Increased Risk of Cerebrovascular Disease Among Patients With Neurofibromatosis Type 1: Population-Based Approach

Can Hemorrhagic Stroke Genetics Help Forensic Diagnosis in Pediatric Age (<5 Years Old)?

When stroke occurs in pediatric age, it might be mistakenly interpreted as non-accidental head injury (NAHI). In these situations, a multidisciplinary approach is fundamental, including a thorough personal and familial history, along with accurate physical examination and additional investigations. Especially when the clinical picture is uncertain, it is important to remember that certain genetic conditions can cause bleeding inside the brain, which may resemble NAHI. Pediatric strokes occurring around the time of birth can also be an initial sign of undiagnosed genetic disorders. Hence, it is crucial to conduct a thorough evaluation, including genetic testing, when there is a suspicion of NAHI but the symptoms are unclear. In these cases, a characteristic set of symptoms is often observed. This study aims to summarize some of the genetic causes of hemorrhagic stroke in the pediatric population, thus mimicking non-accidental head injury, considering elements that can be useful in characterizing pathologies. A systematic review of genetic disorders that may cause ICH in children was carried out according to the Preferred Reporting Item for Systematic Review (PRISMA) standards. We selected 10 articles regarding the main genetic diseases in stroke; we additionally selected 11 papers concerning patients with pediatric stroke and genetic diseases, or studies outlining the characteristics of stroke in these patients. The disorders we identified were Moyamoya disease (MMD), COL4A1, COL4A2 pathogenic variant, Ehlers-Danlos syndrome (E-D), neurofibromatosis type 1 (Nf1), sickle cell disease (SCD), cerebral cavernous malformations (CCM), hereditary hemorrhagic telangiectasia (HHT) and Marfan syndrome. In conclusion, this paper provides a comprehensive overview of the genetic disorders that could be tested in children when there is a suspicion of NAHI but an unclear picture.

Discovery of a polymorphic gene fusion via bottom-up chimeric RNA prediction

Gene fusions and their chimeric products are commonly linked with cancer. However, recent studies have found chimeric transcripts in non-cancer tissues and cell lines. Large-scale efforts to annotate structural variations have identified gene fusions capable of generating chimeric transcripts even in normal tissues. In this study, we present a bottom-up approach targeting population-specific chimeric RNAs, identifying 58 such instances in the GTEx cohort, including notable cases such as SUZ12P1-CRLF3, TFG-ADGRG7 and TRPM4-PPFIA3, which possess distinct patterns across different ancestry groups. We provide direct evidence for an additional 29 polymorphic chimeric RNAs with associated structural variants, revealing 13 novel rare structural variants. Additionally, we utilize the All of Us dataset and a large cohort of clinical samples to characterize the association of the SUZ12P1-CRLF3-causing variant with patient phenotypes. Our study showcases SUZ12P1-CRLF3 as a representative example, illustrating the identification of elusive structural variants by focusing on those producing population-specific fusion transcripts.

Epidemiology and Outcomes of Neurofibromatosis Type 1 (NF-1): Multicenter Tertiary Experience

Purpose

The aim of this manuscript was to assess the epidemiology and clinical features of Neurofibromatosis type 1 (NF-1) based on the newly published revised NF-1 diagnostic criteria and to evaluate complications of NF-1 including neurodevelopmental disorders.

Patients and methods

A retrospective cross-sectional observational study was conducted in the Ministry of National Guard Health Affairs (MNGHA) healthcare organization branches including four tertiary hospitals and 51 primary health care centers in different regions in Saudi Arabia. This study included all patients diagnosed with NF1 using the revised NIH diagnostic criteria published in 2021 that were registered at the electronic medical records (EMR) from 2015 to 2021.

Results

A total of 184 patients fulfilled the diagnostic criteria and were included in this study. The median age at diagnosis was 11 years (IQR: 4.00-20.25). The most encountered diagnostic criteria in this study were Café-au-lait macules (85.3%), and (42.9%) were found to have two or more neurofibromas with plexiform neurofibroma being the most common subtype (23.36%), approximately (36.4%) of the patient with optic pathway glioma. Nearby (26.6%) of the patients displayed different type of tumors. Iris Lisch nodules were presented in 36.4% of patients at a median age of 12 years (IQR: 9.0-21.8). Cardiovascular abnormality was encountered in 9.8% of the patients. Around 27.7% of the patients reported headache and 11.4% of the patient suffered from different type of epilepsy. Besides, 10.5% of the patients had intellectual disability, 33.8% suffered from communication disorders, and 4.9% patients had ADHD.

Conclusion

The results of this study will enable practitioners to adopt a more holistic approach and prioritize numerous attributes, which they can subsequently incorporate into their therapeutic methodologies. Furthermore, the identification of these attributes will facilitate an expeditious and accurate diagnosis. Hence, the implementation of intervention during its nascent phase may result in a more advantageous consequence.

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.

