Diagnosis Of Hereditary Neuropathy With Liability To Pressure Palsies Research Articles

Hereditary Neuropathy with Liability to Pressure Palsies: A Case Report

Background: Hereditary neuropathy with liability to pressure palsies (HNPP) is an uncommon diagnosis that should be considered in patients with multiple compressive neuropathies. This case reports highlights a relatively rare neuropathy with genetic and occupational predisposition, probably first to be reported in the united arab emirates. Case Presentation: We present the case of a 41 years old male who presented with right hand numbness and weakness. Electrodiagnostic testing revealed multifocal neuropathy. Subsequent genetic testing identified heterogeneous deletion of the PMP22 gene to confirm the diagnosis of HNPP. Conclusions: Hereditary neuropathy with liability to pressure palsies can present as a multifocal neuropathy. Occupational history along with genetic testing plays a pivotal role to make the diagnosis.

Hereditary Neuropathy with Liability to Pressure Palsies Masked by Previous Gunshots and Tuberculosis

Objectives. Although hereditary neuropathy with liability to pressure palsies (HNPP) presents with a distinct phenotype on history, clinical exam, and nerve conduction studies, it may be masked if diagnostic work-up suggests other causes. Case Report. In a 37-year-old male with pseudoradicular lumbar pain, neurological exam revealed sore neck muscles, peripheral facial nerve palsy, right anacusis and left hypoacusis, hemihypesthesia of the right face, mild distal quadriparesis, diffuse wasting, and generally reduced tendon reflexes. He had a history of skull fracture due to a gunshot behind the right ear and tuberculosis for which he had received adequate treatment for 3 years; MRI revealed a disc prolapse at C6/7 and Th11/12. Nerve conduction studies were indicative of demyelinating polyneuropathy with conduction blocks. Despite elevated antinuclear antibodies and elevated CSF-protein, HNPP was diagnosed genetically after having excluded vasculitis, CIDP, radiculopathy, and the side effects of antituberculous treatment. Conclusions. HNPP may manifest with mild, painless, distal quadriparesis. The diagnosis of HNPP may be blurred by a history of tuberculosis, tuberculostatic treatment, hepatitis, and the presence of elevated CSF-protein.

Terminal Latency Index (TLI) Abnormalities in Hereditary Neuropathy with Liability to Pressure Palsies (HNPP)

Introduction: The diagnosis of Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) is frequently missed or delayed because of its clinical and electrophysiological heterogeneity. Nonetheless, electrophysiological criteria were published 15 years ago. Our aim was to highlight the Terminal Latency Index (TLI) disorders by describing the electrophysiological characteristics in patients with HNPP. Methods: All the consecutive patients with the clinical and genetic diagnosis of HNPP due to the 1.5Mb deletion of PMP22 or to others mutation or deletion were included. Motor and sensory conductions were studied using surface electrodes placed near the median, ulnar, fibular, tibial, superficial fibular and sural nerves in accordance with standard techniques. The results were compared with our own laboratory standards. Results: All of the 22 included patients had low TLI in the median, ulnar and peroneal nerves, whereas 6% of the patients had low tibial TLI. The other frequent electrophysiological characteristics were increased distal motor latency and low sensory conduction velocity, especially of the median nerve. Conclusions: TLI abnormalities are almost constant in HNPP, which is a great argument to define HNPP as a distally accentuated myelinopathy. TLI disorders should be added to HNPP electrophysiological criteria to improve their diagnosis accuracy.

Ultrasonographic findings in hereditary neuropathy with liability to pressure palsies

Objectives:The aims of this study were to evaluate the sonographic findings of patients with hereditary neuropathy with liability to pressure palsies (HNPP) and to examine the correlation between sonographic and electrophysiological findings.Methods:Nine patients whose electrophysiological findings indicated HNPP and whose diagnosis was confirmed by genetic analysis were enrolled in the study. The median, ulnar, peroneal, and tibial nerves were evaluated by ultrasonography.Results:We ultrasonographically evaluated 18 median, ulnar, peroneal, and tibial nerves. Nerve enlargement was identified in the median, ulnar, and peroneal nerves at the typical sites of compression. None of the patients had nerve enlargement at a site of noncompression. None of the tibial nerves had increased cross-sectional area (CSA) values. There were no significant differences in median, ulnar, and peroneal nerve distal motor latencies (DMLs) between the patients with an increased CSA and those with a normal CSA. In most cases, there was no correlation between electrophysiological abnormalities and clinical or sonographic findings.Discussion:Although multiple nerve enlargements at typical entrapment sites on sonographic evaluation can suggest HNPP, ultrasonography cannot be used as a diagnostic tool for HNPP. Ultrasonography may contribute to the differential diagnosis of HNPP and other demyelinating polyneuropathies or compression neuropathies; however, further studies are required.

