Advances in Molecular Diagnosis of Neurofibromatosis Type 1

Early-life immune activation is a vulnerability factor for adult epileptogenesis in neurofibromatosis type 1 in male mice

Introduction

Patients with Neurofibromatosis type 1 (NF1), the most common neurocutaneous disorder, can develop several neurological manifestations that include cognitive impairments and epilepsy over their lifetime. It is unclear why certain patients with NF1 develop these conditions while others do not. Early-life immune activation promotes later-life seizure susceptibility, neurocognitive impairments, and leads to spontaneous seizures in some animal models of neurodevelopmental disorders, but the central nervous system immune profile and the enduring consequences of early-life immune activation on the developmental trajectory of the brain in NF1 have not yet been explored. We tested the hypothesis that early-life immune activation promotes the development of spatial memory impairments and epileptogenesis in a mouse model of NF1.

Methods

Male wild-type (WT) and Nf1+/- mice received systemic lipopolysaccharide (LPS) or saline at post-natal day 10 and were assessed in adulthood for learning and memory deficits in the Barnes maze and underwent EEG recordings to look for spontaneous epileptiform abnormalities and susceptibility to challenge with pentylenetetrazole (PTZ).

Results

Whereas early-life immune activation by a single injection of LPS acutely elicited a comparable brain cytokine signature in WT and Nf1+/- mice, it promoted spontaneous seizure activity in adulthood only in the Nf1+/- mice. Early-life immune activation affected susceptibility to PTZ-induced seizures similarly in both WT and Nf1+/-mice. There was no effect on spatial learning and memory regardless of mouse genotype.

Discussion

Our findings suggest second-hit environmental events such as early-life immune activation may promote epileptogenesis in the Nf1+/- mouse and may be a risk-factor for NF1-associated epilepsy.

Malignant Peripheral Nerve Sheath Tumors-A Comprehensive Review of Pathophysiology, Diagnosis, and Multidisciplinary Management

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas (STS) with nerve sheath differentiation and a tendency to metastasize. Although occurring at an incidence of 0.001% in the general population, they are relatively common in individuals with neurofibromatosis type 1 (NF1), for whom the lifetime risk approaches 10%. The staging of MPNSTs is complicated and requires close multi-disciplinary collaboration. Their primary management is most often surgical in nature, with non-surgical modalities playing a supportive, necessary role, particularly in metastatic, invasive, or widespread disease. We, therefore, sought to provide a comprehensive review of the relevant literature describing the characteristics of these tumors, their pathophysiology and risk factors, their diagnosis, and their multi-disciplinary treatment. A close partnership between surgical and medical oncologists is therefore necessary. Advances in the molecular characterization of these tumors have also begun to allow the integration of targeted RAS/RAF/MEK/ERK pathway inhibitors into MPNST management.

Mutation spectrum of the NF1 gene and genotype-phenotype correlations in Turkish patients: Seventeen novel pathogenic variants

OBJECTIVE

Neurofibromatosis type 1 is one of the most common autosomal dominant diseases caused by heterozygous mutation in the NF1 gene. Wide spectrum of NF1-related clinical manifestations and mutation distribution makes genetic counselling difficult.

METHODS

The study enrolled 58 unrelated Turkish patients with clinically suspected NF1 referred to the Department of Medical Genetics. Individuals were eligible if they 1) met at least two of the main National Institutes of Health criteria or 2) had multiple café-au-lait macules as a child.

RESULTS

Fourty-one different disease-causing variants were identified in 42 (72.4%) individuals, including 17 novel variants. Twenty-four (58.2%) of the NF1 patients had de novo variants. Café-au-lait macules were observed in all patients (100%). Intracranial hamartoma was the second most common phenotype, found in 52.3% (22/42) of the patients. Other common manifestations were neurofibromas (35.7%), axillary or inguinal freckling (28.5%), and Lisch nodules (28.5%). Additionally, one patient had intra-abdominal malignant peripheral nerve sheath tumours and another patient underwent surgery for serous papillary ovarian cancer.

CONCLUSION

In conclusion, this study is one of the largest studies from Turkey to investigate the NF1 mutation spectrum and genotype-phenotype correlations.

Deletion of the whole NF1 gene in a three-generation family with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder characterized by café-au-lait macules (CALMs), skinfold freckling, Lisch nodules, and neurofibromas. It is associated with heterozygous mutations in the neurofibromatosis type 1 (NF1) gene. Whole NF1 deletion has been described in some cases, but most cases are sporadic, and familial forms are extremely rare. To date, only two-generation familial forms have been described.