Cerebral Vasculopathy in Children with Neurofibromatosis Type 1

Cerebrovascular abnormalities are a severe and often underrecognized complication of childhood neurofibromatosis type 1 (NF1). There are no prospective studies of cerebral vasculopathy in NF1; thus, the estimated frequency of vasculopathy varies between studies. The data is difficult to interpret due to the retrospective data collection and variability in whether imaging is done based on screening/surveillance or due to acute neurologic symptoms. The prevalent NF1-associated cerebral vasculopathy is moyamoya syndrome (MMS). Vascular changes can present without symptoms or with acute TIA or stroke-like symptoms or a range of progressive neurologic deficits. Advanced imaging may enhance sensitivity of neuroimaging in children. Medical and/or surgical interventions may prevent short- and long-term complications. Challenges for establishment of a screening protocol for cerebral vasculopathy in children with NF1 include the relatively large number of patients with NF1, the potential need for sedation to achieve quality imaging and the broad age range at time of detection for cerebral vascular changes. The goal of this review is to present the epidemiology, clinical presentation, imaging features and medical/surgical management of cerebral arteriopathies in children with NF1.

Neurofibromatosis type 1, fibromuscular dysplasia, and ischemic stroke: an association lost in time? A case report

Neurofibromatosis Type 1 (NF1) is a rare cause of ischemic stroke (IS) in the general population. We report a case of a young patient with NF1 in whom IS was caused by fibromuscular dysplasia. An angiographic study demonstrated occlusion in the right internal carotid artery (ICA), just after its origin, and the left ICA, just before the intracranial portion, and brain magnetic resonance imaging showed the limits of an area of brain infarction in the right frontoparietal region. Despite these concomitant neuroimaging findings, this association is rare, and it is difficult to establish the contribution to the outcome made by each of these diseases, which treatment is the best to implement, or what prognosis is.

A Rare Report of the Coexistence of Sickle Cell Disease, Neurofibromatosis Type 1, and Intracranial Hypertension in a Pediatric Patient

A pediatric female with sickle cell disease (SCD) and neurofibromatosis type 1 was noted to have incidental papilledema, with subsequent workup showing an elevated opening pressure. She was diagnosed with intracranial hypertension and began treatment with acetazolamide. Hydroxyurea was also discontinued. Acetazolamide was tapered off, and hydroxyurea was restarted with no worsening in her ophthalmologic exam. We report this case due to the rare occurrence of all 3 conditions, and while intracranial hypertension has been reported in SCD, the diagnostic workup for papilledema in hemoglobinopathies is not well defined. This case helps delineate the presentation and diagnostic workup of papilledema in SCD.

Imaging of Suspected Stroke in Children, From the AJR Special Series on Emergency Radiology

Pediatric stroke encompasses different causes, clinical presentations, and associated conditions across ages. Although it is relatively uncommon, pediatric stroke presents with poor short- and long-term outcomes in many cases. Because of a wide range of overlapping presenting symptoms between pediatric stroke and other more common conditions, such as migraine and seizures, stroke diagnosis can be challenging or delayed in children. When combined with a comprehensive medical history and physical examination, neuroimaging plays a crucial role in diagnosing stroke and differentiating stroke mimics. This review highlights the current neuroimaging workup for diagnosing pediatric stroke in the emergency department, describes advantages and disadvantages of different imaging modalities, highlights disorders that predispose children to infarct or hemorrhage, and presents an overview of stroke mimics. Key differences in the initial approach to suspected stroke between children and adults are also discussed.

Discovery of A Polymorphic Gene Fusion via Bottom-Up Chimeric RNA Prediction

Gene fusions and their chimeric products are typically considered hallmarks of cancer. However, recent studies have found chimeric transcripts in non-cancer tissues and cell lines. In addition, efforts to annotate structural variation at large scale have found examples of gene fusions with potential to produce chimeric transcripts in normal tissues. In this report, we provide a means for targeting population-specific chimeric RNAs to enrich for those generated by gene fusion events. We identify 57 such chimeric RNAs from the GTEx cohort, including SUZ12P1-CRLF3 and TFG-ADGRG7 , whose distribution we assessed across the populations of the 1000 Genomes Project. We reveal that SUZ12P1-CRLF3 results from a common complex structural variant in populations with African heritage, and identify its likely mechanism for formation. Additionally, we utilize a large cohort of clinical samples to characterize the SUZ12P1-CRLF3 chimeric RNA, and find an association between the variant and indications of Neurofibramatosis Type I. We present this gene fusion as a case study for identifying hard-to-find and potentially functional structural variants by selecting for those which produce population-specific fusion transcripts.

KEY POINTS

- Discovery of 57 polymorphic chimeric RNAs- Characterization of SUZ12P1-CRLF3 polymorphic chimeric RNA and corresponding rearrangement- Novel bottom-up approach to identify structural variants which produce transcribed gene fusions.