Hereditary Neuropathy with Liability to Pressure Palsies: A Report of Two Cases

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal-dominant disorder characterized by self-limited, recurrent compressive mononeuropathies at common entrapment sites precipitated by trivial injuries. This disorder typically develops in early adulthood. Electrodiagnostic studies revealed diffuse mild demyelinating neuropathies with entrapment over common entrapment sites. Nerve biopsies frequently show segmental demyelination and thickening of the myelin sheath which is mostly caused by 1.5 Mb deletion of the 17p 11.2 site containing the peripheral myelin protein 22 (PMP22) gene on the 17(superscript th) chromosome. This report describes the clinical features, electrodiagnostic studies, and genetic studies of a Taiwanese family. Among the 5 members evaluated, 1 latent and 2 symptomatic cases had generally decreased nerve conduction velocities with further focally decreased conduction velocities or conduction blocks at common entrapment sites. Genetic studies demonstrated deletion of the Charcot-Marie-Tooth type IA sequences in 17p 11.2 in all 3 patients. Our case studies suggested that diagnosis of HNPP can be based on clinical suspicion, positive family history, and electrodiagnostic tests; however final confirmation should be based on genetic study.

Central and Proximal Myelin Damage of Cranial Nerves in Hereditary Neuropathy with Liability to Pressure Palsies

Objective: We have attempted to provide evidence for central and proximal nerve myelin damage of cranial nerves in hereditary neuropathy with liability to pressure palsies (HNPP). Methods: Eight patients with the diagnosis of HNPP, which is due to a heterozygous deletion of PMP22 gene, were investigated consecutively. The results of MRI scans of the brain, evoked potential studies (MEP, VEP, AEP), and reflex studies of the motor and sensory cranial nerves (blink reflex, masseter reflex, jaw-opening reflex) were performed and categorized either as suspicious of myelin damage or normal by means of potential latencies and T2 hyperintensity. The control group for the electrophysiological studies consisted of 48 healthy individuals, matched for age and gender. Results: Four patients showed pathological hyperintense T2 lesions in MRI. MEP studies were suspicious of demyelination in 11/64 measurements (2/135 controls; p<0.0001), evoked potentials showed pathological latencies in 15/42 measurements (9/188 controls; p<0.00001), and finally reflex studies brought up evidence for central as well as peripheral myelin damage in 7 of 24 measurements (4/55 controls; p<0.01). Conclusions: This study provides systematic and significant evidence in a small-sized consecutive population of HNPP patients for functionally relevant myelin damage of the central nervous system and proximal cranial nerves, indicating not only a possible clinical role for diagnosis and prognosis of HNPP, but also a possible role for PMP22 pathology in the central myelin structure in general.

Microsatellite mapping of the deletion in patients with hereditary neuropathy with liability to pressure palsies (HNPP): new molecular tools for the study of the region 17p12 --> p11 and for diagnosis.

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant peripheral neuropathy characterized by recurrent episodes of nerve palsies. We have analyzed 11 microsatellite markers from chromosome 17p12 --> p11 in nine French families with HNPP. The three microsatellites D17S839 (afm200yb12), D17S955 (afm317ygl), and D17S921 (afm191xh12) were localized in the deleted region. In allele segregation analyses, the microsatellite D17S793 (afm165zd4) detected two chromosome 17-linked loci, one of which was deleted in HNPP patients. Using these STR markers, we found that the deletion coincided with the CMT1A/HNPP monomer unit in eight of the nine families. In the remaining pedigree, the deletion lay between the centromeric microsatellite D17S805 (afm234tal) and the telomeric marker D17S922 (afm197xh6), which flank the CMT1A monomer unit. Comparison of these data with the available genetic and physical maps of 17p12 --> p11 shows that this region, which is frequently subject to rearrangement-inducing diseases, such as Smith-Magenis syndrome, Charcot-Marie-Tooth type 1A, and HNPP, presents recombination hot spots. Finally, this study demonstrates the usefulness of the D17S122 (RM11GT) and D17S921 (afm191xh12) microsatellites as tools for the molecular diagnosis of HNPP.

DNA analysis in Finnish patients with hereditary neuropathy with liability to pressure palsies (HNPP).

Hereditary neuropathy with liability to pressure palsies (HNPP) is a dominantly inherited disorder that presents as recurrent mononeuropathies precipitated by apparently trivial traumas. The presence of a deletion in 17p11.2 was analysed in 13 Finnish families with HNPP. The deletion was found in all patients who were neurologically and neurophysiologically confirmed to have HNPP. In the problematic cases the detection of the gene defect is the method of choice in the diagnosis of HNPP. Analysis of DNA can also be used to detect clinically unaffected family members.

Hereditary Neuropathy with Liability to Pressure Palsies Masquerading as Slowly Progressive Polyneuropathy

Hereditary neuropathy with liability to pressure palsies (HNLPP) is a peripheral nerve disorder in which recurrent pressure palsies are associated with pathological swelling ('tomacula') of myelinated nerve internodes. We report a patient with a slowly progressive polyneuropathy associated with substantial slowing of conduction velocities initially suggestive of an acquired or hereditary demyelinating polyneuropathy. However, repeat electrodiagnostic studies demonstrated that conduction slowing and partial conduction block were localized primarily to common sites of nerve compression and entrapment. Sural nerve biopsy revealed multiple tomacula consistent with the diagnosis of HNLPP.