Whole-Body Positron Emission Tomography with 18F-Fluorodeoxyglucose/Magnetic Resonance Imaging as a Screening Tool for the Detection of Malignant Transformation in Individuals with Neurofibromatosis Type 1.

Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death in patients with neurofibromatosis type 1. They can result from premalignant neurofibromas, including neurofibromas with atypia and atypical neurofibromatous neoplasms of uncertain biologic potential. Some phenotypic characteristics have been described as associated with their development. The aim of this study was to outline our use of whole-body positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging in adults with neurofibromatosis type 1, especially in the screening of asymptomatic individuals with a higher risk of developing an MPNST, and to study its impact on neurofibroma classification (malignant vs premalignant) and MPNST staging over time. Individuals with neurofibromatosis type 1 who underwent a positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging between 2017 and 2021 were included, analyzing separately the screened population. Maximum standard uptake value and diffusion-weighted imaging were assessed. Biopsy/surgery confirmed the diagnosis. In all, 345 positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging were performed in 241 patients, including 149 asymptomatic (62%) but at-risk patients. Eight MPNSTs in 8 screened individuals (5%), 6 neurofibromas with atypia in 4 individuals (3%), and 29 atypical neurofibromatous neoplasms of uncertain biologic potential in 23 individuals (15%) were diagnosed. Over time, the proportion of grade 3 MPNST and the malignant/premalignant ratio in screened individuals significantly decreased (P = .03 and P < .001, respectively). This study emphasizes the diagnostic and screening performances of whole-body positron emission tomography with 18F-fluorodeoxyglucose/magnetic resonance imaging in adults with neurofibromatosis type 1.

A core outcome domain set to assess cutaneous neurofibromas related to neurofibromatosis type 1 in clinical trials.

BACKGROUND: Cutaneous neurofibromas (cNF) are considered one of the highest burdens of neurofibromatosis type 1 (NF1). To date, no medical treatment can cure cNF or prevent their development. In that context, there is an urgent need to prepare and standardize the methodology of future trials targeting cNF. OBJECTIVES: The objective was to develop a core outcome domain set suitable for all clinical trials targeting NF1-associated cNF. METHODS: The validated approach of this work consisted of a three-phase methodology: (i) generating the domains [systematic literature review (SLR) and qualitative studies]; (ii) agreeing (three-round international e-Delphi consensus process and working groups); and (iii) voting. RESULTS: (i) The SLR and the qualitative studies (three types of focus groups and a French e-survey with 234 participants) resulted in a preliminary list of 31 candidate items and their corresponding definitions. (ii) A total of 229 individuals from 29 countries participated in the first round of the e-Delphi process: 71 patients, relatives or representatives (31.0%), 130 healthcare professionals (HCPs, 56.8%) and 28 researchers, representatives of a drug regulatory authority, industry or pharmaceutical company representatives or journal editors (12.2%). The overall participation rate was 74%. After round 2, five candidate items were excluded. Between rounds 2 and 3, international workshops were held to better understand the disagreements among stakeholders. This phase led to the identification of 19 items as outcome subdomains. (iii) The items were fused to create four outcome domains ('clinical assessment', 'daily life impact', 'patient satisfaction' and 'perception of health') and prioritized. The seven items that did not reach consensus were marked for the research agenda. The final core outcome domain set reached 100% of the votes of the steering committee members. CONCLUSIONS: Although numerous outcomes can be explored in studies related to cNF in NF1, the present study offers four outcome domains that should be reported in all trial studies, agreed on by international patients, relatives and representatives of patients; HCPs; researchers, representatives of drug regulatory authorities or pharmaceutical companies and journal editors. The next step will include the development of a set of core outcome measurement instruments to further standardize how these outcomes should be assessed.

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.

In-Hospital Clinical Features, Morbidity, and Mortality of Patients with Neurofibromatosis 1 in France: A Nationwide, Population-Based Retrospective Cohort Study.

