Neurofibromatosis type 1 and chronic neurological conditions in the United States: an administrative claims analysis

Diagnosis and management of neurofibromatosis type 1 in Arabian Gulf Cooperation Council Region: challenges and recommendations

Neurofibromatosis type 1 (NF1) is a complex multisystem genetic disorder that requires long-term, age-specific monitoring and multidisciplinary care. NF1 symptom burden can significantly affect the quality of life and impose a substantial economic burden on patients and their families. The approval and widespread availability of mitogen-activated protein kinase (MEK) inhibitors such as selumetinib for NF1-related plexiform neurofibromas have revolutionized the standard of care for patients with NF1, however their effective utilization hinges on early recognition of NF1. We present a consensus manuscript describing the challenges observed in the Arabian Gulf Cooperation Council (GCC) for diagnosing and managing NF1. Experts from the GCC also present recommendations for the early recognition and management of NF1 and its complications. A referral pathway that can play a crucial role in helping primary healthcare providers refer their patients to experts is also proposed. Increasing the availability and accessibility of genetic testing at an affordable cost and optimizing personalized NF1 care are essential for NF1 management. Developing regional guidelines for NF1 management and establishing NF1 centers of excellence may facilitate better care and outcomes for patients with NF1 in the GCC region.

Coexistence of neurofibromatosis type I, multiple sclerosis, and ischemic stroke: A case report and literature review

Neurofibromatosis type I and multiple sclerosis, when considered separately, are associated with a higher risk of cerebrovascular accident. The coexistence of neurofibromatosis type I and multiple sclerosis may lead to a further increase in cerebrovascular risk; however, this has not been reported in the literature. We report the case of a 37-year-old woman affected by both neurofibromatosis type I and multiple sclerosis: she was referred to our rehabilitation department because of a recent event of ischemic stroke. Moreover, we provide a comprehensive and updated review of all published cases reporting the coexistence of neurofibromatosis type I and multiple sclerosis to gather information regarding their association with cerebrovascular accidents.

The contribution of morbidity and unemployment for the reduced labor market participation of individuals with neurofibromatosis 1 in Finland

Neurofibromatosis 1 (NF1) is a multisystem disorder associated with, for example, a high risk for cancer, a variety of behavioral and cognitive deficits, low educational attainment and decreased income. We now examined the labor market participation of individuals with NF1. We analyzed the numbers of days of work, unemployment, and sickness allowance among 742 Finnish individuals with NF1 aged 20-59 years using nationwide register data from Statistics Finland and the Social Insurance Institution of Finland. The individuals with NF1 were compared with a control cohort of 8716 individuals matched with age, sex, and the area of residence. Individuals with NF1 had a significantly lower number of working days per year than the controls (rate ratio [RR] 0.93, 95% CI 0.91-0.95). Unemployment (RR 1.79, 95% CI 1.58-2.02), and sickness absence (RR 1.44, 95% CI 1.25-1.67) were more frequent in the NF1 than in the control group. The causes of sickness allowances were highly concordant with the previously reported morbidity profile of NF1 including neoplasms, cardiovascular disease, mental and behavioral diseases, and neurological diseases. In conclusion, NF1 significantly interferes with labor market participation via both unemployment and morbidity. Unemployment seems to cause more days of not working than sickness absence.

Persistent level 1 hypoglycemia due to hypothyroidism and underlying Neurofibromatosis type 1

Key Clinical Message

Hypoglycemia in non-diabetic patients is rare and may be due to various etiologies. It is important to recognize hypoglycemia early and appropriately manage hypoglycemia in patients with neurofibromatosis 1 and hypothyroidism.

Abstract

Non-diabetic hypoglycemia is not common and can be seen in certain conditions like Neurofibromatosis type 1 (NF1). We report a rare case of 66-year-old man with hypothyroidism and NF1 who developed a persistent level 1 hypoglycemia.

Cohort profile: life with neurofibromatosis 1 - the Danish NF1 cohort

PURPOSE

The Danish neurofibromatosis 1 (NF1) cohort was initiated to study health-related, socioeconomic and psychological consequences of living with the monogenetic disorder NF1 using a nationwide and population-based approach.

PARTICIPANTS

The cohort includes all 2467 individuals in Denmark who were hospitalised with or due to NF1 from 1977 to 2013 or registered in the RAREDIS Database (1995-2013), a national clinical database for rare diseases, or both. A comparison cohort matched to individuals with NF1 on sex and date of birth was identified in the Civil Registration System (n=20 132).

