INTRODUCTION

Neurofibromatosis type 1 (NF1) is an autosomal dominantly inherited condition seen in one of 4000 live births, predisposing to peripheral and central neurofibromas. Spinal tumors are seen in 40% of cases with NF1 and only 2% will develop symptoms, and among those who develop symptoms where 33% showed intradural extramedullary location. Thoracic spinal dumbbell neurofibroma is even rarer, and cases that extend to obliterate the posterior mediastinum even more so, with the case presented being the largest in size documented to date.

A 34-year-old female presented since childhood clinical findings consistent with Neurofibromatosis Type I: generalized cafe-au-lait macules, axillary freckling, cutaneous neurofibromas, two iris Lisch nodules identified via slit lamp examination, and anterolateral bowing of the right tibia, and no known parental history of Neurofibromatosis Type I. Prior to admission, the patient presented with progressive loss of motor strength of the lower extremities, and progressive dyspnea. Work-up revealed a Thoracic Intradural Extramedullary Neurofibroma extending to the Right Posterior Mediastinum measuring 15.3 cm x 12.9 cm x 9.7 cm in the thoracic cavity compressing the right lung and bronchus. An extensive two stage surgery was contemplated involving an initial resection of the Intradural mass, with spine instrumentation for support, and subsequent resection of the mediastinal extension. However, complications from the compressing tumor: complete cord transection syndrome causing spinal autonomic dysfunction, lung and airway compromise causing prolonged intubation and difficulty in weaning from mechanical ventilatory support, extensive thrombus formation in the right jugular vein, and nosocomial infections all created compounding difficulties for the surgical technique and anesthetic plan.

Cornerstone management for dumbbell spinal neurofibromas involves their total removal. The best results are obtained in patients showing minimal neurological deficits during the preoperative period. However, little improvement may be expected from patients who develop complete transection syndrome during the postoperative period. Concurrent medical management to prepare the patients are equally important. The multi-subspecialty approach required in managing these cases entails a good balance between the disability before the surgery, anticipated outcomes, and quality of life of the patients.

BACKGROUND

Traumatic peripheral nerve injury (TPNI) is a debilitating condition that may result in significant disability. There is variability in the epidemiology, clinical profile, and mechanism of injury worldwide, but data for low- and middle-income countries (LMICs) such as the Philippines are sparse.

We aimed to determine the demographic and clinical characteristics, management, and outcomes of patients who sustained TPNI in our center.

We performed a retrospective cohort study of all patients referred for TPNI at our institution from 2013 to 2019. Data on demographics, clinical features, etiology, surgical management, and status on last follow-up were collected.

Forty-four patients with injuries to 62 peripheral nerves were included in the cohort, which had a strong male predilection (98%). The mean age at diagnosis was 35.5 years, with 78% of patients aged between 16-45 years. The most common etiologies were laceration due to sharp objects (39%), stab wound (23%), hacking injury (14%), and vehicular crash (14%). In terms of mechanism of nerve injury, the most common was sharp laceration (80%), followed by stretch injury/nerve injury in continuity (14%). The most commonly injured nerves were the ulnar (36%) and median nerves (32%), more often on the right side (66%). Nerve repair surgery was performed in 80% of cases.

TPNIs in a tertiary center in the Philippines most commonly involved young males in the working age group and were caused by occupational and domestic accidents. Appropriate surgical management of TPNI is feasible in low resource settings.

OBJECTIVE: To summarize the gene therapy strategies for neurofibromatosis type 1 (NF1) and related research progress. METHODS: The recent literature on gene therapy for NF1 at home and abroad was reviewed. The structure and function of the NF1 gene and its mutations were analyzed, and the current status as well as future prospects of the transgenic therapy and gene editing strategies were summarized. RESULTS: NF1 is an autosomal dominantly inherited tumor predisposition syndrome caused by mutations in the NF1 tumor suppressor gene, which impair the function of the neurofibromin and lead to the disease. It has complex clinical manifestations and is not yet curable. Gene therapy strategies for NF1 are still in the research and development stage. Existing studies on the transgenic therapy for NF1 have mainly focused on the construction and expression of the GTPase-activating protein-related domain in cells that lack of functional neurofibromin, confirming the feasibility of the transgenic therapy for NF1. Future research may focus on split adeno-associated virus (AAV) gene delivery, oversized AAV gene delivery, and the development of new vectors for targeted delivery of full-length NF1 cDNA. In addition, the gene editing tools of the new generation have great potential to treat monogenic genetic diseases such as NF1, but need to be further validated in terms of efficiency and safety. CONCLUSION Gene therapy, including both the transgenic therapy and gene editing, is expected to become an important new therapeutic approach for NF1 patients.
Humans ; Neurofibromatosis 1/pathology* ; Neurofibromin 1/metabolism* ; GTPase-Activating Proteins ; Mutation ; Genetic Predisposition to Disease ; Genetic Therapy