Cerebral Arteriopathies of Childhood - Current Approaches

Up to more than half of previously healthy children presenting with their first arterial ischemic stroke have a cerebral arteriopathy. Cerebral arteriopathies during childhood can be congenital, reflecting abnormal vessel development, or acquired when caused by disruption of vascular homeostasis. Distinguishing different types of cerebral arteriopathies in children can be challenging but of great clinical value as they may dictate different disease and treatment courses, and clinical and radiologic outcomes. Furthermore, children with stroke due to a specific arteriopathy exhibit distinctive features when compared to those with stroke due to other causes or a different type of arteriopathy. These features become crucial in the management of pediatric stroke by choosing appropriate diagnostic and treatment strategies. The objective of this article is to provide the reader with a comprehensive up-to-date review of the classification, symptoms, diagnosis, treatment, and outcome of cerebral arteriopathies in children.

Neurovascular complications in adults with Neurofibromatosis type 1: A national referral center experience

Neurofibromatosis type 1 (NF1) is associated with a range of vascular abnormalities. To assess the frequency, clinical and imaging spectrum of vascular complications in an adult cohort of NF1 patients, we reviewed 2068 adult NF1 patient records seen in our service between 2009 and 2019, to determine presence of vascular abnormalities, age at detection, associated symptoms and management. A literature review of the range of vascular abnormalities associated with NF1 was also undertaken. 1234 patients had magnetic resonance imaging cranial imaging. The frequency of vascular abnormalities associated with NF1 patients who had cranial imaging in this cohort was 3.5% (n = 43), the majority (n = 26, 60%) were symptomatic. Stroke and cerebral arterial stenosis were the commonest vascular complication. Eight patients (0.65%) had more than one type of vascular abnormality. One death due to a vascular complication was identified and significant morbidity resulted from other complications. We conclude that clinicians caring for patients with NF1 need to be cognizant that rapid onset of new neurological symptoms or signs may be the result of a vascular complication of NF1 and require urgent investigation and management, ideally within specialist teams who have experience of managing vascular complications of NF1.

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.

Ischemic stroke with extensive vasculopathy in a patient with neurofibromatosis type 1

Neurofibromatosis type 1 is an autosomal dominant genetic disorder with multisystem manifestations including vascular abnormalities. The condition is also associated with an increased risk of both ischemic and hemorrhagic stroke. Here we report a case of a 60-year-old male with known neurofibromatosis who presented with right sided hemiparesis. Neuroimaging work-up revealed left internal carotid artery dissection and tandem occlusion of the left internal carotid artery and left middle cerebral artery. There was associated territorial ischemic infarction. The patient was found to have extensive intra and extra cranial vasculopathy including gross basilar dolichoectasia and a right-sided cervical internal carotid artery pseudoaneurysm. This case highlights the clinical significance of neurofibromatosis associated vasculopathy which can result in stroke.

Association of Placenta Previa With Severe Maternal Morbidity Among Patients With Placenta Accreta Spectrum Disorder

IMPORTANCE

Placenta previa is widely acknowledged as a risk factor for placenta accreta spectrum (PAS) disorders, which are severe maternal complications; however, data are limited regarding whether placenta previa is associated with a higher risk of worse maternal outcomes among patients with PAS disorders.

OBJECTIVE

To examine the association between placenta previa and the risk of severe maternal morbidities (SMMs) and higher resource use among patients with PAS disorders.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study extracted records of 3793 patients with PAS diagnosis and delivery indicators between October 1, 2015, and December 31, 2019, from the US National Inpatient Sample database.

EXPOSURES

Placenta previa.

MAIN OUTCOMES AND MEASURES

Data on 21 Centers for Disease Control and Prevention-defined SMMs and 25 study-defined surgical morbidities associated with PAS were extracted. Six surgical procedures (cystoscopy, intra-arterial balloon occlusion, cesarean delivery, hysterectomy, cystectomy, and oophorectomy), hospital length of stay, and inpatient costs were compared. Multivariable Poisson regression models built in the generalized estimating equation framework were used.