Neurofibromatosis 1 (NF1) is a multisystem disease that can affect nearly every organ system. The aim of our study was to describe the in-hospital population with NF1 in France. We conducted a nationwide retrospective cohort study using the French hospital administrative database. A total of 11,425 patients with NF1 (53.4% female, 19,080 person years) were identified from January 2013 to December 2019. A total of 23% had at least one diagnosis of a comorbidity or NF1-associated complication or disease, and it was highest in the age group of 10-15 years. A total of 2,601 (22.8%) had a diagnosis of cancer. There were 366 (3.2%) in-hospital deaths, and we observed a standardized mortality ratio of 4.14 (95% confidence interval = 3.71-4.56), with a higher standardized mortality ratio in women and in the age group of 10-15 years. The standardized incident ratio (SIR) of cancer was 10.3 (95% confidence interval = 9.6-11.1). We observed high SIR values for cancer in childhood, with a decrease toward that of the general population by age 70 years. We observed high SIRs for NF1-associated cancers: CNS SIR of 195.4 (95% confidence interval = 172.2-220.9) and small intestine SIR of 102.9 (95% confidence interval = 71.7-143.2). The study provides a better understanding of the prognosis in people living with NF1.

cNF-Skindex in Adults Living with Neurofibromatosis 1: Severity Strata in France and Validation in United States Adults.

Cutaneous neurofibromas (cNF) contribute to the impairment of QOL in individuals with neurofibromatosis 1. The cNF-Skindex, validated in a French population, specifically assesses the cNF-related QOL. In this study, we first defined severity strata using an anchoring approach on the basis of patient's burden. In total, 209 patients answered the anchor question and the cNF-Skindex. We tested the agreement among the three strata, generated by all potential couples of cut-off values of the cNF-Skindex and the three strata defined in the anchor question. The cut-off values 12 and 49 provided the highest Kappa value (κ = 0.685, 95% confidence interval = 0.604-0.765). Second, we validated the score and the strata in a United States population using the answers provided by 220 French and 148 United States adults. In the multivariable linear regression analysis, the country of origin was not a factor associated with the score (P = 0.297). The number of cNF along the different severity strata was similar between the French and the United States populations. In conclusion, stratification constitutes a powerful tool to better interpret the cNF-Skindex in daily practice and in clinical trials. This study validates its use in two populations that together constitute a large cohort of patients willing to participate in clinical research.

Factors associated with remission at 5-year follow-up in recent-onset axial spondyloarthritis: results from the DESIR cohort.

OBJECTIVE: The factors contributing to long-term remission in axial SpA (axSpA) are unclear. We aimed to characterize individuals with axSpA at the 5-year follow-up to identify baseline factors associated with remission. METHODS: We included all patients from the DESIR cohort (with recent-onset axSpA) with an available Ankylosing Spondylitis Disease Activity Score-CRP (ASDAS-CRP) at 5-year follow-up. Patients in remission (ASDAS-CRP < 1.3) were compared with those with active disease by demographic, clinical, biological and imaging characteristics. A logistic model stratified on TNF inhibitor (TNFi) exposure was used. RESULTS: Overall, 111/449 patients (25%) were in remission after 5 years. Among those never exposed to TNFi, 31% (77/247) were in remission compared with 17% (34/202) of those exposed to TNFi. Patients in remission after 5 years were more likely to be male, HLA-B27+, have a lower BMI, and a higher education level. Baseline factors associated with 5-year remission in patients never exposed to TNFi included lower BASDAI [adjusted odds ratio (ORa) 0.9, 95% CI: 0.8, 0.9) and history of peripheral arthritis (ORa 2.1, 95% CI: 1.2, 5.3). In those exposed to TNFi, remission was associated with higher education level (ORa 2.9, 95% CI: 1.6, 5.1), lower enthesitis index (ORa 0.8, 95% CI: 0.7, 0.9), lower BASDAI (ORa 0.9, 95% CI: 0.9, 0.9) and lower BMI (ORa 0.8, 95% CI: 0.7, 0.9). CONCLUSION: This study highlights the difficulty in achieving 5-year remission in those with recent-onset axSpA, especially for the more active cases, despite the use of TNFi. Socio-economic factors and BMI are implicated in the outcome at 5 years.

Severe Phenotype in Patients with Large Deletions of NF1.

Complete deletion of the NF1 gene is identified in 5-10% of patients with neurofibromatosis type 1 (NF1). Several studies have previously described particularly severe forms of the disease in NF1 patients with deletion of the NF1 locus, but comprehensive descriptions of large cohorts are still missing to fully characterize this contiguous gene syndrome. NF1-deleted patients were enrolled and phenotypically characterized with a standardized questionnaire between 2005 and 2020 from a large French NF1 cohort. Statistical analyses for main NF1-associated symptoms were performed versus an NF1 reference population. A deletion of the NF1 gene was detected in 4% (139/3479) of molecularly confirmed NF1 index cases. The median age of the group at clinical investigations was 21 years old. A comprehensive clinical assessment showed that 93% (116/126) of NF1-deleted patients fulfilled the NIH criteria for NF1. More than half had café-au-lait spots, skinfold freckling, Lisch nodules, neurofibromas, neurological abnormalities, and cognitive impairment or learning disabilities. Comparison with previously described "classic" NF1 cohorts showed a significantly higher proportion of symptomatic spinal neurofibromas, dysmorphism, learning disabilities, malignancies, and skeletal and cardiovascular abnormalities in the NF1-deleted group. We described the largest NF1-deleted cohort to date and clarified the more severe phenotype observed in these patients.

