Therapeutics for childhood neurofibromatosis type 1 and type 2

Benefits of intervention in the Central Auditory Nervous System in individuals with Neurofibromatosis Type 1

OBJECTIVE

To verify the effectiveness of acoustically controlled auditory training in individuals with Neurofibromatosis Type 1.

METHODS

The sample consisted of individuals with Neurofibromatosis Type 1, randomly distributed into two groups, making up the intervention group: individuals undergoing formal auditory training; and the comparison group: individuals who were not submitted to the intervention. Behavioral assessment of central auditory processing and electrophysiological evaluation, composed by Brainstem Auditory Evoked Potential and Long Latency-P300 Auditory Evoked Potential, were evaluated in three moments of evaluations: initial evaluation, reevaluation and after four months of reevaluation and comparing the performance between the groups.

RESULTS

Better performances in central auditory processing were observed after the formal auditory training in the intervention group with significant differences between the evaluations and performance maintenance four months after the end of the training. Significant differences were observed between the groups in the evaluations after the intervention. The electrophysiological evaluation shows unsystematic variation in the short latency potentials and changes in the long latency potentials with the appearance of the P3 wave after the intervention. The behavioral and electrophysiological evaluation in group that was not submitted to the intervention demonstrated that there is no improvement without the intervention, with deterioration of performance. Significant differences were observed in the behavioral and electrophysiological evaluations, in favor of the group submitted to formal auditory training.

CONCLUSIONS

Formal auditory training is effective in rehabilitation in individuals with Neurofibromatosis Type 1.

DESCRIPTORS/KEYWORDS

Neurofibromatosis 1; Hearing Disorders; Auditory Perceptual Disorders; Acoustic Stimulation; Evoked Potentials, Auditory.

Circular RNA circFAT1(e2) Facilitates Cell Progression through the miR-30e-5P/MYBL2 Pathway in Glioma

Objective

To explore the mechanism of glioma from MYB family genes from the perspective of the circRNA-miRNA-mRNA regulatory network.

Methods

First, the MYB family genes were analyzed by multiple bioinformatics analyses to identify one gene most associated with glioma. Then, the prognostic value and clinical characteristics of the gene were evaluated by bioinformatics analysis and experiments in glioma cells. Next, the target miRNA and circRNA were predicted and verified by dual-luciferase reporter assays. Besides, the functions of target circRNA in glioma were investigated by CCK-8 and Transwell assays. At last, the relation between the screened MYB gene, miRNA, and circRNA in glioma was identified by rescue experiments.

Results

After expression and Cox and survival analysis of six MYB family genes, MYBL2 was identified as the gene most associated with glioma. Then, we found that MYBL2 expression in primary gliomas was higher than those in other histologies, and it had variable expression according to clinical features. Furthermore, MYBL2 knockdown in glioma cells impairs cell growth, invasion, and migration in functional studies. Then, miR-30e-5p and circFAT1(e2) were identified as targets of MYBL2 by bioinformatics prediction and experimental verification. Finally, the relationship between circFAT1(e2), MYBL2, and miR-30e-5p was elucidated by rescue experiments.

Conclusion

circFAT1(e2) could promote glioma development by regulating MYBL2 and miR-30e-5p, and MYBL2 has diagnostic and prognostic values in glioma.

The Genetics and Diagnosis of Pediatric Neurocutaneous Disorders: Neurofibromatosis and Tuberous Sclerosis Complex

Neurofibromatosis (NF) and tuberous sclerosis complex (TSC) are the two most common neurocutaneous disorders, both transmitted as autosomal dominant or, in the case of NF, also as a mosaic condition. The causative genetic mutations in these neurocutaneous disorders can lead to benign skin changes or uninhibited growth and proliferation in multiple organ systems due to the loss of tumor suppression in mitogen-activated protein kinase and mammalian target of rapamycin signaling pathways. Common clinical features in NF include pigmented lesions, known as café au lait patches, neurofibromas, intertriginous freckles (Crowe's sign), and benign fibrous growths, such as hamartomas in multiple organ systems. Common clinical features in TSC include hypopigmented macules, known as ash leaf spots, in addition to neurologic sequelae, such as autism, seizures, and developmental delays. Advances in genetic sequencing technologies have allowed an exponential expansion in the understanding of NF and TSC. Consensus criteria have been established for both diagnoses that can be confirmed in most cases through gene testing. Once diagnosed, the clinical and diagnostic value of disease-specific surveillance include early identification of benign and malignant tumors. Genetic counseling is important for informed reproductive decision-making for patients and at-risk family members. The improvement in understanding of pathways of pathogenic disease development and oncogenesis in both conditions have produced a new series of therapeutic options that can be used to control seizures and tumor growth. Tremendous advances in life expectancy and quality of life are now a reality due to early introduction of seizure control and novel medications. While we lack cures, early institution of interventions, such as seizure control in tuberous sclerosis, appears to be disease-modifying and holds immense promise to offer patients better lives.