RESULTS

Among 3793 patients with PAS (median [IQR] age at admission, 33 [29-37] years), 621 women (16.4%) were Black, 765 (20.2%) were Hispanic, 1779 (46.9%) were White, 441 (11.6%) were of other races and/or ethnicities (47 [1.2%] were American Indian, 220 [5.8%] were Asian or Pacific Islander, and 174 [4.6%] were of multiple or other races and/or ethnicities), and 187 (4.9%) were of unknown race and ethnicity. A total of 1323 patients (34.9%) had placenta previa and 2470 patients (65.1%) did not; of those with placenta previa, 405 patients (30.6%) had invasive PAS. Patients with vs without placenta previa had a significantly higher rate and risk of any SMM (935 women [70.7%] vs 1087 women [44.0%]; P < .001; adjusted risk ratio [aRR], 1.19; 95% CI, 1.12-1.27) and any surgical morbidity (1170 women [88.4%] vs 1667 women [67.5%]; P < .001; aRR, 1.18; 95% CI, 1.13-1.23). With regard to specific outcomes, those with vs without placenta previa had a significantly higher rate of peripartum hemorrhage (878 patients [66.4%] vs 1217 patients [49.3%]; P < .001), blood product transfusion (413 patients [31.2%] vs 610 patients [24.7%]; P < .001), shock (83 patients [6.3%] vs 108 patients [4.4%]; P = .01), disseminated intravascular coagulation or other coagulopathy (77 patients [5.8%] vs 105 patients [4.3%]; P = .04), and urinary tract injury (44 patients [3.3%] vs 41 patients [1.7%]; P = .002). Patients with vs without placenta previa were more likely to undergo cesarean delivery (1292 patients [97.7%] vs 1787 patients [72.3%]; P < .001), hysterectomy (786 patients [59.4%] vs 689 patients [27.9%]; P < .001), cystoscopy (301 patients [22.8%] vs 203 patients [8.2%]; P < .001), cystectomy (157 patients [11.9%] vs 98 patients [4.0%]; P < .001), and intra-arterial balloon occlusion (121 patients [9.1%] vs 77 patients [3.1%]; P < .001) and to have significantly longer hospital length of stay (median [IQR], 5 [4-11] days vs 3 [3-5] days; P < .001) and total inpatient costs (median [IQR], $17 496 [$10 863-$30 619] vs $9728 [$6130-$16 790]; P < .001). Hypertensive disorder of pregnancy was associated with a decreased risk of placenta previa (aRR, 0.67; 95% CI, 0.46-0.96) among patients with PAS.

CONCLUSIONS AND RELEVANCE

In this study, placenta previa was associated with an increased risk of maternal and surgical morbidities and higher resource use among women with PAS. These findings suggest that interventions to alleviate maternal and surgical morbidities are especially needed for patients with placenta previa-complicated PAS disorders.

Old and new perspectives on Neurofibromatosis type 1: Clinical and molecular characterization of 832 patients from a single centre over 16 years

Neurofibromatosis type 1 (NF1; OMIM #162200) is the commonest multi-systemic neurocutaneous tumour-predisposition disorder. It has an age-related complete penetrance but a highly variable inter- and intra-familial expressivity. This article summarizes the clinical features and molecular characteristics of 832 clinically or molecularly confirmed NF1 patients from 697 unrelated families recruited from a single centre in Hong Kong diagnosed during the 16 years period from Jan 2005 to Jan 2021. In this study, we have estimated the incidences of clinical features, reported on the molecular findings and explored new genotype-phenotype correlations.

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

RETINAL VASCULAR ABNORMALITIES IN CHILDREN WITH NEUROFIBROMATOSIS TYPE 1

PURPOSE

Retinal vascular abnormalities (RVAs) have been recently described in patients with neurofibromatosis Type 1 (NF1) as vascular tortuosity, best visible on infrared imaging. This study assessed clinical RVA's characteristics in a large series of children with NF1.

METHODS

This retrospective observational study was conducted in children (0-18 years) with an NF1 diagnosis. Using near-infrared imaging, RVAs were classified according to the nature of vessels involvement and their degree of tortuosity.

RESULTS

Retinal imaging from 140 children, with a median age of 8.8 years (1.5-18), was included; 52 patients (37.1%) (81 eyes) exhibited RVAs. These RVAs comprised 96% (50/52) of simple vascular tortuosity and 17% (9/52) of a corkscrew pattern. A corkscrew pattern involved only small veins, whereas simple vascular tortuosity could affect both arteries and veins. No statistically significant age correlation was observed, but evolution of RVAs from simple vascular tortuosity to corkscrew pattern was observed in 5 cases.

CONCLUSION

Retinal vascular abnormalities occurred in 37.1% of children with NF1. These abnormalities may result from NF1 promoting localized tortuosity in both small arteries and veins, whereas only small second-order or tertiary-order venules evolve to a highly tortuous pattern.

What Every Internist-Endocrinologist Should Know about Rare Genetic Syndromes in Order to Prevent Needless Diagnostics, Missed Diagnoses and Medical Complications: Five Years of 'Internal Medicine for Rare Genetic Syndromes'

Patients with complex rare genetic syndromes (CRGS) have combined medical problems affecting multiple organ systems. Pediatric multidisciplinary (MD) care has improved life expectancy, however, transfer to internal medicine is hindered by the lack of adequate MD care for adults. We have launched an MD outpatient clinic providing syndrome-specific care for adults with CRGS, which, to our knowledge, is the first one worldwide in the field of internal medicine. Between 2015 and 2020, we have treated 720 adults with over 60 syndromes. Eighty-nine percent of the syndromes were associated with endocrine problems. We describe case series of missed diagnoses and patients who had undergone extensive diagnostic testing for symptoms that could actually be explained by their syndrome. Based on our experiences and review of the literature, we provide an algorithm for the clinical approach of health problems in CRGS adults. We conclude that missed diagnoses and needless invasive tests seem common in CRGS adults. Due to the increased life expectancy, an increasing number of patients with CRGS will transfer to adult endocrinology. Internist-endocrinologists (in training) should be aware of their special needs and medical pitfalls of CRGS will help prevent the burden of unnecessary diagnostics and under- and overtreatment.

