La neurofibromatose 1 (NF1) ou maladie de Von Recklinghausen

Identification of potential common genetic modifiers of neurofibromas: a genome-wide association study in 1333 patients with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is characterized by the highly variable and unpredictable development of benign peripheral nerve sheath tumours: cutaneous (cNFs), subcutaneous (scNFs) and plexiform (pNFs) neurofibromas.

OBJECTIVES

To identify neurofibroma modifier genes, in order to develop a database of patients with NF1.

METHODS

All patients were phenotypically evaluated by a medical practitioner using a standardized questionnaire and the causal NF1 variant identified. We enrolled 1333 patients with NF1 who were genotyped for > 7 million common variants.

RESULTS

A genome-wide association case-only study identified a significant association with 9q21.33 in the pNF phenotype in the discovery cohort. Twelve, three and four regions suggestive of association at the P ≤ 1 × 10-6 threshold were identified for pNFs, cNFs and scNFs, respectively. Evidence of replication was observed for 4, 2 and 6 loci, including 168 candidate modifier protein-coding genes. Among the candidate modifier genes, some were implicated in the RAS-mitogen-activated protein kinase pathway, cell-cycle control and myelination. Using an original CRISPR/Cas9-based functional assay, we confirmed GAS1 and SPRED2 as pNF and scNF candidate modifiers, as their inactivation specifically affected NF1-mutant Schwann cell growth.

CONCLUSIONS

Our study may shed new light on the pathogenesis of NF1-associated neurofibromas and will, hopefully, contribute to the development of personalized care for patients with this deleterious and life-threatening condition.

Plexiform neurofibromatosis of the bladder leading to cystectomy: A rare complication of von Recklinghausen disease

We report a 20-year-old man with neurofibromatosis type 1 presenting with frequent episodes of suprapubic pain. The episodes started 6 months ago, occurred 1 h a day, and were not related to urination. A prostate-sparing cystectomy with orthotopic diversion was performed. Histopathological assessment of the specimen confirmed bladder plexiform neurofibromatosis.

[Clinical aspects of Neurofibromatosis type 1 seen in the Department of Dermatology at University Hospital Antananarivo, Madagascar]

INTRODUCTION

Neurofibromatosis 1 (NF1) is an inherited disease, in an autosomal dominant manner, with complex multi-system involvements. Prevalence varies from one country to another. However, little is known about neurofibromatosis in African countries, particularly in Madagascar.

METHODOLOGY

A descriptive retrospective study from 2014 to 2019 was conducted at the service of dermatology at University Hospital Joseph Raseta Befelatanana in Antananarivo, including all patients with neurofibromatosis according to National Institutes of Health Consensus Conference criteria for whom genealogical investigation could be made.

RESULTS

Among 32 cases of NF1 seen during 6 years, 28 cases were included with a sex ratio M/F of 0.87. The mean age was 24 years ranging from 11 to 54 years. Seventeen patients presented sporadic forms. All patients had "café au lait" spots and cutaneous neurofibromatosis. Three cases presented plexiform neurofibromas which cause significant cosmetic and functional problems by their size and their displayed topography. Fifteen patients had Lisch nodules but no case of optic glioma was identified. Neurological symptoms such as learning difficulties, epilepsy and headache were frequent in our case series. However, access to medical imaging was very limited. Scoliosis was the most common orthopedic complication.

CONCLUSION

The clinical manifestations of NF1 are extremely variable. Although the possibility of systemic complications seems to be low, patients must be followed up.

A case report of malignant peripheral nerve sheath tumour of the left thigh and popliteal fossa with lungs, spleen, and brain dissemination related to neurofibromatosis type 1

A malignant peripheral nerve sheath tumour (MPNST) is a highly aggressive sarcoma. This disease develops in a number of people with neurofibromatosis type 1 (NF1), which is a common genetic disease. The paper presents a patient with typical manifestations of a malignant tumour of the peripheral nerve sheath, in the form of a large tumour of primary localisation in the distal part of the left thigh and left popliteal fossa and with significant dissemination into the lung parenchyma, which was accompanied by respiratory risk. The first operation of the tumour was done four years earlier, after which the patient did not come for regular check-ups. Nine cycles of chemotherapy were performed by Doxorubicin / Ifosfamide / Mesna protocol with clinical improvement and stabilisation, but without a significant impact on the dynamics of the disease and the overall survival was 14 months. It is of utmost importance to early recognise clinical presentation of the malignant form of this tumour and active supervision of a patient with a benign form by experts. In this way, it is possible to apply the optimal treatment modality in a timely manner.

