1. Novel variants and clinical symptoms in four new ALG3-CDG patients, review of the literature, and identification of AAGRP-ALG3 as a novel ALG3 variant with alanine and glycine-rich N-terminus.
- Author
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Himmelreich N, Dimitrov B, Geiger V, Zielonka M, Hutter AM, Beedgen L, Hüllen A, Breuer M, Peters V, Thiemann KC, Hoffmann GF, Sinning I, Dupré T, Vuillaumier-Barrot S, Barrey C, Denecke J, Kölfen W, Düker G, Ganschow R, Lentze MJ, Moore S, Seta N, Ziegler A, and Thiel C
- Subjects
- Animals, COS Cells, Cells, Cultured, Child, Preschool, Chlorocebus aethiops, Female, Humans, Infant, Male, Open Reading Frames, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase genetics, Polymorphism, Single Nucleotide, Congenital Disorders of Glycosylation genetics, Mannosyltransferases genetics, Mutation, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase deficiency
- Abstract
ALG3-CDG is one of the very rare types of congenital disorder of glycosylation (CDG) caused by variants in the ER-mannosyltransferase ALG3. Here, we summarize the clinical, biochemical, and genetic data of four new ALG3-CDG patients, who were identified by a type I pattern of serum transferrin and the accumulation of Man
5 GlcNAc2 -PP-dolichol in LLO analysis. Additional clinical symptoms observed in our patients comprise sensorineural hearing loss, right-descending aorta, obstructive cardiomyopathy, macroglossia, and muscular hypertonia. We add four new biochemically confirmed variants to the list of ALG3-CDG inducing variants: c.350G>C (p.R117P), c.1263G>A (p.W421*), c.1037A>G (p.N346S), and the intron variant c.296+4A>G. Furthermore, in Patient 1 an additional open-reading frame of 141 bp (AAGRP) in the coding region of ALG3 was identified. Additionally, we show that control cells synthesize, to a minor degree, a hybrid protein composed of the polypeptide AAGRP and ALG3 (AAGRP-ALG3), while in Patient 1 expression of this hybrid protein is significantly increased due to the homozygous variant c.160_196del (g.165C>T). By reviewing the literature and combining our findings with previously published data, we further expand the knowledge of this rare glycosylation defect., (© 2019 Wiley Periodicals, Inc.)- Published
- 2019
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