OBJECTIVE

To describe a whole NF1 gene deletion in a three-generation family with neurofibromatosis type 1.

METHODS

Physical examinations, laboratory tests, structural neuroimaging studies, whole-exome sequencing, and multiplex ligation-dependent probe amplification analysis were carried out.

RESULTS

All the affected individuals within this three-generation family, including the 14-year-old female proband, her 40-year-old father, and 63-year-old grandmother, exhibited such typical manifestations of NF1 as CALMs and cutaneous neurofibromas, CALMs increased in size with age. The affected subjects had more localized hyperpigmentation and CALMs within the lesion areas, mainly in the chest, abdomen, waist, and back. In addition, learning disorder was observed in the proband, and brain MRI revealed abnormal high signal lesions in the brainstem. All the affected subjects had normal birth history and had no significant past medical history. Whole-exome sequencing and subsequent multiplex ligation-dependent probe amplification analysis identified deletion of the whole NF1 gene, co-segregating with the NF1 phenotype in an autosomal dominant pattern.

CONCLUSIONS

Our findings are the first to identify whole NF1 deletion in a three-generation family with autosomal dominant NF1 and broaden the understanding of the genetic spectrum of NF1-associated NF1.

Type I Neurofibromatosis: Case Report and Review of the Literature Focused on Oral and Cutaneous Lesions

Neurofibromatosis type 1 (NF1) is a common genetic disease whose dermatological lesions are at the forefront of its development. Cutaneous manifestations include café au lait spots, intertriginous freckling, and neurofibromas which appear during childhood and adolescence and are part of the clinical criteria to diagnose NF1. However, it is only recently that oral manifestations have been highlighted in many studies as frequently associated to NF1. This article aims to review oral and cutaneous manifestations related to NF1 and to report a case of a 51-year-old male with skin and oral neurofibromas related to NF1. Our patient presented with lesions on the gingiva, a rare localization that takes a hypertrophic form mimicking other various pathological conditions. Although not frequent, malignant transformation in NF1, especially regarding plexiform neurofibromas, is well established. Patients with NF1 therefore have regular follow-ups based on clinical examination, as sarcomatous transformation brings an extremely poor prognosis, recurrences and distant metastasis being common.

Identification of NF1 Frameshift Variants in Two Chinese Families With Neurofibromatosis Type 1 and Early-Onset Hypertension

Background: Neurofibromatosis type 1 (NF-1) is a common autosomal dominant disorder caused by mutations in the NF1 gene. It is characterized by multiple café-au-lait macules, cutaneous neurofibromas, optic glioma, Lisch nodules, and axillary and inguinal freckling. The aim of this study was to investigate NF1 mutations in two Chinese families with NF-1 who presented with early-onset hypertension, and to determine the prevalence of hypertension associated with NF-1 to better understand this complication. Methods: Whole-exome sequencing was performed for the probands with NF-1 from two unrelated families. Possible pathogenic mutation was predicted by bioinformatic tools. Sanger sequencing was used to confirm candidate variants in all available individuals for familial co-segregation analysis. We also performed a systematic literature review of studies that reported the prevalence of hypertension in patients with NF-1. Results: In family 1, a recurrent mutation c.6789_6792delTTAC in NF1 was identified in the proband but in no other family members, indicating that this is a de novo mutation. In family 2, a novel mutation c.6934_6936delGCAinsTGCT in NF1 was detected in the proband and two other family members, which co-segregated with the disease phenotype within the family. Both mutations were predicted to be pathogenic by bioinformatic analysis. We found hypertension was a relatively common complication of NF-1, with a prevalence range of 6.1-23.4%. Ambulatory blood pressure monitoring is a stable method for detecting initial alterations of the blood pressure pattern, particularly for pre-hypertension. Conclusions: We identified one recurrent (c.6789_6792delTTAC) and one novel frame-shift mutation (c.6934_6936delGCAinsTGCT) in two unrelated families with NF-1 using whole-exome sequencing. In consideration of phenotypic heterogeneity in NF-1, genetic testing is a robust tool which helps early and accurate diagnosis. Because hypertension is not a rare complication of NF-1, routine screening for hypertension in patients with NF-1, especially children and adolescents, is important to avoid serious cardiovascular events.

