| Domain | Best-supported finding | Evidence type/sample | Key quantitative detail | Confidence/limitation |
|---|---|---|---|---|
| Disease identity | CMTDIG is the dominant-intermediate NEFL-associated CMT entity and overlaps clinically/genetically with NEFL-related CMT1F and CMT2E classifications rather than forming a sharply isolated syndrome | Disease-target aggregation plus review/cohort synthesis | MONDO:0036484 linked to NEFL; review notes NEFL variants cause demyelinating, axonal, and intermediate CMT forms; NF-related CMT accounts for ~1% of diagnosed CMT cases (pqac-00000000, pqac-00000016) | Moderate confidence; nomenclature is stable but human reports often classify the same NEFL families as CMT1F, CMT2E, or intermediate depending on conduction/pathology |
| Foundational human family | Heterozygous NEFL p.Glu397Lys was reported in a multigenerational family with autosomal dominant, clinically heterogeneous neuropathy in the intermediate/demyelinating range | Human clinical family study; 3 generations, 6 mutation carriers/affected relatives described (pqac-00000001, pqac-00000003) | Variant absent in 65 controls; by 2004, 11 NEFL mutations affecting 8 amino acids had been reported, ~2% of 323 CMT cases screened (pqac-00000001, pqac-00000006) | High confidence for this family; low generalizability because subtype-specific literature is sparse and older |
| 2024 variant landscape | Modern literature synthesis reports a broader NEFL disease spectrum with mostly heterozygous missense variants acting through gain-of-function mechanisms; somatic mosaicism can also be pathogenic | 2024 retrospective case study + literature review | 34 distinct CMT-causing NEFL variants in 174 reported patients; first reported pathogenic somatic NEFL mosaicism at 15% for p.Pro8Ser father (pqac-00000016, pqac-00000017) | High confidence for counts at publication date; counts will change as new cases accumulate |
| Core phenotypes / natural history | NEFL-related CMT commonly causes distal-predominant sensorimotor neuropathy with foot deformity and variable onset/severity; severe alleles can produce early-onset multisystem neuromuscular phenotypes | Human family studies | p.Glu397Lys family: onset ranged from age 4 to 82 years, with two clinically/electrophysiologically healthy carriers at age 21; severe family with NEFL nonsense variant had 4 affected members, infantile hypotonia, contractures, scoliosis, wheelchair dependence, and one death at 35 years likely from respiratory insufficiency (pqac-00000003, pqac-00000009, pqac-00000011) | High confidence for variable expressivity and age-dependent/incomplete penetrance; phenotype frequencies across CMTDIG specifically are unavailable |
| Electrophysiology and pathology | Dominant-intermediate labeling is supported by slowed motor conduction plus mixed axonal-demyelinating nerve pathology | Human electrophysiology and sural nerve biopsy | Motor NCVs in reported NEFL family ranged 27–43 m/s; peroneal NCV 25–27 m/s in some subjects; myelin area 12–16% versus ~23% normal; onion bulbs, loss of large myelinated fibers, atrophic axons, regenerated clusters (pqac-00000001, pqac-00000003, pqac-00000012, pqac-00000013) | High confidence in family-level evidence; pathology is based on very small numbers and may not represent all NEFL variants |
| Mechanism / pathophysiology | Pathogenic NEFL variants disrupt neurofilament assembly/organization, axonal caliber, intracellular transport, and likely axon-Schwann-cell interactions; some effects are modulated by post-translational regulation such as O-GlcNAcylation | Cell biology, review synthesis, and inference from human pathology | Neurofilament assembly defect and organelle transport disruption highlighted in 2024 review; 2023 O-GlcNAc study identified 5 NF-L O-GlcNAc sites and showed mutant NF-L can resist O-GlcNAc effects on assembly; severe NCV slowing may reflect axon/axonal-caliber loss and secondary demyelination (pqac-00000016, pqac-00000018) | Moderate confidence; aggregation/assembly defects are demonstrated in models, while the precise causal link to each human phenotype remains partly inferred |
| Model organisms and human cellular models | N98S is the best-developed experimental NEFL model, reproducing inclusion pathology and axonal structural abnormalities; patient iPSC-derived motor neurons recapitulate disease-relevant biomarkers | Knock-in mouse and patient-derived iPSC motor neuron models | NeflN98S/+ mice showed tremor, hindlimb clasping, inclusions in spinal neurons, abnormalities by postnatal day 7, fewer neurofilaments, more microtubules, and reduced axonal diameters; P8R mice were behaviorally similar to wild type (pqac-00000008, pqac-00000016) | High confidence for N98S model validity; model findings may not extrapolate to all NEFL variants or specifically to p.Glu397Lys/CMTDIG |
| Experimental therapy | Allele-preferential ASO therapy is the most advanced NEFL-targeted approach currently gathered, with biomarker rescue in a preclinical human model | 2024 preclinical therapeutic study in patient iPSC-derived motor neurons | ASO produced ~20% reduction of mutant p.N98S allele expression and ~38% reduction of total NEFL transcript, with decreased supernatant NF-L and peripherin biomarkers (pqac-00000002) | Moderate confidence; strong proof-of-concept but not yet human clinical efficacy or safety data for NEFL/CMTDIG |
| Diagnostics | Diagnosis currently depends on clinical neuropathy assessment plus molecular testing, with WGS improving but not replacing phenotype-driven workflows | Specialist-center cohort and hereditary neuropathy testing studies | In a 1515-patient inherited neuropathy center cohort, intermediate CMT accounted for 205/1515 (13.5%) and had 81.0% genetic diagnosis; overall diagnostic rate 76.9%, WGS diagnostic uplift 3.5%, true 100KGP WGS rate 19.7% (46/233) (pqac-00000016) | Moderate confidence for general CMT diagnostics; no CMTDIG-specific diagnostic algorithm validated beyond identifying heterozygous NEFL variants via panels/WES/WGS |
| Treatment gap / current care | No disease-modifying therapy specific to NEFL-related CMTDIG was identified; present real-world management is supportive, while NEFL-targeted precision therapy remains preclinical | Evidence gap plus broader CMT practice context | Clinical trial searches retrieved broader CMT studies but no NEFL/CMTDIG-specific interventional trial; customized ASO remains preclinical proof-of-concept (pqac-00000002) | High confidence for current treatment gap; limitation is absence of subtype-specific management trials and sparse published QoL/outcome data |


*Table: This table summarizes the strongest currently gathered evidence for NEFL-related dominant-intermediate Charcot-Marie-Tooth disease and overlapping NEFL neuropathies. It is calibrated to separate well-supported family/model findings from areas where evidence remains sparse or indirect.*