A novel RAB39B mutation and concurrent de novo NF1 mutation in a boy with neurofibromatosis type 1, intellectual disability, and autism: a case report

BACKGROUND

Mutations in RAB39B at Xq28 causes a rare form of X-linked intellectual disability (ID) and Parkinson's disease. Neurofibromatosis type 1 (NF1) is caused by heterozygous mutations in NF1 occurring de novo in about 50% of cases, usually due to paternal gonadal mutations. This case report describes clinical and genetic findings in a boy with the occurrence of two distinct causative mutations in NF1 and RAB39B explaining the observed phenotype.

CASE PRESENTATION

Here we report a 7-year-old boy with multiple café-au-lait macules (CALMs) and freckling, severe macrocephaly, peculiar facial gestalt, severe ID with absent speech, epilepsy, autistic traits, self-harming, and aggressiveness. Proband is an only child born to a father aged 47. Parents did not present signs of NF1, while a maternal uncle showed severe ID, epilepsy, and tremors.By RNA analysis of NF1, we identified a de novo splicing variant (NM_000267.3:c.6579+2T>C) in proband, which explained NF1 clinical features but not the severe ID, behavioral problems, and aggressiveness. Family history suggested an X-linked condition and massively parallel sequencing of X-exome identified a novel RAB39B mutation (NM_171998.2:c.436_447del) in proband, his mother, and affected maternal uncle, subsequently validated by Sanger sequencing in these and other family members.

CONCLUSIONS

The case presented here highlights how concurrent genetic defects should be considered in NF1 patients when NF1 mutations cannot reasonably explain all the observed clinical features.

Are morphological and structural MRI characteristics related to specific cognitive impairments in neurofibromatosis type 1 (NF1) children?

INTRODUCTION

NF1 children have cognitive disorders, especially in executive functions, visuospatial, and language domains, the pathophysiological mechanisms of which are still poorly understood.

MATERIALS AND METHODS

A correlation study was performed from neuropsychological assessments and brain MRIs of 38 NF1 patients and 42 controls, all right-handed, aged 8-12 years and matched in age and gender. The most discriminating neuropsychological tests were selected to assess their visuospatial, metaphonological and visuospatial working memory abilities. The MRI analyses focused on the presence and location of Unidentified Bright Objects (UBOs) (1), volume analysis (2) and diffusion analysis (fractional anisotropy and mean diffusivity) (3) of the regions of interest including subcortical structures and posterior fossa, as well as shape analysis of subcortical structures (4). The level of attention, intelligence quotient, age and gender of the patients were taken into account in the statistical analysis. Then, we studied how diffusion and volumes parameters were associated with neuropsychological characteristics in NF1 children.

RESULTS

NF1 children present different brain imaging characteristics compared to the control such as (1) UBOs in 68%, (2) enlarged total intracranial volume, involving all subcortical structures, especially thalamus, (3) increased MD and decreased FA in thalamus, corpus callosum and hippocampus. These alterations are diffuse, without shape involvement. In NF1 group, brain microstructure is all the more altered that volumes are enlarged. However, we fail to find a link between these brain characteristics and neurocognitive scores.

CONCLUSION

While NF1 patients have obvious pathological brain characteristics, the neuronal substrates of their cognitive deficits are still not fully understood, perhaps due to complex and multiple pathophysiological mechanisms underlying this disorder, as suggested by the heterogeneity observed in our study. However, our results are compatible with an interpretation of NF1 as a diffuse white matter disease.

Durable Complete Response of a Recurrent Mesencephalic Glioblastoma Treated with Trametinib and Low-Dose Dabrafenib in a Patient with Neurofibromatosis Type 1

Patients with neurofibromatosis type 1 (NF1) have an increased lifetime risk for the development of nervous system tumors, including high-grade gliomas (glioblastoma). NF1 is associated with the loss of expression of neurofibromin 1 (NF1 gene product). This hyperactivates the mitogen-activated protein kinase pathway, leading to cellular proliferation and survival. MEK-inhibitor monotherapy is a promising treatment strategy in this setting, but is associated with distinct adverse events, most prominently cutaneous toxicity. We report the case of a young NF1 patient with a recurrent, heavily pretreated mesencephalic glioblastoma who was treated with the MEK-inhibitor trametinib (2 mg once daily). A partial response was documented, but unfortunately, he developed dose-limiting cutaneous toxicity (rash, paronychia). Based on interim results of a phase 2 trial in advanced BRAF^V600 wild-type melanoma indicating that a low dose of the BRAF-inhibitor dabrafenib is able to counter trametinib-related cutaneous toxicity, dabrafenib 50 mg twice daily was added. The cutaneous adverse events gradually recovered after addition of dabrafenib to trametinib. The patient eventually achieved a durable complete response, has excellent tolerance of his treatment and remains fully active.