Ante-natal counseling in phacomatoses

OBJECTIVES

Phacomatoses are a group of neuro-oculo-cutaneous syndromes/ neurocutaneous disorders, involving structures arising from the embryonic ectoderm. Most of phacomatoses including the most common ones:, neurofibromatosis type I and type II (NF1, NF2) and tuberosclerosis complex (TSC), are autosomal dominant genetic disorders with full penetrance and variable expression. As no effective treatment exists, the only way to prevent the disease, is by prenatal genetic diagnosis (either chorionic villus sampling-CVS or amniocentesis-AC) and termination of pregnancy or performing preimplantation genetic testing (PGT). As the risk for an affected offspring is 50% in every pregnancy of an affected parent, prenatal, and preimplantation testing are of great importance. However, those procedures are associated with technical and ethical concerns. This chapter shortly reviews the common phacomatoses emphasizes their genetics and inheritance. We will review the common methods for prenatal and preimplantation diagnoses and discuss its use in common phacomatoses.

CONCLUSION

Phacomatoses are common autosomal dominant genetic conditions with variable expression. Ante-natal genetic diagnosis is an appropriate approach for family planning in individuals affected by phacomatosis or parents of an affected child.

Brain-wide structural and functional disruption in mice with oligodendrocyte-specific Nf1 deletion is rescued by inhibition of nitric oxide synthase

This study assessed the effects of myelin decompaction on motor behavior and brain-wide structural and functional connectivity, and the effect of nitric oxide synthase inhibition by N-nitro-l-arginine methyl ester (L-NAME) on these imaging measures. We report that inducible oligodendrocyte-specific inactivation of the Nf1 gene, which causes myelin decompaction, results in reduced initial motor coordination. Using diffusion-based magnetic resonance imaging (MRI), we show reduced myelin integrity, and using functional MRI, we show reduced functional connectivity in awake passive mice. L-NAME administration results in rescue of the pathology at the mesoscopic level, as measured using imaging procedures that can be directly applied to humans to study treatment efficacy in clinical trials.

Neurofibromin gene (NF1) mutation causes neurofibromatosis type 1 (NF1), a disorder in which brain white matter deficits identified by neuroimaging are common, yet of unknown cellular etiology. In mice, Nf1 loss in adult oligodendrocytes causes myelin decompaction and increases oligodendrocyte nitric oxide (NO) levels. Nitric oxide synthase (NOS) inhibitors rescue this pathology. Whether oligodendrocyte pathology is sufficient to affect brain-wide structure and account for NF1 imaging findings is unknown. Here we show that Nf1 gene inactivation in adult oligodendrocytes (Plp-Nf1^fl/+ mice) results in a motor coordination deficit. Magnetic resonance imaging in awake mice showed that fractional anisotropy is reduced in Plp-Nf1^fl/+ corpus callosum and that interhemispheric functional connectivity in the motor cortex is also reduced, consistent with disrupted myelin integrity. Furthermore, NOS-specific inhibition rescued both measures. These results suggest that oligodendrocyte defects account for aspects of brain dysfunction in NF1 that can be identified by neuroimaging and ameliorated by NOS inhibition.

Identification of a Novel NF1 Frameshift Variant in a Chinese Family with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a progressive neurocutaneous disorder in humans, mainly characterized by café-au-lait macules (CALMs) and neurofibromas. NF1 is caused by variants of the neurofibromin 1 gene (NF1), which encodes a Ras-GTPase-activating protein called neurofibromin. NF1 variants may result in loss of neurofibromin function and elevation of cell proliferation and tumor formation. In this study, a Chinese NF1 family with an autosomal dominant inheritance pattern was recruited. Exome sequencing and Sanger sequencing were performed to discover the causative variant responsible for the family, followed by molecular analysis of effect of the mutated NF1 protein on Ras activity. A novel frameshift variant c.541dupC (p.(Gln181Profs∗20)) in the NF1 gene was identified in all three affected family members. The variant cosegregated with the disease phenotypes in the pedigree and was absent in 100 healthy controls. Bioinformatic analysis showed that the variant c.541dupC (p.(Gln181Profs∗20)) was pathogenic. The further molecular analysis verified the cells expressing NF1 variant p.(Gln181Profs∗20) partially enhanced Ras activity and elevated cell proliferation and tumor formation due to loss of neurofibromin function caused by the variant. Taken together, the data strongly advocate the c.541dupC (p.(Gln181Profs∗20)) variant as the underlying genetic cause of the Chinese family with NF1. Moreover, our findings broaden the spectrum of NF1 variants and provide molecular insights into the pathogenesis of NF1.