Neurofibromatosis type 1 with subarachnoid hemorrhage due to multiple and de novo aneurysms: a case report

Background

Neurofibromatosis type 1 causes various lesions in many organs including the skin, and the incidence of complications with intracranial aneurysms is 9–11%. Here we report a case of neurofibromatosis type 1 with subarachnoid hemorrhage due to multiple and de novo aneurysms.

Case presentation

The patient was a 49-year-old Japanese woman with a history of neurofibromatosis type 1. She was transported to our hospital owing to disturbance of consciousness and was diagnosed with subarachnoid hemorrhage by computed tomography. Computed tomography angiography revealed multiple, small intracranial aneurysms, and we suspected that one of them in the peripheral branch of the left middle cerebral artery was the source of hemorrhage based on the distribution of hematoma. The patient underwent emergency surgery. Because it was difficult to identify an aneurysm in the most peripheral part of the left middle cerebral artery in the initial surgery, only one aneurysm was clipped. Later, a peripheral aneurysm was clipped using the navigation system. Because both aneurysms were small intracranial aneurysms (< 2 mm), either of them could be the source of hemorrhage. The postoperative course was good, and the patient was discharged in healthy condition. Because brain magnetic resonance imaging performed in the previous year did not find aneurysms at the same site, she was diagnosed with rupture of a de novo aneurysm. Neurofibromatosis type 1 might have caused the rupture of multiple intracranial aneurysms in a short period in this patient.

Conclusion

Neurofibromatosis type 1 may be complicated by the formation of multiple intracranial aneurysms in a short period.

Hypertension and childhood stroke

Cerebrovascular disease (stroke) is one of the ten leading causes of death in children and adolescents. Multiple etiologies, from arteriopathies to prothrombic states, can cause stroke in youth. In adult stroke, hypertension has been shown to be the single most important modifiable risk factor. Although hypertension has not been strongly identified as a risk factor in childhood stroke to date, there is preliminary evidence that suggests that hypertension may also be associated with stroke in children. In this review, we summarize the literature that may link hypertension to stroke in the young. We have identified a series of barriers and limitations in the fields of pediatric hypertension and pediatric neurology that might explain why hypertension has been overlooked in childhood stroke. We suggest that hypertension may be a relevant risk factor that, alone or in combination with other multiple factors, contributes to the development of stroke in children. Currently, there are no consensus guidelines for the management of post-stroke hypertension in children. Thus, we recommend that blood pressure be assessed carefully in every child presenting with acute stroke in order to better understand the effects of hypertension in the development and the outcome of childhood stroke. We suggest a treatment algorithm to help practitioners manage hypertension after a stroke.

Association between neurofibromatosis type 1 and cerebrovascular diseases in children: A systematic review

BACKGROUND

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disease that affects one in every 3000 individuals. This disease can present a wide range of clinical manifestations, ranging from skin abnormalities to severe vascular damage. Although not commonly recognized in the context of NF-1, cerebrovascular disease (CVD), can be often present since childhood and diagnosed just later in life. When present, NF-1-associated CVD clinical manifestations may include headache, cognitive deficits and ultimately aneurysm rupture, causing death. Thus, CVD plays an important role in the clinical manifestations, disease severity and prognosis of patients with NF-1. This systematic review aims to summarize the body of evidence linking NF-1 and CVD in children.

METHODS

Two independent investigators performed a systematic review on the PubMed and EMBASE search platforms, using the following key terms: "neurofibromatosis type 1", "Von Recklinghausen's disease", "children", "adolescents", "stroke", "Moyamoya disease", "vascular diseases", "cerebrovascular disorders", "aneurysm" and "congenital abnormalities". Studies focused on assessing the development of CVD in children with NF-1 were included.

RESULTS

Seven studies met the inclusion criteria. Twelve different clinical manifestations have been associated with cerebrovascular changes in children with NF-1; 44,5% of diagnosed patients were asymptomatic.

CONCLUSION

The available evidence suggests that CVDs are related with the progression of NF-1, even in the absence of a clear clinical manifestation. In addition, improved prognosis was observed when imaging tests were performed to screen for cerebrovascular alterations early during the clinical investigation. Early diagnosis of CVD in NF-1 patients foster implementation of timely interventions, directly impacting clinical outcomes.

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.

Genetic basis of neurofibromatosis type 1 and related conditions, including mosaicism

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a frequent autosomal dominant disorder characterised by café-au-lait maculae (CALM), skinfold freckling, iris Lisch nodules and benign peripheral nerve sheath tumours (neurofibromas).