Partial empty sella syndrome, GH deficiency and transient central adrenal insufficiency in a patient with NF1

PURPOSE

To describe the case of a 9-year-old male patient with neurofibromatosis type 1 (NF1), partial empty sella (PES), transient central adrenal insufficiency (CAI) and growth hormone (GH) deficiency (GHD) treated with recombinant GH (rGH).

METHODS

The diagnosis of GHD was established upon peak GH response <10 ng/mL following glucagon and clonidine stimulation tests. CAI was diagnosed when peak cortisol response was <18 μg/dL following 1 μg Synacthen test (ST) with normal ACTH levels.

RESULTS

The diagnosis of NF1 was made at the age of 1.5 year. The patient first attended our Department at the age of 4.5 years. He presented with short stature (height: 95 cm < 3rd percentile), macrocephaly, frontal bossing, café-au-lait spots and bilateral proptosis. His growth rate (GR) initially was 5.3 cm/year. Brain/pituitary MRI showed T2-hyperintensities typical for NF1 and PES with reduced pituitary gland height (3 mm). The pituitary function tests revealed GHD. During follow-up his imaging findings remained unchanged, while his GR decelerated. He was started on rGH at the age of 8.5 years. Within the following year he grew 8.7 cm in height and could preserve a normal GR thereafter. At the age of 10.3 years, he was diagnosed with CAI (maximum cortisol response post-1 μg ST: 13.1 μg/dL). Ηe received hydrocortisone for 1 year. A repeat 1 μg ST off hydrocortisone showed normal cortisol response. During follow-up, brain MRI findings remained stable, while his pituitary demonstrated normal size and signal intensity.

CONCLUSION

Empty sella and hypopituitarism may occur in the context of NF1. Short stature may be associated with GHD in the absence of intrasellar masses in affected individuals. Lifelong endocrine follow-up is recommended for all NF1 patients.

Spontaneous rupture of the pancreatic arcade artery caused by neurofibromatosis type 1 successfully treated using emergency transcatheter arterial embolization, partial intra-aortic balloon occlusion, and stent graft placement: a case report and review of the literature

Background

Vascular abnormalities in neurofibromatosis type 1 (NF1) are rare, but are the second leading cause of death in persons with NF1. In NF1 vasculopathy (NF-V), fatal bleeding due to a spontaneous arterial rupture sometimes occurs. Ruptured extracranial arteries in patients with NF1 often involve thoracic vessels, such as the intercostal and subclavian arteries; very few reports exist regarding the abdominal region. Herein, we present the first case of intraperitoneal bleeding due to spontaneous pancreatic arcade artery (PAA) rupture associated with NF1, successfully treated by transcatheter arterial embolization (TAE) combined with stent-graft placement and partial intra-aortic balloon occlusion (IABO).

Case presentation

A 40-year-old woman complained of back and abdominal pain. Upon admission, her blood pressure was 85/41 mmHg and heart rate was 129 beats/min. Computed tomography (CT) showed large intraperitoneal bleeding due to PAA rupture. After CT scanning, her systolic blood pressure decreased to 50 mmHg. Therefore, we performed emergency TAE with partial IABO. She was treated by TAE of the anterior superior pancreaticoduodenal artery, anterior inferior pancreaticoduodenal artery, and inferior pancreaticoduodenal artery. However, even after TAE, minor extravasation around the superior mesenteric artery continued, and her vital signs remained unstable. Stent-graft placement was selected to stop the haemorrhage, preserving normal blood flow of the superior mesenteric artery trunk. Excellent patency of the stent graft was confirmed on follow-up CT, and she was discharged on postoperative day 56.

