OBJECTIVE: To test the hypothesis that monogenic neuropathies such as Charcot-Marie-Tooth disease (CMT) contribute to frequent but often unexplained neuropathies in the elderly, we performed genetic analysis of 230 patients with unexplained axonal neuropathies and disease onset ≥35 years. METHODS: We recruited patients, collected clinical data, and conducted whole-exome sequencing (WES; n = 126) and MME single-gene sequencing (n = 104). We further queried WES repositories for MME variants and measured blood levels of the MME-encoded protein neprilysin. RESULTS: In the WES cohort, the overall detection rate for assumed disease-causing variants in genes for CMT or other conditions associated with neuropathies was 18.3% (familial cases 26.4%, apparently sporadic cases 12.3%). MME was most frequently involved and accounted for 34.8% of genetically solved cases. The relevance of MME for late-onset neuropathies was further supported by detection of a comparable proportion of cases in an independent patient sample, preponderance of MME variants among patients compared to population frequencies, retrieval of additional late-onset neuropathy patients with MME variants from WES repositories, and low neprilysin levels in patients' blood samples. Transmission of MME variants was often consistent with an incompletely penetrant autosomal-dominant trait and less frequently with autosomal-recessive inheritance. CONCLUSIONS: A detectable fraction of unexplained late-onset axonal neuropathies is genetically determined, by variants in either CMT genes or genes involved in other conditions that affect the peripheral nerves and can mimic a CMT phenotype. MME variants can act as completely penetrant recessive alleles but also confer dominantly inherited susceptibility to axonal neuropathies in an aging population.

• MeSH
• Charcotova-Marieova-Toothova nemoc krev   genetika   MeSH
• genetická predispozice k nemoci genetika   MeSH
• hereditární motorické a senzitivní neuropatie krev   genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• neprilysin krev   genetika   MeSH
• sekvenování exomu MeSH
• senioři MeSH
• stárnutí * krev   MeSH
• věk při počátku nemoci MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

BACKGROUND: Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited neuropathy, a debilitating disease without known cure. Among patients with CMT1A, disease manifestation, progression and severity are strikingly variable, which poses major challenges for the development of new therapies. Hence, there is a strong need for sensitive outcome measures such as disease and progression biomarkers, which would add powerful tools to monitor therapeutic effects in CMT1A. METHODS: We established a pan-European and American consortium comprising nine clinical centres including 311 patients with CMT1A in total. From all patients, the CMT neuropathy score and secondary outcome measures were obtained and a skin biopsy collected. In order to assess and validate disease severity and progression biomarkers, we performed qPCR on a set of 16 animal model-derived potential biomarkers in skin biopsy mRNA extracts. RESULTS: In 266 patients with CMT1A, a cluster of eight cutaneous transcripts differentiates disease severity with a sensitivity and specificity of 90% and 76.1%, respectively. In an additional cohort of 45 patients with CMT1A, from whom a second skin biopsy was taken after 2-3 years, the cutaneous mRNA expression of GSTT2, CTSA, PPARG, CDA, ENPP1 and NRG1-Iis changing over time and correlates with disease progression. CONCLUSIONS: In summary, we provide evidence that cutaneous transcripts in patients with CMT1A serve as disease severity and progression biomarkers and, if implemented into clinical trials, they could markedly accelerate the development of a therapy for CMT1A.

• MeSH
• biopsie MeSH
• Charcotova-Marieova-Toothova nemoc krev   genetika   terapie   MeSH
• dospělí MeSH
• fosfodiesterasy genetika   MeSH
• genetická transkripce genetika   MeSH
• genetické markery genetika   MeSH
• glutathiontransferasa genetika   MeSH
• glykoproteiny genetika   MeSH
• kathepsin A genetika   MeSH
• kůže patologie   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé středního věku MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• neuregulin-1 genetika   MeSH
• PPAR gama genetika   MeSH
• prognóza MeSH
• progrese nemoci * MeSH
• pyrofosfatasy genetika   MeSH
• senioři MeSH
• výsledek terapie * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH