| Finding type | Metric/value | Population | Source (paper + year + DOI) | Notes |
|---|---:|---|---|---|
| Electrophysiologic definition | CMT1: NCV in arms **<38 m/s** | General CMT classification | Okamoto & Takashima 2023, *Genes*, DOI: 10.3390/genes14071391 (pqac-00000013) | Review states a consistent slow NCV <38 m/s represents demyelinating CMT1. |
| Electrophysiologic definition | CMT2: NCV **>38 m/s** | General CMT classification | Okamoto & Takashima 2023, *Genes*, DOI: 10.3390/genes14071391 (pqac-00000013) | Review states NCV >38 m/s is distinctive of axonal CMT2. |
| Electrophysiologic definition | Transitional/intermediate NCV **25–45 m/s** | General CMT classification; often CMTX1/transition forms | Okamoto & Takashima 2023, *Genes*, DOI: 10.3390/genes14071391 (pqac-00000013) | Useful differential context when values are not clearly demyelinating or axonal. |
| Electrophysiologic definition | CMT1: upper-limb MNCV **<25 m/s** | UCL inherited neuropathy centre phenotype definition | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011) | Centre-specific research definition for demyelinating CMT1. |
| Electrophysiologic definition | CMT2: axonal neuropathy (threshold not fully visible in excerpt) | UCL inherited neuropathy centre phenotype definition | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011) | Excerpt explicitly labels CMT2 as axonal neuropathy; exact numeric cutoff is truncated in the provided text. |
| Diagnostic yield | **76.9% (1165/1515)** overall genetic diagnosis rate | Entire CMT and related disorders cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011) | Excluding hereditary ATTR amyloidosis. |
| Diagnostic yield | **48.6% (143/294)** solved | CMT2 subgroup | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000012) | Confirms that axonal CMT remains unsolved in about half of cases. |
| Diagnostic yield | **31.8% (74/233)** achieved a diagnosis in 100KGP | Cases recruited to UK 100,000 Genomes Project | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011) | Includes cases later diagnosed outside the original 100KGP report. |
| Diagnostic yield | **19.7% (46/233)** true WGS diagnostic rate | Cases recruited to UK 100,000 Genomes Project | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011) | “True” rate after excluding 28 otherwise-diagnosed cases. |
| Diagnostic yield | **3.5%** overall diagnostic uplift from WGS | Entire cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011) | Incremental improvement attributed to WGS. |
| Common gene (adult/mixed cohort) | **PMP22 duplication 43.3% (505/1165 solved); 33.3% (505/1515 total)** | Entire Record cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011, pqac-00000012) | Most common overall diagnosis. |
| Common gene (adult/mixed cohort) | **GJB1 13.0% (151/1165 solved); 10.0% (151/1515 total)** | Entire Record cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011, pqac-00000012) | Second most common overall diagnosis. |
| Common gene (adult/mixed cohort) | **PMP22 deletion 6.2% (72/1165 solved); 4.8% (72/1515 total)** | Entire Record cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011, pqac-00000012) | HNPP-associated. |
| Common gene (adult/mixed cohort) | **MFN2 3.9% (46/1165 solved); 3.0% (46/1515 total)** | Entire Record cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000011, pqac-00000012) | Most common single genetic diagnosis in CMT2 overall. |
| Common gene (adult/mixed cohort) | **MFN2 30.1% (43/143 solved CMT2)** | Solved CMT2 cases in Record cohort | Record et al. 2024, *Brain*, DOI: 10.1093/brain/awae064 (pqac-00000012) | Dominant contributor within solved axonal CMT2. |
| Common gene (pediatric cohort) | **PMP22 duplication 18.2% (33/181)** | Chinese pediatric CMT cohort | Ma et al. 2023, *Frontiers in Genetics*, DOI: 10.3389/fgene.2023.1188361 (pqac-00000014, pqac-00000015) | Most frequent genetic diagnosis overall in this pediatric series. |
| Common gene (pediatric cohort) | **MFN2 7.7% (14/181)** | Chinese pediatric CMT cohort | Ma et al. 2023, *Frontiers in Genetics*, DOI: 10.3389/fgene.2023.1188361 (pqac-00000014, pqac-00000015) | Most frequent cause of axonal CMT in this cohort. |
| Common gene (pediatric cohort) | **GJB1 6.6% (12/181)** | Chinese pediatric CMT cohort | Ma et al. 2023, *Frontiers in Genetics*, DOI: 10.3389/fgene.2023.1188361 (pqac-00000014, pqac-00000015) | Most common cause of CMTX in this cohort. |
| Common gene (pediatric cohort) | **GDAP1 5.0% (9/181)** | Chinese pediatric CMT cohort | Ma et al. 2023, *Frontiers in Genetics*, DOI: 10.3389/fgene.2023.1188361 (pqac-00000015) | Among next most frequent genes in pediatric series. |
| Common gene (pediatric cohort) | **PMP22 point mutations 4.4% (8/181)** | Chinese pediatric CMT cohort | Ma et al. 2023, *Frontiers in Genetics*, DOI: 10.3389/fgene.2023.1188361 (pqac-00000015) | Reported as severe genotypes, often de novo. |
| Common gene (pediatric cohort) | **IGHMBP2 3.3% (6/181); MORC2 3.3% (6/181)** | Chinese pediatric CMT cohort | Ma et al. 2023, *Frontiers in Genetics*, DOI: 10.3389/fgene.2023.1188361 (pqac-00000015) | Both among the top recurrent pediatric diagnoses. |


*Table: This table summarizes key electrophysiologic cutoffs, diagnostic-yield metrics, and recurrent gene frequencies for Charcot-Marie-Tooth disease type 2 and related CMT cohorts. It is useful for quickly comparing how CMT2 is defined clinically and how often major genes and testing strategies contribute to diagnosis.*