Lymphoproliferative malignancies in patients with neurofibromatosis 1.

Neurofibromatosis 1 (NF1) is an inherited, autosomal-dominant, tumor predisposition syndrome with a birth incidence as high as 1:2000. A patient with NF1 is four to five times more likely to develop a malignancy as compared to the general population. The number of epidemiologic studies on lymphoproliferative malignancies in patients with NF1 is limited. The aim of this study was to determine the incidence rate of lymphoproliferative malignancies (lymphoma and leukemia) in NF1 patients followed in our referral center for neurofibromatoses. We used the Informatics for Integrated Biology and the Bedside (i2b2) platform to extract information from the hospital's electronic health records. We performed a keyword search on clinical notes generated between Jan/01/2014 and May/11/2020 for patients aged 18 years or older. A total of 1507 patients with confirmed NF1 patients aged 18 years and above were identified (mean age 39.2 years; 57% women). The total number of person-years in follow-up was 57,736 (men, 24,327 years; women, 33,409 years). Mean length of follow-up was 38.3 years (median, 36 years). A total of 13 patients had a medical history of either lymphoma or leukemia, yielding an overall incidence rate of 22.5 per 100,000 (0.000225, 95% confidence interval (CI) 0.000223-0.000227). This incidence is similar to that of the general population in France (standardized incidence ratio 1.07, 95% CI 0.60-1.79). Four patients had a medical history leukemia and 9 patients had a medical history of lymphoma of which 7 had non-Hodgkin lymphoma, and 2 had Hodgkin lymphoma. Our results show that adults with NF1 do not have an increased tendency to develop lymphoproliferative malignancies, in contrast to the general increased risk of malignancy. While our results are consistent with the recent population-based study in Finland, they are in contrast with the larger population-based study in England whereby NF1 individuals were found to be 3 times more likely to develop both non-Hodgkin lymphoma and lymphocytic leukemia. Large-scale epidemiological studies based on nationwide data sets are thus needed to confirm our findings.

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 phenotype¼ (ARP) composed by 30 patients with at least 2 subcutaneous neurofibromas (SC-NF) and «classical phenotype¼ (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.

Neurofibromatosis I and multiple sclerosis.

Neurofibromatosis 1 (NF1) is one of the most common autosomal dominant genetic disorders with a birth incidence as high as 1:2000. It is caused by mutations in the NF1 gene on chromosome 17 which encodes neurofibromin, a regulator of neuronal differentiation. While NF1 individuals are predisposed to develop benign and malignant nervous system tumors, various non-tumoral neurological conditions including multiple sclerosis (MS) have also been reported to occur more frequently in NF1. The number of epidemiologic studies on MS in NF1 individuals is very limited. The aim of this study was to determine the estimated population proportion of MS in NF1 patients followed in our Referral Centre for Neurofibromatosis using the Informatics for Integrated Biology and the Bedside (i2b2) platform to extract information from the hospital's electronic health records. We found a total 1507 patients with confirmed NF1, aged 18 years (y) and above (mean age 39.2y, range 18-88y; 57% women). Five NF1 individuals were found to have MS, yielding an estimated population proportion of 3.3 per 1000 (0.0033, 95% Confidence Interval 0.0014-0.0077). The median age at diagnosis was 45 y (range 28-49 y). Three patients had relapsing-remitting MS and two patients had secondary progressive MS. Patients with NF1 were found to be twice more likely to develop MS than the general population in France (odds ratio 2.2), however this result was not statistically significant (95% Confidence Interval 0.91-5.29). Our results show that patients with NF1 might have a slight increased tendency to develop MS; however, due to the small sample size of our study, the results may not be sufficiently powered to detect this rare association. Large-scale epidemiological studies based on nationwide datasets are needed to confirm our findings. These findings further emphasize the need for a focused follow-up of patients with NF1, as early detection and management of MS can prevent further neurological disability.

Neurofibromatosis 1 French national guidelines based on an extensive literature review since 1966.