Common Neonatal Skin Lesions: Melanocytic Nevi, Pigment Alterations, and Nonmelanocytic Nevi

Birthmarks are common in the healthy population and are generally harmless. Certain presentations, however, raise concern for associated syndromes or potential complications. It is important for pediatricians to be familiar with both harmless and potentially concerning birthmarks. This article discusses congenital melanocytic nevi, café-au-lait macules, hypomelanotic macules, nevus depigmentosus, nevus anemicus, epidermal nevi, and nevus sebaceous, including potential syndromes and complications. [Pediatr Ann. 2019;48(1):e23-e29.].

Rett syndrome: a neurological disorder with metabolic components

Rett syndrome (RTT) is a neurological disorder caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2), a ubiquitously expressed transcriptional regulator. Despite remarkable scientific progress since its discovery, the mechanism by which MECP2 mutations cause RTT symptoms is largely unknown. Consequently, treatment options for patients are currently limited and centred on symptom relief. Thought to be an entirely neurological disorder, RTT research has focused on the role of MECP2 in the central nervous system. However, the variety of phenotypes identified in Mecp2 mutant mouse models and RTT patients implicate important roles for MeCP2 in peripheral systems. Here, we review the history of RTT, highlighting breakthroughs in the field that have led us to present day. We explore the current evidence supporting metabolic dysfunction as a component of RTT, presenting recent studies that have revealed perturbed lipid metabolism in the brain and peripheral tissues of mouse models and patients. Such findings may have an impact on the quality of life of RTT patients as both dietary and drug intervention can alter lipid metabolism. Ultimately, we conclude that a thorough knowledge of MeCP2's varied functional targets in the brain and body will be required to treat this complex syndrome.

Neurofibromatosis Type 2

Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disorder (incidence 1:33 000-40 000) characterized by formation of central nervous system tumors, due to mutation in the NF2 gene on chromosome 22q12. Vestibular schwannomas are the hallmark lesion, affecting 95% of individuals and typically occur bilaterally. Schwannomas commonly occur on other nerves intracranially and in the spinal compartment, along with meningiomas, ependymomas, and gliomas. Although histologically benign, tumors are associated with significant morbidity due to multiple problems including hearing and vision loss, gait abnormalities, paralysis, pain, and seizures. Risk of early mortality from brainstem compression and other complications is significant. Severity of disease is higher when NF2 presents during childhood. Children have a more variable presentation, which can be associated with significant delays in recognition of the condition. Careful examination of the skin and eyes can identify important clinical signs of NF2 during childhood, allowing timely initiation of disease-specific surveillance and treatment. Monitoring for complications comprises clinical evaluation, along with functional testing including audiology and serial neuroimaging, which together inform decisions regarding treatment. Evidence for disease-specific medical treatment options is increasing, nevertheless most patients will benefit from multimodal treatment including surgery during their lifetime. Patient enrolment in international natural history and treatment trials offers the best opportunity to accelerate our understanding of the complications and optimal treatment of NF2, with a view to improving outcomes for all affected individuals.

Reconstruction with soft tissue free flaps for large defects after the resection of giant facial neurofibroma

Giant facial neurofibroma leads to disfigurement and functional and neurological deficits. Surgical resection is the mainstay of treatment and poses a great challenge to the surgeon with regard to the restoration of the defects arising from tumour resection. The cases of three male and three female patients diagnosed with giant facial neurofibroma, who underwent radical resection and reconstruction with soft tissue free flaps between 2008 and 2015, were analyzed retrospectively. Clinical data including patient sex, age, preoperative embolization of the nutrient artery, volume of blood loss, type and size of flaps used for reconstruction, and complications were recorded. Three of the six patients underwent preoperative embolization of the nutrient artery. The average volume of blood loss was 2850ml. Reconstruction was performed with anterolateral thigh flaps in four patients and latissimus dorsi myocutaneous flaps in two patients. All free flap reconstructions were successful. Partial necrosis of the scalp and wound dehiscence occurred in one patient each. All complications were managed successfully. In conclusion, the soft tissue free flap is a good choice for the coverage of defects after giant facial neurofibroma resection. Multi-disciplinary treatment should be strengthened to minimize the risks of complications, as well as improving quality of life.