MECHANISM

The NF1 gene is a tumour suppressor gene and NF1 individuals have an increased risk for a long list of tumours, all resulting from a second hit in the normal copy of the NF1 gene. Remarkably, some non-tumour phenotypes such as CALM and pseudarthrosis are also caused by a "second hit". Germline mutations inactivating the NF1 gene show a large variability in genetic mechanisms ranging from single-nucleotide substitutions and somatic mosaicism to large deletions affecting neighbouring genes. Molecular confirmation of the clinical diagnosis is becoming increasingly more important to differentiate NF1 from other syndromes such as Legius syndrome, to investigate genotype-phenotype correlations relevant in 10% of cases and to detect somatic mosaicism.

SURVEILLANCE AND THERAPY

Some degree of learning difficulties, attention deficit and social problems are observed in most children and affect quality of life. There is a large individual variability in complications and the evolution of the disease is difficult to predict. Specialised outpatient clinics for children have been widely established and are important for surveillance and guidance. Regular surveillance is also important for adolescents and adults because many tumour complications can be detected by whole-body MRI and treated even before symptoms develop and irreversible damage occurs. Recent data on nodular plexiform neurofibromas with continued growth in adolescents and young adults show that many of these tumours are premalignant lesions called atypical neurofibromatous neoplasm of uncertain biological potential (ANNUBP). Specific surveillance and timely local resection of these benign peripheral nerve sheath tumours might be important to prevent malignant degeneration. In the last years, targeted therapy with MEK inhibitors has shown promise to treat unresectable and symptomatic plexiform neurofibromas. Many more challenges remain to find the best way to monitor children and adults for potential complications and to find a satisfying cure for many complications in this disorder.

Neurological manifestations of neurofibromatosis: a review

Neurofibromatosis type 1(NF1) is a dominantly inherited genetic disorder caused by a mutation in the NF1 tumor-suppressor gene. Patients are prone to develop benign and malignant tumors not only in the central and peripheral nervous system but also in other parts of the body. Apart from tumors, neurofibromatosis may also be associated with neurological symptoms and disorders such as cerebrovascular disease, epilepsy, neuropathy, and headache. This article seeks to review the different neurological manifestations of neurofibromatosis.

An update on the central nervous system manifestations of neurofibromatosis type 1

Neurofibromatosis 1 (NF1) is an autosomal dominant genetic disorder that presents with variable phenotypes as a result of mutations in the neurofibromatosis type 1 (NF1) gene and subsequently, abnormal function of the protein product, neurofibromin. Patients with NF1 are at increased risk for central nervous system (CNS) manifestations including structural, functional, and neoplastic disease. The mechanisms underlying the varied manifestations of NF1 are incompletely understood, but the loss of functional neurofibromin, resulting in sustained activation of the oncoprotein RAS, is responsible for tumorigenesis throughout the body, including the CNS. Much of our understanding of NF1-related CNS manifestations is from a combination of data from animal models and natural history studies of people with NF1 and CNS disease. Data from animal models suggest the importance of both Nf1 mutations and somatic genetic alterations, such as Tp53 loss, for development of neoplasms, as well as the role of the timing of the acquisition of such alterations on the variability of CNS manifestations. A variety of non-neoplastic structural (macrocephaly, hydrocephalus, aqueductal stenosis, and vasculopathy) and functional (epilepsy, impaired cognition, attention deficits, and autism spectrum disorder) abnormalities occur with variable frequency in individuals with NF1. In addition, there is increasing evidence that similar appearing CNS neoplasms in people with and without the NF1 syndrome are due to distinct oncogenic pathways. Gliomas in people with NF1 show alterations in the RAS/MAPK pathway, generally in the absence of BRAF alterations (common to sporadic pilocytic astrocytomas) or IDH or histone H3 mutations (common to diffuse gliomas subsets). A subset of low-grade astrocytomas in these patients remain difficult to classify using standard criteria, and occasionally demonstrate morphologic features resembling subependymal giant cell astrocytomas that afflict patients with tuberous sclerosis complex ("SEGA-like astrocytomas"). There is also emerging evidence that NF1-associated high-grade astrocytomas have frequent co-existing alterations such as ATRX mutations and an alternative lengthening of telomeres (ALT) phenotype responsible for unique biologic properties. Ongoing efforts are seeking to improve diagnostic accuracy for CNS neoplasms in the setting of NF1 versus sporadic tumors. In addition, MEK inhibitors, which act on the RAS/MAPK pathway, continue to be studied as rational targets for the treatment of NF1-associated tumors, including CNS tumors.

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.

Early-onset stroke in two siblings with Neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder, characterized by cafe-au-lait macules, benign neurofibromas as well as malignant peripheral nerve sheath tumours, freckling in the axillary or inguinal regions, optic glioma and Lisch nodules (iris hamartomas) and further manifestations like bone deformities etc. Additionally, NF1 patients are at increased risk of early-onset cerebrovascular diseases, the pathogenesis of which has not been clarified yet. Here we report the first case of two siblings with NF1 who suffered an acute ischemic stroke. Professionals treating NF1 patients should be aware of the elevated risk of stroke in this population. Large prospective studies are needed to establish optimal guidelines for diagnosis, monitoring and treatment of cerebrovascular disease in patients suffering from NF1, as well as to achieve a consensus on routine vascular screening in NF1.

