High diagnostic yield with algorithmic molecular approach on hereditary neuropathies

SUMMARY OBJECTIVE: Charcot-Marie-Tooth disease covers a group of inherited peripheral neuropathies. The aim of this study was to investigate the effect of targeted next-generation sequencing panels on the molecular diagnosis of Charcot-Marie-Tooth disease and its subtypes in routine clinical practice, and also to show the limitations and importance of next-generation sequencing in the diagnosis of Charcot-Marie-Tooth diseases. METHODS: This is a retrospective study. Three different molecular methods (multiplex ligation probe amplification, next-generation sequencing, and whole-exome sequencing) were used to detect the mutations related to Charcot-Marie-Tooth disease. RESULTS: In total, 64 patients (33 males and 31 females) with suspected Charcot-Marie-Tooth disease were analyzed for molecular etiology. In all, 25 (39%) patients were diagnosed by multiplex ligation probe amplification. With an extra 11 patients with normal PMP22 multiplex ligation probe amplification results that were consulted to our laboratory for further genetic analysis, a total of 50 patients underwent next-generation sequencing for targeted gene panels associated with Charcot-Marie-Tooth disease. Notably, 18 (36%) patients had pathogenic/likely pathogenic variants. Whole-exome sequencing was performed on five patients with normal next-generation sequencing results; the diagnostic yield by whole-exome sequencing was 80% and it was higher in the childhood group. CONCLUSION: The molecular etiology in Charcot-Marie-Tooth disease patients can be determined according to pre-test evaluation, deciding the inheritance type with pedigree analysis, the clinical phenotype, and an algorithm for the genetic analysis. The presence of patients without a molecular diagnosis in all the literature suggests that there are new genes or mechanisms waiting to be discovered in the etiology of Charcot-Marie-Tooth disease.

Evaluation of TLR2 and TLR4 Polymorphisms in Chronic HBV Infection.

Aims: Toll-like receptors (TLRs) play a central role in initiating innate response by mediating inflammatory reactions against a wide range of pathogens. We aimed to determine if TLR2 Arg753Gln, TLR4 Asp299Gly and Thr399Ile polymorphisms are associated with chronic hepatitis B (HBV) infection. Study Design: A case-control study. Methodology: Genomic DNA was obtained from peripheral blood of 100 patients with chronic HBV infection and 108 healthy volunteer controls. The TLR2 and TLR4 polymorphisms were genotyped by the polymerase chain reaction-restriction length polymorphism (PCR-RFLP) technique. Results: The distribution of the TLR2 Arg753Gln, TLR4 Asp299Gly and TLR4 Thr399Ile variants were not significantly different between patients and controls (P = .05). Conclusion: Our results showed that there is no association between TLR2 Arg753Gln, TLR4 Asp299Gly and TLR4 Thr399Ile polymorphisms and chronic HBV infection.