Supernumerary teeth of permanent dentition in patients with neurofibromatosis type 1

PURPOSE

The purpose of the study was the investigation of supernumerary teeth (ST) in the permanent dentition of patients with neurofibromatosis type 1 (NF1).

MATERIAL AND METHODS

The panoramic radiographs of 200 NF1 patients were analysed for ST. The potential impact of certain neurogenic facial tumours on the measured variable was investigated separately. The results were compared to dental findings in panoramic radiographs of 200 age- and sex-matched controls.

RESULTS

The total number of ST in all individuals was 23 in 12 patients (3% of total population). However, all ST had developed in the group of NF1 patients (6%), (p = 0.0004). ST were particularly common distal to the molar region. Although ST occur in the region of facial plexiform neurofibroma, the numerical aberrations of the dentition are independent of specific type of facial nerve sheath tumour.

CONCLUSION

The unusual accumulation of ST in the terminal sections of molar development could be an indicator of preferred points of developmental disorder, in which the genetic predisposition of the patient is involved. Reviewing the results of other NF1 patient collectives is desirable.

Surgical Management of "Kissing" Spinal Plexiform Neurofibromas in Neurofibromatosis Type 1 Patients

BACKGROUND

"Kissing" neurofibromas (KNs) are a unique group of spinal tumors found in neurofibromatosis type 1 (NF1) patients. These are bilateral neurofibromas that approximate each other at the same level, with significant impingement compression of the cord or thecal sac. The best management options and surgical strategies for NF1 patients with KN have not been standardized.

METHODS

We conducted a retrospective study evaluating adult NF1 patients with KN. All patients are followed routinely at the Gilbert Israeli NF Center. Patients' files were reviewed for natural history, imaging features, surgical technique, and surgical outcome.

RESULTS

Twelve patients with at least 1 pair of KN were identified (6 females). Median age at spinal presentation was 24 (range 17-48). KNSs were located at the cervical (n = 8) and lumbar (n = 8) region, with no thoracic involvement. Seven of the 12 patients were operated; all underwent surgery due to cervical compression with progressive myelopathy. Four patients remained asymptomatic during the follow-up period. Three patients underwent multiple operations. Operative outcome was favorable in 71% of patients, with marked overall motor improvement or stabilization of neurologic deterioration. Two patients who entered surgery with a low functional reserve deteriorated after surgery.

CONCLUSIONS

In our series, KN caused progressive cord compression in 7 of the 8 patients with cervical tumors. No intervention was needed for lumbar tumors. Cervical tumors should be followed closely, with a low threshold for intervention. NF1 patients harboring KN should be followed both clinically and radiologically for life.

Clinical Presentation and Novel Pathogenic Variants among 68 Chinese Neurofibromatosis 1 Children

Background: Neurofibromatosis 1 (NF1) is one of the most common dominantly inherited genetic disorders worldwide, with an age-dependent phenotypic expression. Exploring the mutational spectrum and clinical presentation of NF1 patients at different ages from a diverse population will aid the understanding of genotype–phenotype correlations. Methods: In this study, 95 Chinese children with clinical suspicion of NF1 mainly due to the presence of multiple café-au-lait macules (CALMs) were subjected to medical exome-sequencing analysis and Sanger confirmation of pathogenic variants. Clinical presentations were evaluated regarding dermatological, ocular, neurological, and behavioral features. Results: Pathogenic or likely pathogenic NF1 variants were detected in 71.6% (68/95) of patients; 20 pathogenic variants were not previously reported, indicating that Chinese NF1 patients are still understudied. Parental Sanger sequencing confirmation revealed 77.9% of de novo variants, a percentage that was much higher than expected. The presence of a higher number of NF1-related features at young ages was correlated with positive diagnostic findings. In addition to CALMs, neurological and behavioral features had a high expression among Chinese NF1 children. We attempted to correlate short stature with the locations of the pathogenic variants across the NF1 gene. It is interesting to notice that variants detected in the C-terminal region of the NF1 gene were less likely to be associated with short stature among the NF1 patients, whereas variants at the N-terminal were highly penetrant for the short stature phenotype. Conclusion: Novel NF1 pathogenic variants are yet to be uncovered in under-studied NF1 patient populations; their identification will help to reveal novel genotype–phenotype correlations.

