Hereditary neuropathy with liability to pressure palsies in childhood: report of a case and a brief review

Literature review of clinical analysis of hereditary neuropathy with liability to pressure palsies

This review summarizes the clinical and electromyography (EMG) characteristics and peripheral myelin protein 22 (PMP22) gene-related diseases of hereditary neuropathy with liability to pressure palsies (HNPP). Clinical, EMG, and laboratory data of patients diagnosed with HNPP at our institution from 2022 to 2023 were retrospectively reviewed. Relevant literature from January 2003 to June 2024 was retrieved from PubMed using the keywords "hereditary neuropathy with liability to pressure palsies" and "HNPP." Clinical manifestations, EMG characteristics, and gene detection results of HNPP were summarized. All patients exhibited transient neurological symptoms and tested positive for the PMP22 deletion. EMG revealed multiple peripheral nerve abnormalities. Sixty-eight studies meeting the inclusion and exclusion criteria were included, comprising 124 HNPP cases (including six from our study), with 67 males and 57 females. The mean age of onset and diagnosis for the 124 cases were 26.5 ± 18 years and 32.7 ± 18.9 years, respectively, with a maximum onset-to-diagnosis interval of 40 years. Typical weakness and numbness in vulnerable areas were observed in 63.7% of cases, with 62% experiencing recurrent episodes. Atypical symptoms were present in 29.8%, while 6.5% were asymptomatic. Patients exhibited pain and muscular dystrophy (17.7%), pes cavus (12.1%), and a family history of HNPP (64.5%). Among symptomatic patients, triggers were traction or compression (57.8%), temperature changes (3.4%), or unclear (38.8%). Heterozygous PMP22 deletions and other PMP22 gene mutations were found in 77.4% and 22.6% of cases, respectively.

Clinical characteristics of hereditary neuropathy with liability to pressure palsy presenting with monoparesis in the emergency department

Hereditary neuropathy with liability to pressure palsy (HNPP) is a rare neurological genetic disease caused by deletion of the peripheral myelin protein 22 gene and presents in childhood or young adulthood. We report four cases of HNPP with typical and rare presentations, reflecting the broad clinical spectrum of this disease. Two patients presented with mononeuropathies that are frequently observed in HNPP; the remaining two presented with bilateral neuropathy or mononeuropathy anatomically present in the deep layer. This reflects the broad clinical presentation of HNPP, and clinicians should differentiate these conditions in young patients with monoparesis or bilateral paresis. Although HNPP is currently untreatable, early diagnosis in the emergency department can lead to early detection, eventually resulting in less provocation and recurrence which may cause early motor nerve degeneration.

Peripheral nerve injuries in the pediatric population: a review of the literature. Part II: entrapment neuropathies

INTRODUCTION

Entrapment neuropathies are infrequent in children, and therefore remain unrecognized. The incidence of radial, median, and cubital mononeuropathies are all similar. Despite the rarity of such cases, extensive, albeit scattered, literature has accumulated concerning entrapment neuropathies in children.

OBJECTIVE

To the literature concerning entrapment neuropathies in children.

METHODS

A systematic review of the existing literature has been made.

RESULTS

The management of chronic pediatric pain is very important in such patients to prevent youths from experiencing prolonged absences from school, sports, or other productive activities, and limit the psychological burden of chronic disease. Nonsurgical treatment of both cubital and carpal tunnel syndromes has been disappointing in pediatric patients, with only limited success; and, to date, there is no clear explanation for the outcome differences generated by nonsurgical management between adults and youths. Simple decompression of the ulnar nerve at the elbow also has much higher rates of failure in children than in adults.

CONCLUSIONS

The presence of an entrapment neuropathy (specially carpal tunnel syndrome) in a pediatric-age patient should alert medical care providers to the potential of some underlying genetic condition or syndrome.