Neurofibromatosis type 1 is a relatively common genetic disease, with a prevalence ranging between 1/3000 and 1/6000 people worldwide. The disease affects multiple systems with cutaneous, neurologic, and orthopedic as major manifestations which lead to significant morbidity or mortality. Indeed, NF1 patients are at an increased risk of malignancy and have a life expectancy about 10-15 years shorter than the general population. The mainstay of management of NF1 is a patient-centered longitudinal care with age-specific monitoring of clinical manifestations, aiming at the early recognition and symptomatic treatment of complications as they occur. Protocole national de diagnostic et de soins (PNDS) are mandatory French clinical practice guidelines for rare diseases required by the French national plan for rare diseases. Their purpose is to provide health care professionals with guidance regarding the optimal diagnostic and therapeutic management of patients affected with a rare disease; and thus, harmonizing their management nationwide. PNDS are usually developed through a critical literature review and a multidisciplinary expert consensus. The purpose of this article is to present the French guidelines on NF1, making them even more available to the international medical community. We further dwelled on the emerging new evidence that might have therapeutic potential or a strong impact on NF1 management in the coming feature. Given the complexity of the disease, the management of children and adults with NF1 entails the full complement healthcare providers and communication among the various specialties.

Segmental schwannomatosis: characteristics in 12 patients.

BACKGROUND: Segmental schwannomatosis is characterized by multiple schwannomas affecting one-limb or less than 5 contiguous segments of spine. Its characteristics are not well described in the literature. Our objective was to better describe the demographic and clinical characteristics of this condition. METHODS: This was a retrospective, bi-center study conducted in two French expert centers for neurofibromatosis and schwannomatosis. The clinical, radiographic, pathological and molecular aspects were extracted from patients' clinical records. RESULTS: Twelve patients with segmental schwannomatosis were identified. Eight were female and 4 were male. The median age at initial symptom was 29 years (range: 6-60 years) and the median age at diagnosis was 34.5 years (range: 13-65 years). Pain was the initial symptom for the majority of patients (7 of 12). The number of tumors was variable with six patients having more than 10 tumors. Peripheral distribution was seen in all patients. Quality of life could be impaired (median Dermatology Life Quality Index score was 4.5 (range: 2-13). The median duration of follow up was 3 years (range: 1-26). Chronic pain was the main complication (9 of 12 patients). Surgical intervention to control chronic pain was performed for 9 patients of whom 5 experienced recurrence of tumors. Molecular investigations revealed heterozygous LZTR1 variants in 3 of 9 patients. CONCLUSION: Segmental schwannomatosis is a rare condition that may start early in life and often remains undiagnosed for many years. Pain is the main symptom and consequently could impair the quality of life. Surgery seems to be effective, but recurrences are frequent. Some patients carried heterozygous LZTR1 variants. Further studies are needed to better understand this rare condition.

Breast cancer risk in neurofibromatosis type 1 is a function of the type of NF1 gene mutation: a new genotype-phenotype correlation.

BACKGROUND: Neurofibromatosis type 1 (NF1) predisposes to breast cancer (BC), but no genotype-phenotype correlations have been described. METHODS: Constitutional NF1 mutations in 78 patients with NF1 with BC (NF1-BC) were compared with the NF1 Leiden Open Variation Database (n=3432). RESULTS: No cases were observed with whole or partial gene deletions (HR 0.10; 95% CI 0.006 to 1.63; p=0.014, Fisher's exact test). There were no gross relationships with mutation position. Forty-five (64.3%; HR 6.4-83) of the 70 different mutations were more frequent than expected (p<0.05), while 52 (74.3%; HR 5.3-83) were significant when adjusted for multiple comparisons (adjusted p≤0.125; Benjamini-Hochberg). Higher proportions of both nonsense and missense mutations were also observed (adjusted p=0.254; Benjamini-Hochberg). Ten of the 11 missense cases with known age of BC occurred at <50 years (p=0.041). Eighteen cases had BRCA1/2 testing, revealing one BRCA2 mutation. DISCUSSION: These data strongly support the hypothesis that certain constitutional mutation types, and indeed certain specific variants in NF1 confer different risks of BC. The lack of large deletions and excess of nonsenses and missenses is consistent with gain of function mutations conferring risk of BC, and also that neurofibromin may function as a dimer. The observation that somatic NF1 amplification can occur independently of ERBB2 amplification in sporadic BC supports this concept. A prospective clinical-molecular study of NF1-BC needs to be established to confirm and build on these findings, but regardless of NF1 mutation status patients with NF1-BC warrant testing of other BC-predisposing genes.

Can power Doppler ultrasound of the entheses help in classifying recent axial spondyloarthritis? Data from the DESIR cohort.