Bone Status According to Neurofibromatosis Type 1 Phenotype: A Descriptive Study of 60 Women in France

There is an increased risk of osteoporosis and an abnormal bone turn over in neurofibromatosis 1 (NF1). Our objective is to evaluate bone status in NF1 and to look for associations with cutaneous phenotype. We conducted a descriptive, monocentric study. We included 60 NF1 women, 18-51 years old, non-menopausal, divided in 2 groups: «at risk phenotype» (ARP) composed by 30 patients with at least 2 subcutaneous neurofibromas (SC-NF) and «classical phenotype» (CP) composed by 30 patients with none or 1 SC-NF. We evaluated low bone mineral density (BMD) risk factors and measured BMD, calcium and phosphorus homeostasis and bone turnover markers. Before 50 years old, Z-score has to be used to assess BMD. Z-score < - 2 is below expected range and represents 2.5% of the population. There was no difference between the two groups. Overall, Z-scores were low and 5 patients had a Z-score < - 2 (8.3%), which is 3 times general population low BMD frequency. 10 fragility fractures occurred in 8 patients, among which 2 were vertebral fractures. 85% had low calcium intake. 12 patients had hypophosphoremia, 25 elevated PTH. Vitamin D levels were low for 86.4%. 41 patients (69.5%) had at least one abnormal bone turnover markers. Low BMD is 3.3 times more frequent in NF1 than in general population, with high fracture risk, regardless of the skin phenotype, classical or at risk, because of high bone turn over and secondary hyperparathyroidism due to vitamin D deficiency and poor calcium intake.

Plexiform neurofibroma with neurofibromatosis type I/ von Recklinghausen's disease: A rare case report

Introduction

Plexiform neurofibroma with neurofibromatosis type 1 (NF1) or Von Recklinghausen's disease is a rare entity and occurs in approximately 5-15% patients. These are slow growing, painless and locally infiltrating tumors. The pattern of inheritance is autosomal dominant and its penetrance is almost complete by 5 years of age.

Presentation of case

We hereby report a case of 13 years old boy visited presenting with swelling of right eyelid and forehead. After surgical removal, the tissue was sent for histopathological evaluation. Microscopy revealed an unencapsulated tumor mass comprising of well organized mixture of multiple nerve bundles with interlacing neural tissue in background of spindle shaped cells along with myxoid areas and numerous blood vessels.

Discussion

The NF1 gene responsible for the disease is located on chromosome 17 at locus 17q11.2 that codes for the protein neurofibromin. The frequency of neomutations is particularly high and almost half of the cases are sporadic. NF1 is characterized by a wide variability of clinical expressions, even within a given family. Majority of patients can be diagnosed only after thorough physical examination.

Conclusion

The wide variation of the clinical expression, the tumor risk and the totally unpredictable evolution of the disease impose regular monitoring of NF1 patients. This surveillance is mainly clinical and has to be adapted to the patient's age in order to assure early management of complications.

[Plexiform cervical neurofibroma: about a case]

Le neurofibrome plexiforme est une tumeur bénigne rare des nerfs périphériques aux dépens des cellules conjonctives du périnevre. Il est pathognomonique de la neurofibromatose de type 1 (NF1 ou maladie de Von Recklinghausen). L'IRM est d'une grande aide au diagnostic de cette pathologie. La confirmation anatomopathologique est parfois nécessaire en particulier en dehors d'un contexte évocateur d'une NF1. Nousrapportonsl'observation d'une petite fille atteinte de neurofibrome plexiforme cervical révélateur d'une neurofibromatose Type 1.