Conclusion

PAA rupture associated with NF1 can be successfully treated by TAE combined with partial intra-aortic balloon occlusion, and stent-graft placement.

Multimodal evaluation of the cerebrovascular reserve in Neurofibromatosis type 1 patients with Moyamoya syndrome

Purpose

Moyamoya syndrome (MMS) is a rare intracranial arterial vasculopathy which can occur in neurofibromatosis type 1 (NF1) disease, representing a cause of cerebrovascular reserve (CVR) impairment, possibly leading to ischemic stroke. Here, we evaluated noninvasive imaging techniques used to assess CVR in MMS patients, describing clinical and imaging findings in patients affected by MMS-NF1.

Methods

Following strict inclusion and exclusion criteria, in this retrospective observational study, we evaluated imaging data of nine consecutive MMS-NF1 patients (M/F = 5/4, mean age: 12.6 ± 4.0). Subjects underwent a multimodal evaluation of cerebral vascular status, including intracranial arterial MR Angiography (MRA), MRI perfusion with dynamic susceptibility contrast (DSC) technique, and 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT.

Results

In 8 out 9 patients (88.8%, 6/8 symptomatic), time-to-peak maps were correlated with the involved cerebral hemisphere, while in 6 out 9 patients (66.6%, 5/6 symptomatic), mean transit time (MTT) maps showed correspondence with the affected cerebrovascular territories. Cerebral blood flow (CBF) calculated using DSC perfusion failed to detect the hypoperfused regions instead identified by SPECT-CBF in all patients, while MTT maps overlapped with SPECT-CBF data in all cases and time-to-peak maps in 60.0%.

Conclusions

Although SPECT imaging still represents the gold standard for CBF assessment, our results suggest that data obtained using DSC perfusion technique, and in particular MTT maps, might be a very useful and noninvasive tool for evaluating hemodynamic status in MMS-NF1 patients.

Electronic supplementary material

The online version of this article (10.1007/s10072-020-04574-4) contains supplementary material, which is available to authorized users.

Management of Proximal Thoracic Kyphoscoliosis with Early Myelopathy in a Young Adult with Neurofibromatosis Type 1: A Case Report and Review of Literature

INTRODUCTION

Neurofibromatosis (NF) 1 is associated with skeletal deformities. Scoliosis is seen in about 10-64% of NF-1 patients. NF-1 may be associated with dystrophic or non-dystrophic type of curve. There are technical difficulties in treating large dystrophic curve with proximal thoracic kyphoscoliosis in NF-1. This case report and subsequent review of literature attempts to provide a line of management for such difficult lesions.

MATERIALS AND METHODS

We present a case of 22-year-old male with NF-1 who came to us with gradually progressive upper back deformity and signs of early myelopathy for 2-3 months. The patient had a 100° proximal thoracic kyphosis and 100° scoliosis with no neurological deficit and brisk reflexes. A single stage posterior fixation with three column osteotomy at the apex of the curve was performed.

RESULTS

The kyphosis was corrected to 65° from 100, the scoliosis was corrected to 60° from 100. Clinically, the hump in the upper back was visibly reduced. At 1-year follow-up, the patient remained asymptomatic with no loss of correction and implant breakage on X-ray.

CONCLUSION

Large dystrophic proximal thoracic kyphoscoliosis is a difficult lesion to treat and can be managed with an all posterior approach, achieving good cosmetic and neurological outcomes, as demonstrated by this case.

The Use of MEK Inhibitors in Neurofibromatosis Type 1-Associated Tumors and Management of Toxicities