Proposing the use of dental pulp stem cells as a suitable biological model of neurofibromatosis type 1

PURPOSE

This study aims to propose the dental pulp stem cells (DPSCs) as a model for studying two features related to neurofibromatosis type 1 (NF1), i.e. augmented proliferative capacity and altered osteogenic differentiation.

METHODS

We isolated a DPSC from the pulp of deciduous teeth of a 6-year-old NF1 patient and two other healthy children of similar age. Cell proliferation was assayed by counting with a haemocytometer after successive cell re-plating. In order to compare osteogenic differentiation, we used osteoblast-differentiating medium and quantified alizarin stain, which relates to degree of calcification, and evaluated the expression of osteoblastic markers by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The DPSCs isolated from the NF1 patient displayed a greater rate of proliferation when compared to the control cells. Osteogenic differentiation occurred as expected for both NF1 and control, which concerned cell morphology and expression of osteoblast marker genes ALP, BMP2, BMP4, OCN and SPP1. However, alizarin staining denoted a markedly lower calcification level in the cells from the NF1-diagnosed child, considering that less calcium deposits were visualized under light microscopy and a smaller amount of alizarin could be quantified by spectrophotometry after extraction from the stained cells.

CONCLUSION

DPSCs seem to be useful as a model for studying NF1 and predicting prognosis of patients, since their in vitro behaviour seems to mimic at least two features of this disorder: higher tendency to develop bone abnormalities and neoplastic cell proliferation.

Evaluation of Rett Syndrome Symptom Improvement by Metabolic Modulators in Mecp2-Mutant Mice

Mouse models recapitulate many symptoms of Rett Syndrome, an X-linked disorder caused by mutations in methyl-CpG-binding protein 2 (MECP2). The study of Mecp2-null male mice has provided insight into pathogenesis of the disorder-most recently, dysregulation of cholesterol and lipid metabolism. Perisymptomatic treatment with statin drugs successfully mitigates the effects of this metabolic syndrome, increases longevity, and improves motor function. Described here is a metabolic drug screening protocol and timeline for symptom evaluation in Mecp2-mutant mice. Specifically, mice are treated twice weekly with a compound of interest alongside subjective health assessments, bi-weekly body composition measurements, and blood chemistries. Throughout treatment, behavioral phenotyping tests are carried out at specific time points. This protocol is highly adaptable to other neurological diseases; however, the time for completion depends on the specific mutant model under study. The protocol highlights the use of techniques described in several different Current Protocols in Mouse Biology articles to carry out testing in a preclinical model. Curr. Protoc. Mouse Biol. 3:187-204 © 2013 by John Wiley & Sons, Inc.

A role for metabolism in Rett syndrome pathogenesis: New clinical findings and potential treatment targets

Rett syndrome (RTT), an X-linked neurological disorder caused by mutations in MECP2, may have a metabolic component. We reported a genetic suppressor screen in a Mecp2-null mouse model to identify pathways for therapeutic improvement of RTT symptoms. Of note, one suppressor mutation implied that cholesterol homeostasis was perturbed in Mecp2 null mice; indeed, cholesterol synthesis was elevated in the brain and body system. Remarkably, the genetic effect of downregulating the cholesterol pathway could be mimicked chemically by statin drugs, improving motor symptoms, and increasing longevity in the mouse. Our work linked cholesterol metabolism to RTT pathology for the first time. Both neurological and systemic effects of perturbed cholesterol homeostasis overlap with many RTT symptoms. Here we show in patients that peripheral cholesterol, triglycerides, and/or LDLs may be elevated early in RTT disease onset, providing a biomarker for patients that could be aided by therapeutic interventions that modulate lipid metabolism.

A suppressor screen in Mecp2 mutant mice implicates cholesterol metabolism in Rett syndrome

Mutations in methyl CpG binding protein 2 (MECP2) cause Rett Syndrome, the most severe autism spectrum disorder. Re-expressing Mecp2 in symptomatic Mecp2 null mice dramatically improves function and longevity, providing hope that therapeutic intervention is possible in humans. To identify pathways in disease pathology for therapeutic intervention, a dominant ENU mutagenesis suppressor screen was carried out in Mecp2 null mice. Five suppressors that ameliorate symptoms of Mecp2 loss were isolated. Here we show that a stop codon mutation in squalene epoxidase (Sqle), a rate-limiting enzyme in cholesterol biosynthesis underlies suppression in one line. Subsequently, we show that lipid metabolism is perturbed in the brain and liver of Mecp2 null males. Consistently, statin drugs improve systemic perturbations of lipid metabolism, alleviate motor symptoms and confer increased longevity in Mecp2 mutant mice. The genetic screen therefore points to cholesterol homeostasis as a potential target for the treatment of Rett patients.