Association of GIST, Breast Cancer and Schwannoma in a 60-Year-Old Woman Affected by Type-1 von Recklinghausen's Neurofibromatosis

Neurofibromatosis (NF1 or von Recklinghausen's disease) is a common autosomal dominant disease associated with a higher incidence of neoplasms than in the general population. We report the case of a 60-year-old woman affected by NF1 who was coincidentally diagnosed with a gastrointestinal stromal tumor, a breast carcinoma and a peripheral nervous system tumor.

[Type 1 neurofibromatosis: Onset of two tumors before the age of 5years]

Neurofibromatosis type 1 (NF1) is a frequent autosomal dominant genetic disorder that predisposes to the development of benign and malignant tumors. Mutation of the NF1 gene affects the RAS-MAPK signaling pathway and leads to a dysfunction in cell proliferation and induces tumor development. Epidemiology of cancer in children with NF1 is very different from the general pediatric population, which requires regular and specific monitoring. Neurofibroma is the most frequent benign tumor. It can be very invalidating depending on the size and location of the tumor. Currently, there is no specific treatment for these tumors. The most frequent malignancies in children with NF1 are leukemias, rhabdomyosarcomas, malignant peripheral nerve sheath tumors and gliomas. The treatment of these tumors should consider the risk of second cancers induced by radio- and chemotherapy. We report on the case of a 5-year-old boy with NF1 developing two tumors.

Neuropsychological evaluation and parental assessment of behavioral and motor difficulties in children with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant multisystem disorder, with large inter and intrafamilial clinical variability and uncertain prognosis. In children with NF1 cognitive disorders, learning difficulties and behavioral problems are common. The present study aims to establish the neuropsychological and behavioral profiles of 78 patients with NF1, aged between 5 and 18 years, and to examine the relationship between these profiles and the transmission of NF1 (sporadic vs. familial), clinical manifestations, and environmental factors. We used several questionnaires completed by parents and neuropsychological tests. The results confirmed specific neuropsychological disabilities in children with NF1, especially involving visuospatial and fine motor skills, learning difficulties and behavioral problems. Cognitive difficulties were significantly more frequent in patients with familial than in those with sporadic NF1. All parental questionnaires were correlated with each other, but parental reports were not associated with FSIQ, SES, school status, and clinical manifestations of the disease. Neuropsychological tests were poorly related to parental reports of cognitive and behavioral difficulties.

[A rare cause of cervical swelling in a child: Solitary plexiform neurofibroma]

Plexiform neurofibroma is a rare benign tumor of the peripheral tissue cells developed in the perineurium. Often considered pathognomonic of neurofibromatosis type 1 (NF1 or von Recklinghausen disease), it can be solitary without NF1, especially in children. The diagnosis is essentially pathological and treatment is primarily surgical to avoid malignant degeneration. We report on a case of cervical solitary plexiform neurofibroma discovered in a 9-year-old child.

[Anxiety disorders in type 1 neurofibromatosis: A case report]

BACKGROUND

Neurofibromatosis type 1 (NF1), also known as Von Recklinghausen disease, is one of the most frequent human genetic diseases, with a prevalence of one case in 3000 births, an autosomal dominant mode of inheritance, and a high rate of new mutations. NF1 has markedly variable clinical expression, with manifestations ranging from mild lesions to several complications and functional impairment. The complications are age-specific. Psychiatric disorders are more frequent in NF1 than in the general population, especially in children. They include dysthymia, depressive mood, anxiety, and personality disorders. Bipolar mood disorders or schizophrenia are rather rare. The majority of studies have focused on physical health and neurocognitive function in NF1, whereas psychiatric disorders associated with this disease remain unclear and poorly documented. This report is based on a clinical case and discusses the relationship between neurofibromatosis type 1 and psychiatric disorders, particularly anxiety disorders.

PRESENTATION OF CASE

This case concerns a 13-year-old girl, the first child of healthy and non-consanguineous parents. The patient's history showed normal psychomotor and psychoaffective development. Her father and paternal grandmother had isolated café-au-lait spots. In June 2013, a subcutaneous mass appeared in her right thigh. She consulted a neurologist and was explored. The physical examination revealed signs of NF1. She had café-au-lait spots on the trunk and extremities, and a neurofibroma in the right thigh. Bilateral ophthalmic examination revealed multiple Lish nodules. After 1 month, a psychiatric consultation was requested for sad mood and night terrors. Obsessive compulsive disorder and generalized anxiety disorder were diagnosed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition.

