Isolated Peripheral Neuropathy in Atypical Metachromatic Leukodystrophy: A Recurrent Mutation
Bibliographic record
Abstract
BACKGROUND: Metachromatic leukodystrophy (MLD) is a genetic neurodegenerative disorder resulting from a deficiency of arylsulfatase A. Late onset forms are relatively rare. Central nervous system (CNS) involvement is characteristic at all ages. METHODS: A patient in her late 40s with peripheral neuropathy was assessed by EEG, evoked potentials, CT and nerve conduction studies. Nerve and muscle biopsy samples were investigated by electron microscopy. Arylsulfatase A activity in leukocytes and excreted cerebroside sulfate were determined. The arylsulfatase A gene was investigated for mutations using polymerase chain reaction (PCR) and DNA sequencing. The identified mutation was expressed transiently in African green monkey kidney (COS) cells to determine the effect of the mutation on arylsulfatase A activity. RESULTS: Central nervous system functions were normal. Nerve conduction velocities were decreased. Sural nerve biopsy showed inclusions typical of MLD. Arylsulfatase A was less than 5% of normal. A homozygous mutation thr286pro was identified in the arylsulfatase A gene and demonstrated to be deleterious through transient expression studies. CONCLUSIONS: Our patient has a progressive peripheral neuropathy but has apparently intact CNS function at her present age of 57 years. Biochemical, physiological and pathological findings are consistent with a diagnosis of MLD. A homozygous mutation, thr286pro, found in her arylsulfatase A gene, decreased enzyme activity to a level consistent with a late onset form of MLD.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".