Background: Vitamin B12 is one of the common drugs used by physicians to treat peripheral neuropathy (PN), although many patients have a good response, however, overdose and toxicity aggravate the condition and worsen the patient’s symptoms. The purpose of this paper is to highlight association between Vitamin B12 toxicity and deterioration of PN symptoms. Case Summary: An elder Sudanese man with acute onset of sensory PN, the patient’s symptoms started by tingling sensations and paresthesia affecting both hands and feet. After patient received cobalamin (vitamin B 12) prescribed by his doctor, the patient symptoms were markedly aggravated and his condition worsened to extend that impaired the normal patient ordinary work. No symptoms related to motor system. Other possible etiologies were studied and excluded. Investigations of his condition revealed blood level of B12 was 1900 pg/mL, the patient condition improved dramatically with discontinuation of the drug. Conclusion Cobalamin toxicity aggravate sensory PN symptoms. Clinicians are advised to adjust the dose and check Cobalamin level before and during treatment to avoid its toxicity.
Peripheral Nervous System Diseases ; Vitamin B 12

Humans ; Herpesvirus 3, Human ; Myelitis, Transverse/complications* ; Guillain-Barre Syndrome/complications* ; Herpes Zoster/complications* ; Varicella Zoster Virus Infection/complications*

OBJECTIVE: To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury. METHODS: Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group. RESULTS: At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm ², which was significantly more than that in group A [(298.33±153.12) cells/mm ²] ( t=6.139, P<0.001). CONCLUSION The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.
Rats ; Animals ; Male ; Rats, Sprague-Dawley ; Polyesters ; Peripheral Nerve Injuries/surgery* ; Elastomers ; Urethane ; Sciatic Nerve/injuries* ; Carbamates ; Nerve Tissue ; Nerve Regeneration/physiology*

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with hereditary spastic paraplegia type 30 (HSP30). METHODS: A proband presented at the Second Hospital of Shanxi Medical University in August 2021 was selected as the study subject. The proband was subjected to whole exome sequencing, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: The proband was found to have harbored a heterozygous c.110T>C variant in exon 3 of the KIF1A gene, which can cause substitution of isoleucine by threonine at position 37 (p.I37T) and alter the function of its protein product. The same variant was not found in his parents, elder brother and elder sister, suggesting that it has a de novo origin. Based on the guidelines of the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic (PM2_Supporting+PP3+PS2). CONCLUSION The c.110T>C variant of the KIF1A gene probably underlay the HSP30 in the proband. Above finding has enable genetic counseling for this family.
Humans ; Male ; East Asian People ; Kinesins/genetics* ; Mutation ; Pedigree ; Spastic Paraplegia, Hereditary/genetics* ; Female

OBJECTIVE: To analyze the clinical phenotype and genetic characteristics of a child with Hereditary spastic paraplegia (HSP). METHODS: A child with HSP who was admitted to the Third Affiliated Hospital of Zhengzhou University on August 10, 2020 due to discovery of tiptoeing for 2 years was selected as the study subject, and relevant clinical data was collected. Peripheral blood samples of the child and her parents were collected for the extraction of genomic DNA. And trio-whole exome sequencing (trio-WES) was carried out. Candidate variants were verified by Sanger sequencing. Bioinformatic software was used to analyze the conservation of variant sites. RESULTS: The child was a 2-year-and-10-month-old female with clinical manifestations including increased muscle tone of lower limbs, pointed feet, and cognitive language delay. Trio-WES results showed that she had harbored compound heterozygous variants of c.865C>T (p.Gln289*) and c.1126G>A (p.Glu376Lys) of the CYP2U1 gene. And the corresponding amino acid for c.1126G>A (p.Glu376Lys) is highly conserved among various species. Based on guidelines from the American College of Medical Genetics and Genomics, the c.865C>T was predicted as a pathogenic variant (PVS1+PM2_Supporting), and c.1126G>A was rated as a variant of uncertain significance (PM2_Supporting+PM3+PP3). CONCLUSION The child was diagnosed with HSP type 56 due to compound variants of the CYP2U1 gene. Above findings have enriched the mutation spectrum of the CYP2U1 gene.
Female ; Humans ; Cytochrome P450 Family 2/genetics* ; Mutation ; Pedigree ; Phenotype ; Spastic Paraplegia, Hereditary/genetics* ; Infant