CONCLUSIONS

The current psychiatric literature does not provide full explanations of anxiety symptoms associated with NF1. Some authors have tried to explain the link between NF1 and psychiatric disorders, and several etiopathogenic hypotheses have been discussed. In our case, a concomitant diagnosis of NF1 and anxiety disorders was made at the age of 13. However, anxiety symptoms started to appear before age 4; they increased gradually and occupied the foreground. This would strengthen the hypothesis of genetic determinism in NF1 patients. The question that arises is: is it a fortuitous association of psychiatric disorders and NF1 or are they psychiatric manifestations induced by a multisystem disease? More detailed investigations are necessary to clarify the etiopathogenic and psychopathological mechanisms that would cause psychiatric comorbidity associated with NF1.

[The bladder involvement in Von Recklinghausen's disease]

La neurofibromatose de type 1 ou maladie de Von Recklinghausen est une maladie génétique autosomique dominante en rapport avec des mutations dans le gène suppresseur de tumeur NF1. L'atteinte uro-génitale au cours de cette maladie est rare et moins de 80 cas ont été rapportés à ce jour dans la littérature mondiale. Les auteurs rapportent un nouveau cas d'atteinte vésicale découverte fortuitement au cours du suivi d'une patiente atteinte de la maladie de Von Recklinghausen. A travers cette observation et une revue de la littérature les auteurs discutent également les difficultés diagnostiques, thérapeutiques ainsi que les modalités de suivi dans cette maladie.

Tumors perturbing extracellular matrix biosynthesis. The case of von Recklinghausen's disease

This is a short review of neurofibromatosis-1 or von Recklinghausen's disease, due to a loss of function mutation of the gene neurofibromin-1, which normally inhibits the Ras MAPK-pathways. Among its symptoms, the strong oversynthesis of several collagen types designates this disease as producing a deregulation of extracellular matrix biosynthesis involved in tumor formation. Up to about 40% of the skin tumors consist of collagens. A short summary of the clinical manifestations and pathological and genetic mechanisms are also described.

Patient with high-risk GIST not associated with c-KIT mutations: same benefit from adjuvant therapy?

A patient was diagnosed with neurofibromatosis type 1 (NF1) and gastrointestinal stromal tumour (GIST). This is not simply a coincidence; numerous molecular and genetic studies have established a close relationship between the two disorders, suggesting that GIST should be included in the clinical spectrum of NF1. In NF1 presenting GIST, the tumour usually develops in the small intestine. We present a 51-year-old woman diagnosed with NF1, who on follow-up showed an intra-abdominal mass. The pathological study of the mass after surgery led to the diagnosis of GIST with no mutations in exons 9, 11, 13 and 17 of the c-KIT gene or in exons 12, 14 and 18 of the platelet-derived growth factor receptor α gene. Imatinib was initiated as coadjuvant therapy with good tolerance, no toxicity and without evidence of relapse during follow-up.

[Management of plexiform neurofibroma isolated in childhood: four patients]

Plexiform neurofibroma is a rare and benign tumor often associated with type 1 neurofibromatosis (NF1) or Von Recklinghausen's disease. Present in one third of cases of NF1, there are isolated forms where the diagnosis should remain a diagnosis of exclusion. We report four cases of isolated plexiform neurofibromas found in children from topographies and we discuss the pretherapeutic assessment, the surgical management and the long-term follow-up.

Childhood orbitotemporal neurofibromatosis masked by congenital glaucoma and buphthalmos

In newborns with unilateral buphthalmos and presumed congenital glaucoma, the differential diagnosis should include the rare condition of orbitotemporal neurofibromatosis. The authors present the diagnostic challenge of an unusual case of neurofibromatosis type 1 with unilateral congenital glaucoma, buphthalmos, and sphenoid-orbital dysplasia. The accompanying type of osseous orbital dysplasia has rarely been described in the literature, complicating the diagnostic and management process.