FINDINGS TO DATE

All cohort members were linked to the unique Danish registries to obtain information on hospital contacts, birth outcomes, education and partnership. A questionnaire was completed by 244 of the 629 adult cohort members with NF1 registered in the RAREDIS Database to evaluate the psychosocial and emotional burden. Further, neuropsychological tests were performed on 103 adult cohort members with NF1 and 38 adult population comparisons. To date, six studies have been published. Individuals with NF1 had an increased risk for (1) hospitalisation for disorders affecting all organ systems of the body throughout all decades of life, (2) psychiatric disorders, (3) attaining a short or medium long education and (4) not forming a life partner. Women with NF1 had an increased risk for spontaneous abortions and stillbirths. Finally, adults with NF1 had an impaired quality of life and a high need for professional support for physical, psychological and work-related problems, which was partly associated with disease severity and visibility.

FUTURE PLANS

The cohort will regularly be updated with newly diagnosed patients in the RAREDIS Database as well as with outcome information in the Danish registries. New studies are in progress to assess other medical and socioeconomic dimensions of living with NF1.

Improved renal function in neurofibromatosis type 1 patients

Neurofibromatosis type 1 (NF1), or von Recklinghausen disease, is an autosomal dominant disease that presents with various symptoms, including café‐au‐lait spots and neurofibromas. NF1 patients occasionally suffer from renal artery vasculopathy, which impairs renal function, while results of a previous report suggested that male NF1 patients have a low creatinine level in peripheral blood. The assessment of renal function in NF1 patients remains inadequate. In this study, renal function in NF1 was assessed. We recruited 308 patients consisting of 149 NF1 patients (77 males and 72 females) and 159 control patients (102 males and 57 females). Creatinine, blood urea nitrogen and haemoglobin A1c in peripheral blood as well as protein, occult blood and sugar in urine were examined. In addition, the estimated glomerular filtration rate was calculated. The mean age and body mass index did not differ significantly between the NF1 patients and controls for both sexes. For both sexes, i) the mean creatinine value was significantly lower in the NF1 patients than in the controls; ii) the mean blood urea nitrogen value did not differ significantly between the NF1 patients and controls; iii) the mean blood urea nitrogen‐to‐creatinine ratio was significantly higher in the NF1 patients than in the controls; iv) the mean estimated glomerular filtration rate was significantly higher in the NF1 patients than in the controls; and v) the mean haemoglobin A1c value was significantly lower in the NF1 patients than in the controls. In conclusion, NF1 patients may have improved renal function. The clinical significances should be further examined.

Is There a Tendency for Autoimmunity in Neurofibromatosis Type 1? -Case Reports

Autoimmune diseases have been reported in association with neurofibromatosis type 1 (NF1) in adults. Two children with NF1 and concurrent autoimmune diseases: antimuscle-specific kinase antibody-positive myasthenia and juvenile idiopathic arthritis are reported. The possible mechanisms of autoimmunity in NF1, particularly dysregulation in T lymphocyte proliferation and exposure to free DNA were discussed. In clinical practice, the possibility of a superposed disorder is to be considered, particularly on the background of a common clinical condition like NF1.

Primary Progressive Multiple Sclerosis in a Portuguese Patient With Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a frequent genetic neurocutaneous syndrome and multiple sclerosis (MS) is an acquired demyelinating disease of the central nervous system. The association of both these diseases is rare. In this case report, we describe a 25-year-old man with gait impairment, upper limbs tremor, slurred speech, and urinary symptoms in the form of urinary urgency and incontinence. These symptoms started a year earlier and had a progressive course. Examination revealed scattered café-au-lait spots, right ptosis, bilateral horizontal and vertical nystagmus, mild dysarthria, quadriparesis with generalized hyperreflexia and bilateral Babinski signs, upper limb tremor, bilateral proprioceptive errors, bilateral appendicular dysmetria, and severe gait ataxia. Brain MRI showed lesions involving the deep and subcortical white matter, as well as thalami, with no enhancement after administration of gadolinium, suggestive of focal areas of signal intensity (FASI) in the setting of NF1. There were also oval lesions in the periventricular white matter, perpendicular to the ventricles and involving the corpus callosum, which were atypical for FASI. Spinal MRI also demonstrated several lesions, which mildly enhance after administration of gadolinium. Cerebrospinal fluid (CSF) examination revealed mild lymphocytic pleocytosis (18/μL), mildly elevated protein (0.53 g/L), normal glucose, and positive oligoclonal IgG bands. Extensive laboratory workup, including microbiological CSF studies, aquaporin-4-IgG, myelin-oligodendrocyte glycoprotein-IgG, autoimmune screening, and viral serology, was negative. The genetic study revealed a new mutation in the NF1 gene that was not previously reported. We intend to discuss the genetic and autoimmune mechanisms by which MS and NF1 appear to be related and draw attention to this association because a timely diagnosis of MS is important to prevent further disability in NF1 patients.