Early-phase clinical trials using oral inhibitors of MEK, the mitogen-activated protein kinase kinase, have demonstrated benefit for patients with neurofibromatosis type 1 (NF1)-associated tumors, particularly progressive low-grade gliomas and plexiform neurofibromas. Given this potential of MEK inhibition as an effective medical therapy, the use of targeted agents in the NF1 population is likely to increase substantially. For clinicians with limited experience prescribing MEK inhibitors, concern about managing these treatments may be a barrier to use. In this manuscript, the Clinical Care Advisory Board of the Children's Tumor Foundation reviews the published experience with MEK inhibitors in NF1 and outlines recommendations for side-effect management, as well as monitoring guidelines. These recommendations can serve as a beginning framework for NF providers seeking to provide the most effective treatments for their patients. IMPLICATIONS FOR PRACTICE: Neurofibromatosis type 1 (NF1) clinical care is on the cusp of a transformative shift. With the success of recent clinical trials using MEK inhibitors, an increasing number of NF1 patients are being treated with MEK inhibitors for both plexiform neurofibromas and low-grade gliomas. The use of MEK inhibitors is likely to increase substantially in NF1. Given these changes, the Clinical Care Advisory Board of the Children's Tumor Foundation has identified a need within the NF1 clinical community for guidance for the safe and effective use of MEK inhibitors for NF1-related tumors. This article provides a review of the published experience of MEK inhibitors in NF1 and provides recommendations for monitoring and management of side effects.

Pleomorphic Xanthoastrocytoma of the Pineal Region in a Pediatric Patient With Neurofibromatosis Type 1

Background: Pleomorphic xanthoastrocytoma (PXA) is a rare and often focal glioma that most commonly affects children and young adults. Lesions are preferentially supratentorial and superficial, although infratentorial masses have been described, along with occasional involvement of the leptomeninges. The World Health Organization (WHO) categorizes these tumors as grade II, with surgical resection carrying a favorable prognosis. However, these tumors may undergo malignant degeneration and must be identified for appropriate treatment and prognosis. PXA has been associated with neurofibromatosis type 1 (NF1), although it is not the classic phenotype of NF1. We present a novel report of PXA, atypically located in the pineal region of a patient with a history of NF1.

Case Report: A 17-year-old male with a history of NF1 presented with 1 month of bifrontal headaches. Magnetic resonance imaging was significant for a heterogeneous tectal mass, suspicious for a glioma extending to the fourth ventricle and causing displacement of the cerebral aqueduct without obstructive hydrocephalus. Following an infratentorial-supracerebellar approach for tumor resection, histopathology confirmed a low-grade variable neoplasm consistent with PXA. Postoperative imaging confirmed gross total resection with no evidence of recurrence at 9 months postoperatively.

Conclusion: To our knowledge, this case is the fifth report of pineal PXA and the first associated with NF1. Because PXA presents similarly to other NF1-related intracranial tumors, careful diagnosis via immunohistochemistry is imperative. Gross tumor resection is usually curative; however, PXA has the propensity to undergo malignant degeneration and may require adjuvant treatment.

Myelodysplastic syndromes in a pediatric patient with Cri du Chat syndrome with a ring chromosome 5

Few hematological complications have previously been reported in association with Cri du Chat syndrome (CdCS). A case of myelodysplastic syndromes (MDS) in a pediatric patient with CdCS is herein presented. A 17-year-old female with CdCS caused by ring chromosome 5 was admitted to the hospital for investigation of a 1-month history of anemia. Based on the morphological findings of bone marrow, the patient was diagnosed with refractory cytopenia with multilineage dysplasia. The risk group was classified as intermediate-1 in the International Prognostic Scoring System (IPSS), and low in the revised IPSS. Assessment by microarray comparative genomic hybridization (CGH) identified the breakpoints of ring chromosome 5 as 46,XX,r(5)(p14.3q35.3). This revealed that the 5q terminal deletion did not include the common deleted region of MDS with del(5q). Treatment with azacitidine was initiated to control disease progression and improve quality of life. At baseline, the patient had a mean transfusion requirement of 3 units/month, which decreased to 2 units/month after six cycles of azacitidine and to 1 unit/month after 10 cycles of azacitidine. Cytopenia observed in the presented case seemed irrelevant to ring chromosome 5 which is the causative cytogenetic abnormality of CdCS, and further analyses may be needed to clarify the pathogenesis.

Increased epileptogenicity in a mouse model of neurofibromatosis type 1

RATIONALE

Neurofibromatosis type 1 (NF1) is associated with higher rates of epilepsy compared to the general population. Some NF1 patients with epilepsy do not have intracranial lesions, suggesting the genetic mutation itself may contribute to higher rates of epilepsy in these patients. We have recently demonstrated increased seizure susceptibility in the Nf1^+/- mouse, but it is unknown whether this model displays altered epileptogenicity, as has been reported in patients with NF1. The aim of this study was to determine whether the Nf1^+/- mouse is more susceptible to electrical kindling-induced epileptogenesis.