Two Novel NF1 Pathogenic Variants Causing the Creation of a New Splice Site in Patients With Neurofibromatosis Type I

Neurofibromatosis type I (NF1) is one of the most common autosomal dominant disorders, since the estimated incidence is one in 3,500 births. In this study, we present bioinformatical and functional characterization of two novel splicing NF1 variants, detected in NF1 patients. Patient 1, carrying NF1:c.122A>T, which introduces a new exonic 5' donor splice site, was diagnosed with hormone-positive, Her-2-negative breast cancer at the age of 47. She had an atypical presentation of NF1, with few café-au-lait spots and no Lisch nodules. Patient developed a hemothorax due to subclavian artery rupture, which has previously been described as an extremely rare complication of NF1. Patient 2, carrying NF1:c.7395-17T>G that creates a new intronic 3' acceptor splice site, had quite a typical clinical presentation of NF1: formations on her tongue in the region of her left metacarpal bones and on her left foot, plexiform neurofibroma in her pelvis, several café-au-lait spots, and axillary freckling. She was also diagnosed with cognitive impairment. In the report, we are presenting two novel variants which were successfully classified based on NGS and mRNA analysis. Based on results of mRNA analysis, both variants were classified as likely pathogenic according to ACMG guidelines applying evidence categories PS3, PM2, PP3, and PP1 supporting. By characterizing those two novel NF1 splicing variants, we have confirmed the neurofibromatosis type I phenotype in the two probands.

Genetic Evaluation of Common Neurocutaneous Syndromes

The neurocutaneous syndromes are a group of multisystem disorders that affect the skin and central nervous system. Neurofibromatosis 1, neurofibromatosis 2, tuberous sclerosis complex, and Sturge-Weber syndrome are the four major neurocutaneous disorders that mainly present in childhood. In this review, we discuss the clinical findings and genetic diagnosis, related genes/pathways and genotype-phenotype correlations of these four neurocutaneous syndromes.

Accurate Classification of NF1 Gene Variants in 84 Italian Patients with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant genetic diseases. It is caused by mutations in the NF1 gene encoding for the large protein, neurofibromin. Genetic testing of NF1 is cumbersome because 50% of cases are sporadic, and there are no mutation hot spots. In addition, the most recognizable NF1 clinical features—café-au-lait (CALs) spots and axillary and/or inguinal freckling—appear early in childhood but are rather non-specific. Thus, the identification of causative variants is extremely important for early diagnosis, especially in paediatric patients. Here, we aimed to identify the underlying genetic defects in 72 index patients referred to our centre for NF1. Causative mutations were identified in 58 subjects, with 29 being novel changes. We evaluated missense and non-canonical splicing mutations with both protein and splicing prediction algorithms. The ratio of splicing mutations detected was higher than that reported in recent patients’ series and in the Human Gene Mutation Database (HGMD). After applying in silico predictive tools to 41 previously reported missense variants, we demonstrated that 46.3% of these putatively missense mutations were forecasted to alter splicing instead. Our data suggest that mutations affecting splicing can be frequently underscored if not analysed in depth. We confirm that hamartomas can be useful for diagnosing NF1 in children. Lisch nodules and cutaneous neurofibromas were more frequent in patients with frameshifting mutations. In conclusion, we demonstrated that comprehensive in silico analysis can be a highly specific method for predicting the nature of NF1 mutations and may help in assuring proper patient care.

Endovascular management of renal artery aneurysms induced by neurofibromatosis type 1: A case report

RATIONALE

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disorder characterized by cafe au lait macules and neurofibromatosis. Renal artery aneurysms are relatively uncommon. Endovascular techniques are effective in treating renal aneurysms but successful cases are rarely reported in NF-1 adults.

PATIENT CONCERNS

The patient was one 23-year-old female presented with hypertension, multiple café-au-lait spots ≥15 mm, and plexiform neurofibroma. Renal artery aneurysms were found by ultrasound.

DIAGNOSES

NF-1 was diagnosed based on clinical manifestations and confirmed by gene test. Renal artery aneurysms were diagnosed based on computed tomography.

INTERVENTIONS

Bilateral renal artery angiography was performed and 3 aneurysms were found sequentially on the left anterior superior segmental artery. Microcoil embolization of aneurysms was undertaken.

OUTCOMES

The patient's blood pressure decreased after the procedure with reduction of medicine. A 3-month follow-up unilateral selective renal angiogram demonstrated little change in size of aneurysms, and no opacification of the aneurysmal sac was found. Serum creatinine remained in normal range at 3-month.