Epilepsy in NF1: Epidemiologic, Genetic, and Clinical Features. A Monocentric Retrospective Study in a Cohort of 784 Patients

An increased lifetime risk of epilepsy has been reported in neurofibromatosis type 1 (NF1) patients, ranging between 4% and 14%. To further analyze the correlation between NF1 and epilepsy, we retrospectively reviewed the epidemiologic, clinical, radiological, and molecular data of 784 unselected patients diagnosed with NF1 and referred to the neurofibromatosis outpatient clinics at the University Hospital of Padua. A crude prevalence of epilepsy of 4.7% was observed. In about 70% of cases, seizures arose in the context of neuroradiological findings, with the main predisposing factors being cerebral vasculopathies and hydrocephalus. In the absence of structural abnormalities, the prevalence of epilepsy was found to be 1.27%, which is approximately equal to the total prevalence in the general population. NF1 patients with seizures exhibit a higher incidence of intellectual disability and/or developmental delay, as well as of isolated learning disabilities. The comparison of causative NF1 mutations between the two groups did not reveal a specific genotype-phenotype correlation. Our data refine the current knowledge on epileptological manifestations in NF1 patients, arguing against the hypothesis that specific mechanisms, inherent to neurofibromin cellular function, might determine an increased risk of epilepsy in this condition.

Nf1 heterozygous mice recapitulate the anthropometric and metabolic features of human neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a heritable cancer predisposition syndrome resulting from mutations in the NF1 tumor suppressor gene. Genotype-phenotype correlations for NF1 are rare due to the large number of NF1 mutations and role of modifier genes in manifestations of NF1; however, emerging reports suggest that persons with NF1 display a distinct anthropometric and metabolic phenotype featuring short stature, low body mass index, increased insulin sensitivity, and protection from diabetes. Nf1 heterozygous (Nf1+/-) mice accurately reflect the dominant inheritance of NF1 and are regularly employed as a model of NF1. Here, we sought to identify whether Nf1+/- mice recapitulate the anthropometric and metabolic features identified in persons with NF1. Littermate 16-20 week-old male wildtype (WT) and Nf1+/- C57B/6J mice underwent nuclear magnetic resonance (NMR), indirect calorimetry, and glucose/insulin/pyruvate tolerance testing. In some experiments, tissues were harvested for NMR and histologic characterization. Nf1+/- mice are leaner with significantly reduced visceral and subcutaneous fat mass, which corresponds with an increased density of small adipocytes and reduced leptin levels. Additionally, Nf1+/- mice are highly reliant on carbohydrates as an energy substrate and display increased glucose clearance and insulin sensitivity, but normal response to pyruvate suggesting enhanced glucose utilization and preserved gluconeogenesis. Finally, WT and Nf1+/- mice subjected to high glucose diet were protected from diet-induced obesity and hyperglycemia. Our data suggest that Nf1+/- mice closely recapitulate the anthropometric and metabolic phenotype identified in persons with NF1, which will impact the interpretation of previous and future translational studies of NF1.

Physical therapy to address fall risk in an individual with neurofibromatosis

Background: While physical therapy may help improve function and quality of life in patients with neurofibromatosis (NF), a standard of care remains to be established. This case report describes the physical therapy management of an individual with NF who was at high fall risk.Case Description: A 61-year-old male with NF and multiple comorbidities was determined to be at high fall risk by the Dynamic Gait Index, Berg Balance Scale, and Modified Falls Efficacy Scale. Deficits included coordination and strength which limited his ability to ascend and descend stairs or walk on uneven terrain. This reduced his independence at home and in his rural community. Interventions incorporated components of hip and trunk coordination, and addressed balance, strength, and functional mobility.Outcomes: The patient scored above the cutoff for high fall risk on all outcome assessments.Discussion: This case report describes physical therapy management to reduce fall risk for an individual with NF. Due to the limited research on NF, the treatment plan was developed using evidence-based practice for fall-risk reduction in other neurological disorders.

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.