Early diagnosis of axial spondyloarthritis (axSpA) remains a challenge due to the lack of specificity of clinical symptoms and variable prevalence of axial imaging findings permitting a definite diagnosis. Power Doppler ultrasonography (PDUS) of the entheses has demonstrated to be a potential useful tool for the classification and diagnostic management of early SpA independently of the phenotype. OBJECTIVES: To assess the classification value (sensitivity and specificity) of PDUS-defined enthesitis for identifying patients fulfilling Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axSpA (ASAS+) in patients with recent inflammatory back pain (IBP) (the DESIR (DEvenir des Spondylarthropathies Indifférenciées Récentes) cohort). METHODS: Baseline PDUS was performed at eight entheseal sites, and PDUS enthesitis was defined by the presence of vascularisation at entheseal insertion. RESULTS: 402 patients from the DESIR cohort underwent a PDUS evaluation. PDUS enthesitis was detected in 58 (14.4%) patients of whom 40 (14.2%) belonged to the ASAS+ patients and 18 (17%) to the ASAS- patients. The sensitivity of PDUS enthesitis was 13.9% and the specificity was 83.5%, with a positive predictive value of 69% and 26.8% of negative predictive value for meeting ASAS criteria for axSpA. Of the 18 ASAS- patients with positive PDUS, 59% fulfilled Amor's criteria, 88% European Spondyloarthropathy Study Group criteria and 59% both. CONCLUSIONS: In a cohort of patients with recent IBP, the prevalence of PDUS enthesitis was low (14.4%); however, its specificity for classifying patients as axSpA according to ASAS criteria was high (83.5%). PDUS enthesitis might be of additional value for classifying as patients with axSpA IBP who do not fulfil ASAS criteria.

What is the reliability of non-trained investigators in recognising structural MRI lesions of sacroiliac joints in patients with recent inflammatory back pain? Results of the DESIR cohort.

OBJECTIVE: The objective of this study was to evaluate the reliability of recognising structural lesions on MRI (erosions, fatty lesions, ankylosis) of the sacroiliac joints (MRI-SIJ) in clinical practice compared to a central reading in patients with a possible recent axial spondyloarthritis (axSpA). METHODS: Patients aged 18-50 years, with recent (<3 years) and chronic (≥3 months) inflammatory back pain, suggestive of axSpA were included in the DEvenir des Spondyloarthrites Indifférenciées Récentes (DESIR) cohort. MRI-SIJ structural lesions were scored by non-trained local readers, and by two trained central readers. Local readers scored each SIJ as normal, doubtful or definite lesions. Central readers scored separately each type of lesion. The central reading (mean of the two central readers' scores) was the external standard. Agreement (κ) was calculated first between local (3 definitions of a positive MRI-SIJ) and central readings (9 definitions), and then between the two central readers. RESULTS: 664/708 patients with complete available images were included. Agreements between local and central readings were overall 'fair', except when considering at least 2 or 3 fatty lesions and at least 3 erosions and/or fatty lesions where agreement was 'moderate'. Agreement between central readers was similar. MRI-SIJ was positive for 52.6% of patients according to central reading (at least 1 structural lesion) and for 35.4% of patients according to local reading (at least unilateral 'doubtful' or 'definite' structural lesions). CONCLUSIONS: Agreement on a positive structural MRI-SIJ was fair to moderate between local and central readings, as well as between central readers. The reliability improved when fatty lesions were considered. TRIAL REGISTRATION NUMBER: NCTO 164 8907.

NF1 single and multi-exons copy number variations in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is caused by dominant loss-of-function mutations of the tumor suppressor NF1 containing 57 constitutive coding exons. A huge number of different pathogenic NF1 alterations has been reported. The aim of the present study was to evaluate the usefulness of a multiplex ligation-dependent probe amplification (MLPA) approach in NF1 patients to detect single and multi-exon NF1 gene copy number variations. A genotype-phenotype correlation was then performed in NF1 patients carrying these types of genetic alterations. Among 565 NF1 index cases from the French NF1 cohort, single and multi-exon deletions/duplications screening identified NF1 partial deletions/duplications in 22 patients (~4%) using MLPA analysis. Eight single exon deletions, 11 multiple exons deletions, 1 complex rearrangement and 2 duplications were identified. All results were confirmed using a custom array-CGH. MLPA and custom array-CGH allowed the identification of rearrangements that were missed by cDNA/DNA sequencing or microsatellite analysis. We then performed a targeted next-generation sequencing of NF1 that allowed confirmation of all 22 rearrangements. No clear genotype-phenotype correlations were found for the most clinically significant disease features of NF1 in patients with single and multi-exons NF1 gene copy number changes.