METHODS

Young male or female adult Nf1^+/- or Nf1^+/+ (wild-type; WT) mice were implanted with electrodes for neocortical or hippocampal kindling paradigms. Neocortical kindling was performed for 40 stimulation sessions followed by baseline EEG monitoring to detect possible SRSs. Hippocampal kindling was performed with a modified extended kindling paradigm, completed to a maximum of 80 sessions to try to induce spontaneous repetitive seizures (SRSs). Western blot assays were performed in naïve and kindled mice to compare levels of Akt and MAPK (ERK1/2), proteins downstream of the NF1 mutation.

RESULTS

The average initial neocortical after-discharge threshold (ADT) was significantly lower in the Nf1^+/- group, which also required fewer stimulations to reach stage 5 seizure, had greater average seizure severity across all kindling sessions, had a greater number of convulsive seizures, and had a faster progression of after-discharge duration and Racine score during kindling. No WT mice exhibited SRS after neocortical kindling, versus 33% of Nf1^+/- mice. The average initial hippocampal ADT was not significantly different between the WT and Nf1^+/- groups, nor was there a difference in the number of stimulations required to reach the kindled state. The WT group had a significantly higher average seizure severity across all kindling sessions as compared with the Nf1^+/- mice. The WT group also had faster progression of the Racine seizure score over the kindling sessions, mainly due to a faster increase in seizures severity early during the kindling process. However, SRSs were seen in 50% of Nf1^+/- mice after modified extended kindling and in no WT mice. Western blots showed hippocampal kindling increased the ratio of phosphorylated/total Akt in both the WT and Nf1^+/- mice, while neocortical kindling led to increased ratios of phosphorylated/total Akt and MAPK in Nf1^+/- mice only.

CONCLUSIONS

We have demonstrated for the first time an increased rate of epileptogenesis in an animal model of NF1 with no known macroscopic/neoplastic brain lesions. This work provides evidence for the genetic mutation itself playing a role in seizures and epilepsy in patients with NF1, and supports the use of the Nf1^+/- mouse model in future mechanistic studies.

Isolated colonic neurofibroma, a rare tumor: A case report and review of literature

BACKGROUND

Neurofibromas are tumors comprised of peripheral nerve sheath and connective tissue components. They can occur sporadically or as part of familial syndromes such as neurofibromatosis type 1. Isolated colonic neurofibroma without systemic manifestations is a rarely reported clinical entity. Here we present a case of a 51 years old male with an isolated colonic neurofibroma seen on a screening colonoscopy.

CASE SUMMARY

Fifty-one years old male who was otherwise healthy without a significant family history of cancer underwent a screening colonoscopy and was found have a 2.3 cm × 1.4 cm lesion in the colon. Tissue biopsy revealed a spindle cell tumor. Magnetic resonance imaging of the pelvis was negative for adenopathy. He underwent an endoscopic ultrasound that showed an ill-defined avascular lesion of mixed echogenicity measuring 2.8 cm × 15.2 cm in the submucosa with no communication with muscularis mucosa or propria. Immunohistochemistry staining of the tumor was strongly positive for S100, with rare penetrating axons deep within the tumor. Tumor cells were negative for c-kit and desmin and had low Ki-67 index. These findings were consistent with a solitary colonic submucosal neurofibroma. A detailed history and physical examination did not reveal any evidence of extraintestinal neurofibromatosis. He underwent transanal surgical resection of the tumor. The patient tolerated the procedure well without any complications.

CONCLUSION

While neurofibromas have been well described in literature, an isolated colonic neurofibroma is a rare pathological entity. Malignant transformation of neurofibromas has been reported in patients with neurofibromatosis syndromes. We report a case of isolated colonic neurofibroma and highlight the importance of resection due to the increased risk of tumorigenesis.

