Show Notes
Dardas Z et al., The American Journal of Human Genetics - This episode reviews Dardas et al. (2025), which identifies bi-allelic UGGT1 variants in 15 affected individuals as the cause of a distinct congenital disorder of glycosylation (UGGT1-CDG), describes the clinical spectrum, and dissects diverse molecular mechanisms that impair UGGT1 function. Key terms: UGGT1, congenital disorder of glycosylation, neurodevelopmental disorder, glucosyltransferase, ER quality control.
Study Highlights:
Fifteen individuals from ten unrelated families were shown to harbor bi-allelic UGGT1 variants associated with a variable multisystem phenotype dominated by global developmental delay, intellectual disability, seizures, dysmorphic facial features, and frequent microcephaly. Functional studies demonstrated that pathogenic variants impair UGGT1 glucosyltransferase catalytic activity, disrupt mRNA splicing, or abrogate ER retention causing extracellular secretion. Genotype–phenotype correlations indicate that bi-allelic loss-of-function alleles associate with greater severity, including infant death, whereas hypomorphic alleles permit survival with neurodevelopmental disability. Standard transferrin testing was often normal, highlighting the need for genetic testing when clinical suspicion for a CDG is high.
Conclusion:
Bi-allelic UGGT1 variants define UGGT1-CDG, a clinically variable N-linked glycosylation disorder in which distinct molecular mechanisms—loss of catalytic activity, splicing disruption, or loss of ER retention—compromise ER quality control and underlie neurologic and multisystem disease; genetic testing is recommended when CDG is suspected as transferrin assays may be normal.
QC:
This episode was checked against the original article PDF and publication metadata.
Scope: article metadata and core scientific claims from the narration, excluding analogies, intro/outro, and music.
Factual QC score: 10/10.
Metadata QC score: 10/10.
Supported core claims: 5.
Claims flagged for review: 0.
Metadata checks passed: 4.
Metadata issues found: 0.
QC result: Pass.
Music:
Enjoy the music based on this article at the end of the episode.
Article title:
Bi-allelic UGGT1 variants cause a congenital disorder of glycosylation
First author:
Dardas Z
Journal:
The American Journal of Human Genetics
DOI:
10.1016/j.ajhg.2025.03.018
Reference:
Dardas Z., Harrold L., Calame D.G., et al. Bi-allelic UGGT1 variants cause a congenital disorder of glycosylation. The American Journal of Human Genetics. 2025;112:1139–1157. https://doi.org/10.1016/j.ajhg.2025.03.018
License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/
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