Caring for children with neurofibromatosis type 1

This article discusses the variable physical manifestations of neurofibromatosis type 1 among children in terms of presentation, disease severity, and prognosis, and addresses appropriate nursing interventions and patient teaching.

Monogenic, Polygenic, and MicroRNA Markers for Ischemic Stroke

Ischemic stroke (IS) is a leading disease with high mortality and disability, as well as with limited therapeutic window. Biomarkers for earlier diagnosis of IS have long been pursued. Family and twin studies confirm that genetic variations play an important role in IS pathogenesis. Besides DNA mutations found previously by genetic linkage analysis for monogenic IS (Mendelian inheritance), recent studies using genome-wide associated study (GWAS) and microRNA expression profiling have resulted in a large number of DNA and microRNA biomarkers in polygenic IS (sporadic IS), especially in different IS subtypes and imaging phenotypes. The present review summarizes genetic markers discovered by clinical studies and discusses their pathogenic molecular mechanisms involved in developmental or regenerative anomalies of blood vessel walls, neuronal apoptosis, excitotoxic death, inflammation, neurogenesis, and angiogenesis. The possible impact of environment on genetics is addressed as well. We also include a perspective on further studies and clinical application of these IS biomarkers.

Long-term health and social function in adult survivors of paediatric astrocytoma: A report from the Childhood Cancer Survivor Study

BACKGROUND

Although paediatric astrocytoma has an excellent 5-year survival rate, survivors remain at risk for morbidity and late mortality. This study aimed to estimate the risk of late mortality, chronic conditions, poor health status and social impairment in ageing paediatric astrocytoma survivors.

METHODS

We longitudinally evaluated 1182 5-year astrocytoma survivors diagnosed between 1970 and 1986 and 4023 siblings enrolled in a retrospective cohort study. Kaplan-Meier estimates of late mortality and cumulative incidence of serious chronic conditions were estimated. Cox regression models provided hazard ratios (HRs) with 95% confidence intervals (CIs) for development of chronic conditions, and generalised linear models provided relative risks (RRs) of the poor health status and social outcomes.

RESULTS

At 30 years from diagnosis, cumulative late mortality was 22.1% (CI 20.0-24.3%), primarily due to disease progression or recurrence. Compared with siblings, survivors were at increased risk of serious chronic conditions (HR 4.6, CI 3.8-5.5). Survivors reported higher rates of poor general health (RR 3.3, CI 2.8-3.8), poor mental health (RR 1.9, CI 1.7-2.1), functional impairment (RR 9.0, CI 7.7-10.5) and activity limitation (RR 3.6, CI 3.1-4.2) and lower rates of college graduation (RR 0.75, CI 0.69-0.82), marriage (RR 0.62, CI 0.58-0.66), employment (RR 0.75, CI 0.72-0.79) and household income ≥$40,000 (RR 0.68, CI 0.64-0.73). Even survivors without radiation exposure had elevated risk of chronic conditions, poor health status and social impairment compared with siblings.

CONCLUSIONS

Survivors of paediatric astrocytoma are at high risk for long-term complications of their disease and its treatment. They require lifelong monitoring for late effects.

Neurocutaneous Disorders

PURPOSE OF REVIEW

This article presents an up-to-date summary of the genetic etiology, diagnostic criteria, clinical features, and current management recommendations for the most common neurocutaneous disorders encountered in clinical adult and pediatric neurology practices.

RECENT FINDINGS

The phakomatoses are a phenotypically and genetically diverse group of multisystem disorders that primarily affect the skin and central nervous system. A greater understanding of the genetic and biological underpinnings of numerous neurocutaneous disorders has led to better clinical characterization, more refined diagnostic criteria, and improved treatments in neurofibromatosis type 1, Legius syndrome, neurofibromatosis type 2, Noonan syndrome with multiple lentigines, tuberous sclerosis complex, Sturge-Weber syndrome, and incontinentia pigmenti.

SUMMARY

Neurologists require a basic knowledge of and familiarity with a wide variety of neurocutaneous disorders because of the frequent involvement of the central and peripheral nervous systems. A simple routine skin examination can often open a broad differential diagnosis and lead to improved patient care.

Adult-Onset Hemorrhagic Quasi-Moyamoya Disease with Unilateral Steno-occlusive Lesion in a Patient with Neurofibromatosis Type 1

BACKGROUND

Quasi-moyamoya disease is a condition that occurs in association with a specific underlying condition or disease such as atherosclerotic disease or neurofibromatosis type 1 (NF1). Pediatric cases are frequently reported, and an ischemic and bilateral presentation is more common than a hemorrhagic and unilateral presentation.