Clinical and neuroradiological characterisation of spinal lesions in adults with Neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) manifests itself in many ways in the spine. This study aims to report the types of spinal lesions, clinical and demographic data in a large cohort from a complex NF1 centre. The characteristics of those with spinal neurofibromatosis, where neurofibromas are present on every spinal nerve root, were sought for comparison with the wider group of NF1 patients. This is a retrospective review of MDT minutes of 303 patients from a UK NF1 centre and the largest reported series of NF1 patients based on radiological data. Prevalence of each symptom and lesion was calculated and statistically significant associations were established. The most reported findings were cutaneous lesions (44.9%) and neurological deficit (27.4%). 28.4% had dural ectasia, 52.5% had some form of spinal deformity. 57.8% had spinal nerve root tumours, the most common of which were at C2. The most progressive lesions were spinal nerve root tumours (29.1%). The only statistically significant association found was between dural ectasia and spinal deformity (P < 0.003), where dural ectasia is associated with a 32.6% increase in spinal deformity incidence. This is the largest descriptive study of spinal lesions in NF1. Spinal tumours and spinal deformity are prevalent in NF1. The predilection of spinal tumours for flexible spinal regions suggests that repetitive movement might be an important factor in pathogenesis. Physicians and patients should be alert to the observation that although many spinal neurofibromatosis patients display no neurological deficit, they often have significant lesions which require monitoring and sometimes surgery.

Jaffe-Campanacci syndrome or neurofibromatosis type 1: a case report of phenotypic overlap with detection of NF1 gene mutation in non-ossifying fibroma

Background

Jaffe-Campanacci syndrome is characterized by multiple non-ossifying fibromas, café-au-lait macules and giant cell granulomas of the jaw. Even if the association between all these peculiar features and neurofibromatosis type 1 have been described, it has not yet been clarified whether Jaffe-Campanacci syndrome represents a distinct entity or it can be regarded as a neurofibromatosis type 1 subtype.

Case presentation

The patient here described is a young boy, who fulfilled the clinical diagnostic criteria for both syndromes. He had a complex clinical history with café-au-lait macules, axillary and inguinal freckling, multiple non-ossifying fibromas, giant-cell granuloma of the jaw, neurofibromas, plexiform fibroma, ocular Lisch nodules, optic chiasmatic- hypothalamic glioma, pseudarthrosis, scoliosis, short stature, vascular anomalies, seizures. Molecular analysis of the NF1 gene both on blood cells and non-ossifying fibroma’s biopsy tissue allowed the detection of a novel variant within the coding region, NM_000267.3:c.2789_2791delATC(p.Tyr930_Pro931delinsSer), with loss of heterozygosity (second hit mutation) in the non-ossifying fibroma.

Conclusion

This result indicates that every patient with clinical features of Jaffe-Campanacci syndrome should be further evaluated to detect features related to neurofibromatosis type 1 and genetically investigated for mutations in the NF1 gene, since this could lead to a definite diagnosis, but also could clarify and quantify the real genotype-phenotype overlap between neurofibromatosis type 1 and Jaffe-Campanacci syndrome.

Ocular surface involvement in patients with neurofibromatosis type 1 syndrome

PURPOSE

The aim of this study is to evaluate ocular surface morphological and functional changes in patients with neurofibromatosis type 1 (NF1).

METHODS

Twenty-eight patients with NF1 and 14 healthy subjects were included in this study. All participants underwent a medical history collection, a complete ophthalmological examination including slit lamp exam and assessment of best-corrected visual acuity (BCVA), corneal sensitivity, and lacrimal function (Schirmer test and fluorescein tear break-up time test). Corneal nerves' morphology and endothelial cells density were evaluated by in vivo corneal confocal microscopy (IVCM). Tear and conjunctiva epithelium samples were collected to evaluate nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) tear levels and conjunctival expression of their receptors TrkA and p75NTR.

RESULTS

Patients with NF1 showed a significant decrease of FTBUT when compared with healthy subjects (p < 0.001). Corneal sensitivity was ≤ 50 mm in 46% of NF1 patients. IVCM showed a significant increase of corneal nerve branching and of corneal endothelial cells density. No significant difference was observed between the two groups on NGF and BDNF tear levels and conjunctival expression of their receptors.

CONCLUSION

This study demonstrated the presence of ocular surface changes in NF-1 patients including decrease of tear stability and of corneal sensitivity. Patients with NF1 also showed changes of corneal endothelial cells' density.