Haploinsufficiency of the NF1 gene is associated with protection against diabetes

Background

The hereditary predisposition to diabetes is only partially explained by genes identified so far. Neurofibromatosis type 1 (NF1) is a rare monogenic dominant syndrome caused by aberrations of the NF1 gene. Here, we used a cohort of 1410 patients with NF1 to study the association of the NF1 gene with type 1 (T1D) and type 2 diabetes (T2D).

Methods

A total of 1410 patients were confirmed to fulfil the National Institutes of Health diagnostic criteria for NF1 by individually reviewing their medical records. The patients with NF1 were compared with 14 017 controls matched for age, sex and area of residence as well as 1881 non-NF1 siblings of the patients with NF1. Register-based information on purchases of antidiabetic medication and hospital encounters related to diabetes were retrieved. The Cox proportional hazards model was used to calculate the relative risk for diabetes in NF1.

Results

Patients with NF1 showed a lower rate of T2D when compared with a 10-fold control cohort (HR 0.27, 95% CI 0.17 to 0.43) or with their siblings without NF1 (HR 0.28, 95% CI 0.16 to 0.47). The estimates remained practically unchanged after adjusting the analyses for history of obesity and dyslipidaemias. The rate of T1D in NF1 was decreased although statistically non-significantly (HR 0.58, 95% CI 0.27 to 1.25).

Conclusion

Haploinsufficiency of the NF1 gene may protect against T2D and probably T1D. Since NF1 negatively regulates the Ras signalling pathway, the results suggest that the Ras pathway may be involved in the pathogenesis of diabetes.

Increased insulin sensitivity in individuals with neurofibromatosis type 1

Objects To compare insulin resistance (IR) and metabolic aspects of patients with neurofibromatosis type 1 (NF1) and individuals without the disease. Subjects and methods Forty patients with NF1 were matched by sex, age, and body mass index (BMI) to 40 controls from the community. Blood samples were collected for biochemical assessment. Homeostasis model assessment adiponectin (HOMA-AD), Homeostasis model assessment insulin resistance (HOMA-IR), and adiponectin/leptin ratio (ALR) were used to identify IR. Results The median HOMA-IR values were similar between the groups. However, the HOMA-AD value was significantly lower and the ALR significantly higher in the NF1 group. Fasting blood glucose (FBG), leptin, and visfatin levels of patients with NF1 were significantly lower, although adiponectin levels were significantly higher than those in the controls. Fasting insulin and blood glucose levels 2 hours after administration of 75 g of dextrose, glycated hemoglobin, and resistin showed no significant differences between groups. The HOMA-AD correlated with BMI, FBG, blood glucose levels 2 hours after administration of 75 g of dextrose, fasting insulin, glycated hemoglobin, adiponectin, leptin, visfatin, ALR, and HOMA-IR. The ALR correlated with BMI leptin, visfatin, and adiponectin. Conclusions Lower levels of FBG, leptin, visfatin, and HOMA-AD, and higher adiponectin levels and ALR may be related to increased insulin sensitivity and lower occurrence of type 2 diabetes mellitus in patients with NF1.

Neurofibromatosis type 1

Neurofibromatosis type 1 is a complex autosomal dominant disorder caused by germline mutations in the NF1 tumour suppressor gene. Nearly all individuals with neurofibromatosis type 1 develop pigmentary lesions (café-au-lait macules, skinfold freckling and Lisch nodules) and dermal neurofibromas. Some individuals develop skeletal abnormalities (scoliosis, tibial pseudarthrosis and orbital dysplasia), brain tumours (optic pathway gliomas and glioblastoma), peripheral nerve tumours (spinal neurofibromas, plexiform neurofibromas and malignant peripheral nerve sheath tumours), learning disabilities, attention deficits, and social and behavioural problems, which can negatively affect quality of life. With the identification of NF1 and the generation of accurate preclinical mouse strains that model some of these clinical features, therapies that target the underlying molecular and cellular pathophysiology for neurofibromatosis type 1 are becoming available. Although no single treatment exists, current clinical management strategies include early detection of disease phenotypes (risk assessment) and biologically targeted therapies. Similarly, new medical and behavioural interventions are emerging to improve the quality of life of patients. Although considerable progress has been made in understanding this condition, numerous challenges remain; a collaborative and interdisciplinary approach is required to manage individuals with neurofibromatosis type1 and to develop effective treatments.