Hereditary neuropathy with liability to pressure palsies in childhood: Case series and literature update

Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) is a rare condition in childhood with a diverse range of clinical presentations. We analyzed the clinical presentation and electrophysiological data of 12 children with a confirmed PMP22 gene deletion and reviewed the published reports of HNPP in children and compared our data with the reports from the literature review. Peroneal palsy was the most common presentation (42%) followed by brachial plexus palsy in 25% of our cases. Nerve conduction studies were always suggestive of the diagnosis demonstrating 3 major patterns: multifocal demyelination at the area of entrapment, generalized sensory-motor polyneuropathy and a combination of the two first patterns in a vast majority (60%). Surprisingly, there was bilateral or unilateral electrophysiological entrapment of the median nerve at the carpal tunnel in all our patients. The clinical presentation of HNPP in childhood is heterogeneous and electrophysiological findings are helpful in establishing the diagnosis. Any unexplained mononeuropathy or multifocal neuropathy should lead to PMP22 gene testing to look for the deletion. Early diagnosis is important in order to facilitate appropriate genetic counseling and also for the appropriate care for these patients.

Partial Gene Deletions of PMP22 Causing Hereditary Neuropathy with Liability to Pressure Palsies

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal neuropathy that is commonly caused by a reciprocal 1.5 Mb deletion on chromosome 17p11.2, at the site of the peripheral myelin protein 22 (PMP22) gene. Other patients with similar phenotypes have been shown to harbor point mutations or small deletions, although there is some clinical variation across these patients. In this report, we describe a case of HNPP with copy number changes in exon or promoter regions of PMP22. Multiplex ligation-dependent probe analysis revealed an exon 1b deletion in the patient, who had been diagnosed with HNPP in the first decade of life using molecular analysis.

Hereditary neuropathy with liability to pressure palsies presenting with sciatic neuropathy

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal-dominant disorder associated with recurrent mononeuropathies following compression or trivial trauma. Reports on sciatic neuropathy as the presenting manifestation of HNPP are very scarce. We report on a 21-year-old previously healthy man who was admitted with sensorimotor deficits in his left leg. He had no history of preceding transient episodes of weakness or sensory loss. Clinical and electrophysiological examinations were consistent with sciatic neuropathy. Cerebrospinal fluid investigation and MRI of the nerve roots, plexus, and sciatic nerve did not indicate the underlying aetiology. When extended electrophysiological tests revealed multiple subclinical compression neuropathies in the upper limbs, HNPP was contemplated and eventually confirmed by genetic testing.

[Acute motor deficit in childhood: diagnosis management]

Acute motor deficit is not uncommon in childhood, with various neurological etiologies. Pertinent semiological analysis allows correct diagnosis management, with adequate paraclinical investigations. The authors describe this clinical diagnosis strategy. The most common clinical situations and various etiologies are presented; paraclinical investigations confirming the diagnosis are discribed, with specific attention to central nervous system imaging according to the most recent sequences.

Hereditary neuropathy with liability to pressure palsy (HNPP) in childhood: a case study emphasizing the relevance of detailed electrophysiological examination for suspected HNPP in the first decade

Hereditary neuropathy with liability to pressure palsy (HNPP) is an autosomal dominant disorder characterized by recurrent mono-neuropathies secondary to minor trauma or compression. Whilst typical episodes of palsy generally become apparent during the second and the third decades, HNPP is rarely diagnosed in the first decade. We present the case of a 6-year-old patient to draw attention to the possibility of HNPP attacks in the first decade and the importance of detailed electrophysiological examination.

[Hereditary neuropathy with liability to pressure palsies (HNPP) in hand surgery: reminds and warn against a usually unrecognised disease]

Tomacula is a rare hereditary disease due to a deletion on chromosome 17. Clinical presentation varies but patients usually complain of recurrent paraesthesiaes and palsies related to compression or trauma of a peripheral nerve. Diagnosis is based on electrophysiological studies, nerve biopsies and genetic tests. Implications for the patient and family members are a genetic counselling and some simple preventive measures. Although there is no curative treatment for this neuropathy, surgery can be useful for decompression of nerves and neurolysis. However, the surgical act increases the risk of nerve damage. Knowing about the diagnosis can help the patient and the surgical team avoid causing lesions.