CLINICAL PRESENTATION

A 39-year-old woman previously diagnosed with NF1 presented to our department with nausea and left hemiparesis. She was diagnosed with right temporal intracerebral hemorrhage by initial computed tomography. Subsequent angiography showed an occlusion of the terminal portion of the right internal carotid artery, and magnetic resonance imaging showed multiple flow voids in the right basal ganglia, suggesting quasi-moyamoya disease. The hematoma was surgically removed, and her neurological condition improved after the operation.

CONCLUSIONS

This is the first reported case of quasi-moyamoya disease with a rare combination of characteristics, including an adult-onset, hemorrhagic presentation and a unilateral lesion in a patient previously diagnosed with NF1.

Giant phaeochromocytoma presenting with an acute stroke: reappraising phaeochromocytoma surveillance for the neurofibromatosis type 1 phakomatosis

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder associated with reduced lifespan attributed largely to malignancy and vascular causes. One of the tumours associated with NF1 is phaeochromocytoma. The phaeochromocytoma has earned the moniker, a 'great mimicker', due to its varied means of presentation. We present a patient with NF1 who was diagnosed with a giant 20 cm phaeochromocytoma after suffering from an ischaemic stroke. Current guidelines do not advocate surveillance of phaeochromocytoma in asymptomatic patients with NF1, unlike other genetic syndromes associated with phaeochromocytoma. However, there is increasing evidence that this approach may not help in the early detection and treatment of this potentially life-threatening disease. Our patient remained hypertensive after surgery despite achieving biochemical cure. The suggested chronicity of the underlying tumour in our patient is a reminder to practising clinicians to rethink our strategy in identifying phaeochromocytoma in adults with NF1.

Neurofibromatosis type 1 is not associated with subarachnoid haemorrhage

BACKGROUND

The prevalence of intracranial aneurysms (IAs) has been proposed to be elevated in the patients with neurofibromatosis type 1 (NF1). Our aims were to determine the prevalence of NF1 in a large Finnish population based cohort of IA patients and, on the other hand, the occurrences of subarachnoid haemorrhage and unruptured intracranial aneurysms in a nationwide population-based cohort of NF1 patients and its matched ten-fold control cohort.

METHODS

The Kuopio IA Database (www.kuopioneurosurgery.fi) includes all ruptured and unruptured IA cases admitted to the Kuopio University Hospital (KUH) from its defined Eastern Finnish catchment population since 1980. In this registry-based study, we cross-linked the Kuopio IA database with the Finnish national registry covering all hospital diagnoses. The NF1 diagnoses of the 4543 patients with either saccular of fusiform IA were identified from 1969 to 2015 and verified from patient records. Our second approach was to analyze the occurrence of aneurysmal subarachnoid haemorrhage (aSAH) and unruptured IAs in a nationwide population-based database of 1410 NF1 patients and its ten-fold matched control cohort (n = 14030) using national registry of hospital diagnoses between 1987 and 2014.

RESULTS

One NF1 patient was identified among the 4543 IA patients. Three verified IA cases (one unruptured IA and two aSAH cases) were identified in the cohort of 1410 NF1 patients, with similar occurrences in the control cohort.

CONCLUSIONS

We found no evidence in our population-based cohorts to support the conception that NF1 is associated with IAs. Our results indicate that the incidence of aSAH is not elevated in patients with NF1. Further studies are required to confirm that there is no association between NF1 and unruptured IAs.

Stroke and Hypertension in Children and Adolescents

Hypertension is the single most important modifiable risk factor for adult stroke. Stroke mortality has significantly decreased over the last 5 decades; this decline has been mainly associated to improved blood pressure control. Though much less prevalent than in adults, stroke is an increasingly recognized cause of morbidity and mortality in children. Although hypertension has not been strongly identified as a risk factor in childhood stroke yet, there is preliminary evidence that suggests that elevated blood pressure may be associated with stroke in children. This review summarizes the literature that may link elevated blood pressure to the development of childhood ischemic and hemorrhagic stroke. The authors suggest that elevated blood pressure may be a significant risk factor that, alone or in combination with other multiple risk factors, leads to the development of stroke in childhood. It is therefore recommend that blood pressure be measured and assessed carefully in every child presenting with acute stroke.

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.

Neurovascular manifestations of connective-tissue diseases: A review

Patients with connective tissue diseases are thought to be at a higher risk for a number of cerebrovascular diseases such as intracranial aneurysms, dissections, and acute ischemic strokes. In this report, we aim to understand the prevalence and occurrences of such neurovascular manifestations in four heritable connective tissue disorders: Marfan syndrome, Ehlers-Danlos syndrome, Neurofibromatosis Type 1, and Loeys-Dietz syndrome. We discuss the fact that although there are various case studies reporting neurovascular findings in these connective tissue diseases, there is a general lack of case-control and prospective studies investigating the true prevalence of these findings in these patient populations. Furthermore, the differences observed in the manifestations and histology of such disease pathologies encourages future multi-center registries and studies in better characterizing the pathophysiology, prevalence, and ideal treatment options of neurovascular lesions in patents with connective tissue diseases.