Extensive Peculiar Cutaneous Form of Neurofibromatosis Type I as a New Mutation - a Case Report

Neurofibromatosis-1 (NF1) is one of the most common hereditary multisystemic disorders. The disease manifests a variety of characteristic features that include: hyperpigmentary abnormalities of the skin (café-au-lait macules, freckles in the axillae, and iris Lisch nodules) and growth of benign peripheral nerve sheath tumors (neurofibromas) in the skin. Associated extracutaneous clinical features include: skeletal abnormalities, neurological, cardiovascular, endocrine and other malformations. NF1 is caused by mutation in the neurofibromatosis-1 gene, which codes for the protein neurofibromin. The inheritance of NF1 follows an autosomal dominant trait, although about 50% of patients present with new („de novo“) mutations, and represent the first member of their family. No difference in the severity of the disease can be found in patients with familial mutations versus those with new mutations. We present a 78-year-old female patient with an extreme cutaneous form of neurofibromatosis who reported no affected family member. Apart from skin problems, she had no major health issues in childhood and adolescence, but in recent decades she had frequent headaches, occasional abdominal pain, and vision and hearing impairment. About 10 to 14 days before admission, she developed a severe cough, shortness of breath, and chest and abdominal pain. On examination, the patient of short stature (hight: 152 cm, weight: 49 kg) presented with thousands of soft nodules dispersed over the whole body, except on extensor sides of thighs and lower legs; the nodules varied in color from skin-colored, livid erythematous, to brown-grey; the nodules on the abdomen were moist, partly bleeding from the base, and accompanied by an unpleasant odor. Her feet were also densely covered by dark purple lumps, with dystrophic changes of the toe nails that were thickened, frayed, and yellowish. The skeletal abnormalities included: short stature, severe osteoporosis and osteosclerosis of the head bone structure; degenerative arthropathc-spondylotic changes of the thoracolumbar spine segment with signs of diffuse skeletal hyperostosis; pronounced degenerative changes of the lumbar spine. CT scans of the head, chest and abdomen showed the following abnormalities: flattening of the paraventricular gyri and reduction of brain parenchyma with hypodensity of the white matter in terms of cortical atrophy; periventricular bilateral small post-ischemic microvascular brain lesions of varying chronicity; in the parenchyma of the upper left lung lobe the apical presence of small areas of pleural effusion with consequent subatelectic region; distended stomach and a small inner wall herniation; hypotrophic right kidney; atherosclerotic lesions of the abdominal aorta; low grade infrarenal kinking of the abdominal aorta. Pathohistological analysis of biopsy specimen taken from the nodule corresponded with cutaneous neurofibroma. Consultative examinations of various specialists pointed to the existence of the following comorbidities: obstructive respiratory syndrome and right lobe pneumonia that were treated by antibiotics, aminophylline and dexamethasone infusions; psycho-organic syndrome without focal neurological deficit; Lisch nodules in each eye, and senile cataract. Considering the age and medical presentation of the patient, no other treatment was considered. In conclusion, this is a sporadic case of cutaneous neurofibromatosis 1 in a 78-year-old female patient who presented with extremely severe cutaneous neurofibromas, making this case at least rather peculiar.

Lower fasting blood glucose in neurofibromatosis type 1

Studies indicate a lower occurrence of diabetes mellitus (DM) in patients with neurofibromatosis type 1 (NF1). Fasting blood glucose (FBG) level is the main criterion used to diagnose DM and glucose intolerance. Therefore, this study compared FBG level between adults with NF1 and non-NF1 controls. We selected clinical records of 57 out of 701 individuals attending the Neurofibromatosis Outpatient Reference Center of the Clinics Hospital of the Federal University of Minas Gerais in Brazil. The selected patients with NF1 were matched to non-NF1 controls selected from the Brazilian Longitudinal Study of Adult Health according to sex, age (range, 35-74 years) and BMI at a ratio of 1:3. In both groups, individuals with DM were excluded. Median FBG level in the NF1 group (86 mg/dl (range, 56-127 mg/dl)) was lower than that in the non-NF1 control group (102 mg/dl (range, 85-146 mg/dl)) (P<0.001). Prevalence of FBG level ≥100 mg/dl in the NF1 group (16%) was lower than that in the non-NF1 control group (63%) (P<0.05). The chance of a high FBG level was 89% lower in the NF1 group (odds ratio, 0.112; 95% CI, 0.067-0.188) (P<0.05). In conclusion, adults with NF1 showed a lower FBG level and a lower prevalence of high FBG level compared with non-NF1 controls.