P.044 GMPPB mutation causes a muscular dystrophy-myasthenic spectrum
Bibliographic record
Abstract
Background: Mutations in GDP-Mannose Pyrophosphorylase B (GMPPB) cause a spectrum of disease ranging from muscular dystrophy to congenital myasthenic syndrome (CMS). Recognition of neuromuscular junction dysfunction has important treatment implications. Methods: We describe a person with GMPPB mutation causing an overlapping limb girdle muscular dystrophy - myasthenic syndrome with robust response to acetylcholinesterase inhibitors. We review the literature on the muscular dystrophy - CMS and explore the phenotypic features that aid in recognizing neuromuscular junction dysfunction. Results: A 35-year-old woman presented with a 10-year history of debilitating myalgias, symmetrical limb girdle and neck weakness, and chronic CK elevation. Electromyography showed a non-irritable myopathy. Biopsies were consistent with muscular dystrophy. Whole genome sequencing revealed two heterozygous pathogenic mutations in the GMPPB gene, giving a diagnosis of genetically confirmed limb girdle muscular dystrophy. Subsequently, repetitive nerve stimulation revealed decrement in the trapezius muscle suggestive of an overlap myasthenic syndrome. She was started on pyridostigmine resulting in recovery of full motor power with significant functional improvement. Conclusions: Identification and treatment of neuromuscular junction dysfunction caused by GMPPB mutations can significantly improve motor power and function. Early onset of progressive fatigable proximal weakness, spared ocular and facial muscles, and pyridostigmine responsiveness are important features of GMPPB-related CMS.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".