LESSONS

Successful endovascular treatment for NF-1 related renal artery aneurysms in adults is reported for the 1st time with preserved renal function and improved hypertension. Endovascular procedure is considered to be feasible and effective for renal artery aneurysms induced by NF-1.

Sella turcica measurements on lateral cephalograms of patients with neurofibromatosis type 1

The aim of this study was to measure line segments and areas of sella turcica on lateral cephalograms with respect to the clinical diagnosis of facial phenotype of patients with neurofibromatosis type 1 (NF1). Special attention was given to correlate the measured values with certain tumour types that are typical for this disease.

Material and methods: Lateral cephalograms of 194 individuals were investigated. Patients with NF1 were further divided according to the detection and topography of facial plexiform neurofibromas (PNF) taking into account the distribution pattern of the trigeminal nerve. All patients with PNF showed unilateral tumour localisation. Patients without any facial PNF constituted a separate group. Healthy volunteers with ideal occlusion and no history of any intervention in the maxillofacial region served as a control group. The following items were determined on the radiographs: sella entrance, sella width, sella depths, sella diagonal, and sella area.

Results: Patients with PNF of the first and second trigeminal nerve branch or affected in all branches showed highly statistically significant enlarged sella tucica measurement values. On the other hand, patients with PNF restricted to one branch only or simultaneously in the second and third branches showed measurement values that were not different to those obtained in NF1 patients devoid of facial PNF. The latter group also showed no difference of sella turcica parameters obtained in the control group.

Conclusion: This study provides evidence for the association of a certain NF1 phenotype with distinct skeletal alterations of the skull base, shown here using the example of the representation of the sella turcica in the lateral radiograph. These findings are also relevant in the discussion of NF1 as a disease of bones and in the assessment of brain development in NF1. Both items are discussed in relationship to a facial plexiform neurofibroma. Furthermore, the knowledge of this association of findings provides the clinician with relevant information in the planning of skull base procedures in these patients.

Mutation spectrum of NF1 gene in Italian patients with neurofibromatosis type 1 using Ion Torrent PGM™ platform

Neurofibromatosis type 1 (NF1) is caused by mutations of the NF1 gene and is one of the most common human autosomal dominant disorders. The patient shows different signs on the skin and other organs from early childhood. The best known are six or more café au lait spots, axillary or inguinal freckling, increased risk of developing benign nerve sheath tumours and plexiform neurofibromas. Mutation detection is complex, due to the large gene size, the large variety of mutations and the presence of pseudogenes. Using Ion Torrent PGM™ Platform, 73 mutations were identified in 79 NF1 Italian patients, 51% of which turned out to be novel mutations. Pathogenic status of each variant was classified using "American College of Medical Genetics and Genomics" guidelines criteria, thus enabling the classification of 96% of the variants identified as being pathogenic. The use of Next Generation Sequencing has proven to be effective as for costs, and time for analysis, and it allowed us to identify a patient with NF1 mosaicism. Furthermore, we designed a new approach aimed to quantify the mosaicism percentage using electropherogram of capillary electrophoresis performed on Sanger method.

Von recklinghausen disease: one patient - various problems

von Recklinghausen disease (vRD), more widely known as neurofibromatosis type 1, belongs to a group of genetic disorders and it is considered to be the most common genodermatosis. The disease has an autosomal dominant pattern of inheritance that involves mutations within the NF1 gene located on chromosome 17 in locus q11.2. The product of the NF1 gene is neurofibromin and the protein is well known to be a tumor suppressor factor. This counteracts possible overactivity of RAS (protein)/MAPK (mitogen-activated protein kinase) and RAS/PI3K/AKT/mTOR (phoshatydyloinositol-3-kinase/V-akt murine thy-moma viral oncogene homologue/mammalian target of rapamycin) signaling transduction pathways, preventing from uncontrolled cell proliferation and subsequent tumor formation. A loss of proper functioning of this protein leads to a development of vRD; however, a large variability in a phenotype of the disease and the onset of cutaneous findings, not necessarily in childhood, may provide a clinical diagnosis of the disease late in adulthood. We present a 52-year-old male in whom the diagnosis of vRD was proposed in the sixth decade of life, despite of multiple nodular lesions disseminated over the skin of the whole body and different neurological disturbances, not considered for a long time as manifestations of genodermatosis.