Mutational analysis of Greek patients with suspected hereditary neuropathy with liability to pressure palsies (HNPP): a 15-year experience

Mutational screening of Greek patients with axonal Charcot-Marie-Tooth disease using targeted next-generation sequencing: Clinical and molecular spectrum delineation

BACKGROUND AND AIMS

Axonal forms of Charcot-Marie-Tooth disease (CMT) are classified as CMT2, distal hereditary motor neuropathy (dHMN) or hereditary sensory neuropathy (HSN) and can be caused by mutations in over 100 genes. We presently aimed to investigate for the first time the genetic landscape of axonal CMT in the Greek population.

METHODS

Sixty index patients with CMT2, dHMN or HSN were screened by a combination of Sanger sequencing (GJB1) and next-generation sequencing custom-made gene panel covering 24 commonly mutated genes in axonal CMT.

RESULTS

Overall, 20 variants classified as pathogenic or likely pathogenic were identified in heterozygous state in 20 index cases, representing 33.3% of the cohort. Of these, 14 were known pathogenic/likely pathogenic and six were designated as such according to ACMG classification, after in silico evaluation, testing for familial segregation and further literature review. The most frequently involved genes were GJB1 (11.7%), MPZ (5%) and MFN2 (5%), followed by DNM2 (3.3%) and LRSAM1 (3.3%). Single cases were identified with mutations in BSCL2, HSPB1 and GDAP1.

INTERPRETATION

A wide phenotypic variability in terms of severity and age of onset was noted. Given the limited number of genes tested, the diagnostic yield of the present panel compares favourably with studies in other European populations. Our study delineates the genetic and phenotypic variability of inherited axonal neuropathies in the Greek population and contributes to the pathogenicity characterization of further variants linked to axonal neuropathies.

Hereditary neuropathy with liability to pressure palsies misdiagnosed as Guillain-Barré Syndrome: A case report

RATIONALE

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominantly inherited genetic disease characterized by recurrent numbness and limb weakness. HNPP can be easily missed or misdiagnosed because of electrophysiological heterogeneity and atypical clinical symptoms. To date, diagnosis of HNPP remains a challenge for clinicians.

PATIENT CONCERNS

Here, we report the case of a 12-year-old woman diagnosed with HNPP, which was initially diagnosed with Guillain-Barré Syndrome (GBS) and treated with intravenous immunoglobulin (IVIG).

DIAGNOSES

Repeat electrodiagnostic studies and genetic testing confirmed the diagnosis of HNPP.

INTERVENTIONS

The patient was treated with neurotrophic drugs and health education, including avoiding maintenance of a certain posture for extended periods, which could damage the peripheral nerves.

OUTCOMES

The patient was discharged 5 days later. The patient was free from recurrence after 6 months of follow-up.

LESSONS

This case highlights the complexity of HNPP diagnosis and emphasizes the importance of early identification.