Clinical and molecular prognostic predictors of malignant peripheral nerve sheath tumor

OBJECTIVE

Malignant peripheral nerve sheath tumors (MPNST) are relatively rare sarcomas and poorly understood. We sought to find clinicopathological and molecular predictors of survival for Chinese MPNST patients.

METHODS

Clinical information from 146 MPNST patients treated in the Tianjin Medical University Cancer Institute and Hospital was collected and 56 cases of formalin-fixed and paraffin-embedded tissues were available for immunohistochemical examination of expression of hepatocyte growth factor receptor (c-MET), E3 ubiquitin-protein ligase Mdm2 (MDM2), and TP53.

RESULTS

The 5-year tumor-free survival rate was 24 % and the median tumor-free survival time was 25.64 months. The 5-year overall survival rate was 57 % and the median overall survival time was 132.57 months. The expression patterns of c-MET, TP53, and MDM2 were heterogeneous with total positivity rates of 82.1 % (46/56), 55.4 % (31/56), and 73.2 % (41/56), respectively. The univariate analysis not only showed that tumor size, Neurofibromin 1 (NF1) status, the American Joint Committee on Cancer (AJCC) stage, surgery, MDM2 expression, and TP53 expression had significant correlation with the tumor-free survival, but also demonstrated that radiotherapy, chemotherapy, tumor size, and NF1 status had significant correlation with the overall survival. Even though multivariate analysis found no independent prognostic predictor of MPNST, tumor size and NF1 status had significant correlation with the tumor-free survival and overall survival of MPNST patients.

CONCLUSIONS

With this, the largest documented Chinese cohort, our data supply powerful Chinese evidence of the prognostic role of tumor size and NF1 status in MPNST.

Neurofibromatosis type 1 complicated by atypical coarctation of the thoracic aorta

Neurofibromatosis type 1 (NF1) is a relatively common autosomal dominant genetic disorder with a prevalence of 1 in 3,000 (0.03%) at birth. Clinical features are café-au-lait macules, intertriginous freckling, dermal neurofibroma, iris hamartoma (Lisch nodules), and learning disability. NF1 vasculopathy is a serious but underrecognized complication involving the cerebrovascular and cardiovascular systems. The incidence of hypertension in patients with NF1 is around 1% and is associated mainly with renal artery stenosis in children. Only a few cases of thoracic aortic coarctation in association with hypertension and neurofibromatosis have been reported. Here we describe the case of a 4-year-old girl who presented with NF1 and hypertension due to atypical coarctation of the thoracic aorta. The diagnosis of coarctation of the thoracic aorta at the Th5-to-Th6 level was made following catheterization with a pressure gradient of 40 mmHg. The patient underwent surgery comprising resection of the coarctation of the thoracic aorta and graft interposition. On the basis of our findings, annual assessment of blood pressure is advised for patients with NF1.

Increased risk of breast cancer in women with NF1

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder associated with increased risk for neoplasms. Two studies in the United Kingdom have indicated that women with NF1 (particularly women under 50) may also be at increased risk of breast cancer. No such study has been done to date in the United States. Chart review for breast cancer diagnoses was undertaken for 126 women with NF1 followed at Johns Hopkins who were 20 years of age or older. Four of 126 women who met eligibility criteria were diagnosed with breast cancer (3.2% over 15 years). The unadjusted standardized incidence ratio (SIR) for breast cancer in the NF1 population between the ages of 20 and 49 was 2.68 (P = 0.076, 95% CI 0.68-7.29) based on incidence rates of breast cancer in the general population taken from the Surveillance Epidemiology and End Results (SEER) database. The unadjusted SIR for women with NF1 ≥50 was 0.81 (P = 0.84, 95% CI 0.041-4.01). When adjusted for race, the rate of NF1 in the general population and time of diagnosis, the SIR was 4.41 (P = 0.0049, 95% CI 1.12-12.00) for women <50 versus 0.94 (P = 0.95, 95% CI 0.047-4.65) for women ≥50. The trend of a higher-than-expected number of breast cancer cases in women <50 with NF1 agrees with the prior studies from the literature. Cumulatively, the data suggests an increased risk of breast cancer for women with NF1 < 50 years old, implying a need for closer surveillance and the establishment of screening guidelines for this patient population.