OBJECTIVES: To explore the changes of elbow flexor muscle strength after musculocutaneous nerve injury and its correlation with needle electromyography (nEMG) parameters. METHODS: Thirty cases of elbow flexor weakness caused by unilateral brachial plexus injury (involving musculocutaneous nerve) were collected. The elbow flexor muscle strength was evaluated by manual muscle test (MMT) based on Lovett Scale. All subjects were divided into Group A (grade 1 and grade 2, 16 cases) and Group B (grade 3 and grade 4, 14 cases) according to their elbow flexor muscle strength of injured side. The biceps brachii of the injured side and the healthy side were examined by nEMG. The latency and amplitude of the compound muscle action potential (CMAP) were recorded. The type of recruitment response, the mean number of turns and the mean amplitude of recruitment potential were recorded when the subjects performed maximal voluntary contraction. The quantitative elbow flexor muscle strength was measured by portable microFET 2 Manual Muscle Tester. The percentage of residual elbow flexor muscle strength (the ratio of quantitative muscle strength of the injured side to the healthy side) was calculated. The differences of nEMG parameters, quantitative muscle strength and residual elbow flexor muscle strength between the two groups and between the injured side and the healthy side were compared. The correlation between elbow flexor manual muscle strength classification, quantitative muscle strength and nEMG parameters was analyzed. RESULTS: After musculocutaneous nerve injury, the percentage of residual elbow flexor muscle strength in Group B was 23.43% and that in Group A was 4.13%. Elbow flexor manual muscle strength classification was significantly correlated with the type of recruitment response, and the correlation coefficient was 0.886 (P<0.05). The quantitative elbow flexor muscle strength was correlated with the latency and amplitude of CMAP, the mean number of turns and the mean amplitude of recruitment potential, and the correlation coefficients were -0.528, 0.588, 0.465 and 0.426 (P<0.05), respectively. CONCLUSIONS The percentage of residual elbow flexor muscle strength can be used as the basis of muscle strength classification, and the comprehensive application of nEMG parameters can be used to infer quantitative elbow flexor muscle strength.
Humans ; Elbow ; Electromyography ; Musculocutaneous Nerve ; Elbow Joint/physiology* ; Muscle, Skeletal ; Muscle Strength ; Peripheral Nerve Injuries

OBJECTIVES: To study the characteristics of vincristine-induced peripheral neuropathy (VIPN) in children with acute lymphoblastic leukemia (ALL) and the factors influencing the development of VIPN. METHODS: The children with ALL, aged 1-18 years, who were treated with CCCG-ALL2015 or CCCG-ALL2020 regimen in the Affiliated Hospital of Guizhou Medical University from January 2018 to February 2022 were enrolled as subjects. According to the influence of age on risk, the children were divided into 1-10 years group with 91 children and >10 years group with 29 children. VIPN was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (5th edition), and the incidence rate, severity, and type of VIPN were compared between different groups. RESULTS: A total of 120 children were enrolled in this study, among whom 56 (46.7%) developed VIPN. The >10 years group had a significantly higher incidence rate of VIPN than the 1-10 years group (69% vs 40%, P<0.05). Among the 56 children with VIPN, 12 (21%) had grade 3 VIPN or above, and 44 (79%) had grade 2 VIPN. There were 77 cases of autonomic nerve symptoms (59.7%), 42 cases of peripheral nerve injury (32.5%), and 10 cases of cranial nerve injury (7.8%). There were no significant differences in the severity and type of VIPN between the groups with different ages, sexes, degrees of risk, or treatment regimens (P>0.05). The results of binary logistic regression analysis showed that age is the influencing factor for the occurrence of VIPN (P>0.05). CONCLUSIONS There is a relatively high incidence rate of VIPN in children with ALL, with the highest incidence rate of autonomic nervous symptoms. The incidence of VIP in children over 10 years old is relatively high.
Child ; Humans ; Antineoplastic Agents, Phytogenic/adverse effects* ; Cohort Studies ; Peripheral Nervous System Diseases/diagnosis* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy* ; Vincristine/adverse effects* ; Infant ; Child, Preschool ; Adolescent