Vascular Wall Invasion in Neurofibromatosis-Induced Aortic Rupture

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disease primarily characterized by cutaneous café au lait macules, benign neurofibromas, and iris hamartomas. A spectrum of vascular abnormalities is associated with NF-1. We present a case of a 49-year-old female with NF-1 and spontaneous rupture of the infrarenal aorta caused by invasion of a neurofibroma and treated with endovascular stent grafting.

Unidentified bright objects on brain MRI in children as a diagnostic criterion for neurofibromatosis type 1

BACKGROUND

Lesions of the brain denominated as unidentified bright objects (UBOs), which are not included in the diagnostic criteria for neurofibromatosis type 1 (NF1) established by the National Institutes of Health (NIH), have been detected by MRI.

OBJECTIVE

The purpose of this study was to investigate the possibility of including the presence of UBOs as a diagnostic criterion for NF1 in children.

MATERIALS AND METHODS

The study included 88 children between the ages of 2 and 18 years. The case group consisted of 40 children diagnosed with sporadic or familial NF1 according to the criteria established by the NIH. A control group consisted of 48 individuals referred for routine MRI of the brain for other complaints not related to NF1.

RESULTS

UBOs were identified in 70% of the NF1 patients and in none of the control group. The sensitivity of the presence of UBOs for the diagnosis of NF1 was 70% (CI 53-83%), with a false-negative rate of 30% (CI 27-47%), a specificity of 100% (CI 86-100%) and a false-positive rate of 0% (CI 0-14%).

CONCLUSION

Faced with the difficulties in diagnosing NF1 in children and the high frequency and specificity of the presence UBOs identified by MRI in our series, we recommend the inclusion of the presence UBOs as a diagnostic criterion for NF1 in children.

[Difficulties of the management of head and neck neurofibromatosis]

INTRODUCTION

Neurofibromatoses represent a group of 7 diseases having the same cutaneous signs due to a common embryologic origin. The types 1 and 2 are the most frequent and the most studied. Neurofibromatosis type 1 (NF1) or Von Recklinghausen's neurofibromatosis is an autosomal dominantly inherited disease, whose prevalence is 1/4500. The cranio-orbitotemporal lesions exist in 1 to 10% of the cases. Neurofibromatosis type 2 (NF2) is also an autosomal dominantly inherited disease, but is ten times less frequent than the NF1 and is characterized by bilateral vestibular schwannomas (former acoustic neurinomas). The purpose of this work was to detail the clinical features, highlighting the diagnostic and therapeutic difficulties.

MATERIAL AND METHODS

Nine patients managed between 1990 and 2005 were reviewed retrospectively. Eight patients were found carrier of NF1 and one patient carrier of NF2 according to the diagnostic criteria of the 1988's National Institute of Health consensus.

RESULTS

Five women and four men were managed; patient age varied between 13 and 62 years and the mean age was 26 years. Surgical resection of the tumor was carried out among 8 patients with bone reconstruction of the orbit on 3 patients and cutaneous expansion on one other. The results are difficult to appreciate especially that the surgery was iterative. However, all our patients were satisfied with the result and we noted recurrence in a patient presenting a retro-auricular tumor, which filled the external auditory canal requiring a further surgery. The patient having NF2 was treated by neurosurgery and showed a good result.

DISCUSSION

The NF1 manifestations are extremely variable. Facial neurofibromatoses are difficult to control given the presence of soft tissues infiltration and the associated osseous dysplasia. The results are modest and recurrence is frequent. Cancer risks and the disease's completely unpredictable evolution urge a regular and multidisciplinary patient follow-up.

Neurofibromatose de type 1

Neurofibromatosis type 1 (NF1) is often associated with psychiatric disorders, which are more frequent in NF1 than in general population (33% of patients). Dysthymia is the most frequent diagnosis (21% of patients). There is also a high prevalence of depressive mood (7%), anxiety (1-6%), and personality (3%) disorders. The risk of suicide is four times greater than in the general population. Bipolar mood disorders or schizophrenia appear to be rare. The impaired quality of life associated with NF1 may play an important role in the development of psychiatric disorders. Quality of life assessments may help to identify a population at high risk.