Clinical, electrophysiological, genetic, and imaging features of six Chinese Han patients with hereditary neuropathy with liability to pressure palsies (HNPP)

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.

Two Novel Myelin Protein Zero Mutations in a Group of Chinese Patients

Mutations in the myelin protein zero gene are responsible for the autosomal dominant Charcot-Marie-Tooth disease (CMT). We summarized the genetic and clinical features of six unrelated Chinese families and the genetic spectrum of Chinese patients with myelin protein zero (MPZ) mutations. Our study reports data from a group of Chinese patients consisting of five males and one female with the age of disease onset ranging from 16 to 55 years. The initial symptom in all the patients was the weakness of the lower limbs. Electrophysiological presentations suggested chronic progressive sensorimotor demyelinating polyneuropathy. Overall six mutations were identified in the cohort, including four known mutations [c.103G>T (p.D35Y), c.233C>T (p.S78L), c.293G>A (p.R98H), and c.449-1G>T], and two novel mutations [c.67+4A>G with a mild CMT1B phenotype, and (c.79delG) p.A27fs with a rapidly progressive CMT1B phenotype]. According to the literature review, there are 35 Chinese families with 28 different MPZ mutations. The MPZ mutational spectrum in Chinese patients is very heterogeneous and differs from that of Japanese and Korean individuals, although they do share several common hot spot mutations.

A New Point Mutation in the PMP22 Gene in a Family Suffering From Atypical HNPP

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant inherited disorder commonly presenting with acute-onset, non-painful focal sensory and motor mono neuropathy. In 80% of cases, the genetic defect is a 1.5 Mb deletion on chromosome 17p11.2, including PMP22. Only few cases of partial deletion and point mutations in PMP22 are involved in HNPP. We investigated a 62-years-old man with lower limb plexopathy first considered as Garland’s syndrome. A month later, his 29 years old son also consulted for paresthesia on the peroneal nerve. Targeted sequencing of the PMP22 gene identified a c.370delT (p.Trp124Glyfs*31) in both affected patients. We report a new PMP22 point mutation associated with an atypical clinical phenotype of HNPP, a painful plexopathy of the lower limb worsenen by diabetes and a mere paresthesia, but a typical ENMG. This study illustrates the large spectrum of the disease, and emphasizes the importance of a complete ENMG and family history.

Comparison of clinical and electrophysiological features of patients with hereditary neuropathy with liability to pressure palsies with or without pain

BACKGROUND

Hereditary neuropathy with liability to pressure palsies (HNPP) is a rare neuropathy with a heterogeneous clinical profile. Painless recurrent palsies are the usual presentation, but neuropathic pain could be predominant or inaugural. Browsing the medical literature, we only found two articles reffering to this important clinical feature. Whether there are differences between patients with or without pain is unclear. The main objective of this study was to compare the clinical and electrophysiological features of these patients and to evaluate the impact on their disability.

METHODS

All patients diagnosed with HNPP at the Limoges University Hospital Centre were included and separated into two groups according to the presence or absence of neuropathic pain. In each case, the clinical, genetic, electrodiagnostic, therapeutic features and the modified Rankin Scale (mRS) were evaluated.

RESULTS

Out of 23 patients, 52% presented with neuropathic pain. There was no difference between groups regarding to clinical and electrophysiological features, except for the amplitude of the ulnar sensory nerve (p < 0,003). The amplitudes of sensory nerve action potentials (SNAPs) seemed to be higher in patients with pain, but were below the lower limit of normal. Patients with pain had a higher mRS than patients without pain (p < 0,007).

CONCLUSION

This study supports previous published results and highlights a trend for higher sensory amplitudes in HNPP patients with pain. We found a prevalence of neuropathic pain of 52% in patients with HNPP, underlining the need to systematically assess pain in such patients in order to improve their management.

Three novel mutations in a group of Chinese patients with X-linked Charcot-Marie-Tooth disease

The X-linked form of Charcot-Marie-Tooth disease type1 (CMTX1) is the second most common hereditary motor and sensory neuropathy caused by mutations in the gap junction beta 1 (GJB1) gene. Here, we report the clinical and genetic features of six unrelated Chinese patients with CMTX1, which were identified by genetic analysis. Among the 6 identified mutations, 3 were previously unknown (c.31A > T, c.42 C > G and c.423 del C). The six patients showed typical signs of CMT with a median age of onset of 16.5 years (range: 13-30). Sensorineural hearing loss was confirmed in the patient with the c.423 del C mutation. White matter lesions on brain magnetic resonance imaging (MRI) were observed in two patients. The three newly identified GJB1 mutations expand the clinical and mutational spectrum of CMTX1.