Genotype-Phenotype Correlations in PMM2-CDG

Area of Science:

• Biochemistry
• Genetics
• Rare Diseases

Background:

• PMM2-CDG is a rare genetic disorder characterized by hypoglycosylation of proteins.
• No clear genotype-phenotype correlations have been established for PMM2-CDG.
• Understanding these correlations is crucial for predicting disease progression and patient outcomes.

Purpose of the Study:

• To investigate genotype-phenotype correlations in PMM2-CDG patients.
• To determine the impact of specific PMM2 variants on disease severity.
• To establish a molecular basis for phenotypic prognosis in PMM2-CDG.

Main Methods:

• Retrospective cohort study of 26 PMM2-CDG patients.
• Analysis of patient genotypes and phenotypes.
• Disease severity assessed using the Nijmegen Pediatric CDG Rating Score (NPCRS).
• Statistical analysis using non-parametric and Chi-Square tests.

Main Results:

• Seventeen different pathogenic variants were analyzed.
• Variants in the stabilization/folding domain, like p.Cys241Ser, correlated with significantly lower NPCRS scores and milder phenotypes.
• Variants in the dimerization domain, such as p.Pro113Leu and p.Phe119Leu, were associated with significantly higher NPCRS scores and more severe clinical courses.
• Variants with zero enzyme activity did not significantly impact the NPCRS.

Conclusions:

• Specific PMM2 variants significantly influence PMM2-CDG phenotype and severity.
• Genotype-based analysis provides valuable insights into disease prognosis.
• This study establishes a foundation for predicting PMM2-CDG clinical outcomes based on molecular findings.