoD, myogenin, and Mrf4 mRNAs and MF20 protein) and myotube formation were reduced in both TUN-treated and PMM2 knockdown C2C12 cells. Body and TA weight of WT and MLC/mIgf-1 mice were not modified by TUN treatment, while lectin binding slightly decreased in the TA muscle of WT (ConA and AAL) and MLC/mIgf-1 (ConA) mice. The ER-stress-related gene expression did not change in the TA muscle of WT and MLC/mIgf-1 mice after TUN treatment. TUN treatment decreased myogenin mRNA and increased atrogen-1 mRNA, particularly in the TA muscle of WT mice. Finally, the IGF-1 production and IGF1R signaling pathways activation were reduced due to N-glycosylation inhibition in TA and EDL muscles. Decreased IGF1R expression was found in TUN-treated C2C12 myoblasts which was associated with lower IGF-1-induced IGF1R, AKT, and ERK1/2 phosphorylation compared to CTR cells. Chronic TUN-challenge models can help to elucidate the molecular mechanisms through which diseases associated with aberrant N-glycosylation, such as Congenital Disorders of Glycosylation (CDG), affect muscle and other tissue functions.

Keywords: PMM2 ; IGF1R signaling pathway; congenital disorders of glycosylation; glycosylation; muscle atrophy; myoblast differentiation

DOI: https://doi.org/10.1096/fj.202400213RR