Neurofibromatosis type 1 associated with hypophosphatemic osteomalacia due to hypersecretion of fibroblast growth factor 23: a case report

BACKGROUND

Neurofibromatosis type 1 is characterized by multiple café au lait spots and cutaneous and plexiform neurofibromas, and is one of the most common autosomal dominant hereditary disorders caused by mutations of the neurofibromatosis type 1 tumor suppressor gene. Osteomalacia in neurofibromatosis type 1 is very rare and is characterized by later onset in adulthood. In humans, fibroblast growth factor 23, which is a causative factor of tumor-induced osteomalacia, is not only a paracrine and autocrine factor, but is also a physiological regulator of phosphate balance in normal serum.

CASE PRESENTATION

Our patient was a 65-year-old Japanese woman whose neurofibromas began to appear when she was in elementary school. At age 28, she was diagnosed as having neurofibromatosis type 1. A spinal compression fracture and multiple rib fractures were identified in 2012 and 2017, respectively. Her laboratory findings revealed hypophosphatemia due to renal phosphate wasting and a high serum level of fibroblast growth factor 23. Neurofibromas located on the surface of her right forearm and left upper arm, in which a slight abnormal accumulation of tracers was observed on ¹¹¹indium-pentetreotide scintigraphy, were surgically removed, but there was no improvement in hypophosphatemia or serum fibroblast growth factor 23 after surgery. Therefore, we administered eldecalcitol, which also failed to produce improvement in abnormal data. Subsequent combination with dibasic calcium phosphate hydrate led to improvement in some of the abnormalities, including hypophosphatemia. Immunohistochemical staining using anti-human fibroblast growth factor 23 antibody revealed slightly positive results, however, only one out of three amplifications of the fibroblast growth factor 23 gene was observed by real-time polymerase chain reaction, and no clear fibroblast growth factor 23 gene expression in the resected neurofibromas could be confirmed.

CONCLUSIONS

We here describe a first rare case of a 65-year-old woman with neurofibromatosis type 1 associated with hypophosphatemic osteomalacia in which a high serum fibroblast growth factor 23 level was confirmed.

Does neurofibromatosis 1 status impact outcomes for pediatric/young adults undergoing spinal fusion?

Background:

Although spinal deformities are common in patients with neurofibromatosis type 1 (NF1), there is a paucity of data as to how this impacts outcomes of spinal fusion surgery in pediatric/young adult patients.

Methods:

Using the Nationwide Inpatient Sample (2005–2014) for all patients undergoing spinal fusion ≤26 years of age, we compared the following factors: demographics, comorbidities, and perioperative variables (e.g., between NF1 vs. non-NF1, and between NF1 and propensity score (PS)-matched non- NF1 spinal fusion patients) using univariate hypothesis tests and multivariate regression analyses. Our main interest focused on length of stay, complication rates, adverse postoperative events, and incidence of nonroutine discharges.

Results:

In this study, 238 (0.92%) NF1 spine patients were compared to 25,558 (99.08%) non-NF1 spine patients. NF1 fusion patients were younger, included fewer females, and were more likely to be on Medicaid. Perioperatively, NF1 patients underwent more anterior approaches, had more vertebrae fused, required more transfusions, had a longer length of stay (LOS), and were less likely to be discharged home. However, after PS- matching, all differences between NF1 and non-NF1 groups disappeared were similar (P > 0.05). In PS-matched multivariate analyses, NF1-status was not a significant independent predictor of length of stay or nonroutine discharge disposition.

Conclusion:

NF1-status was, therefore, not an independent predictor of complications, adverse postoperative events, longer LOS, or nonroutine hospital discharge in this cohort analysis. Further prospective studies are necessary to understand how outcomes in patients with NF1 compare to non-NF1 pediatric and young adult patients.

Chinese patient with neurofibromatosis-Noonan syndrome caused by novel heterozygous NF1 exons 1-58 deletion: a case report

BACKGROUND

Neurofibromatosis-Noonan syndrome (NFNS) is a rare autosomal dominant hereditary disease. We present a case of NFNS due to the heterozygous deletion of exons 1-58 of the NF1 gene on chromosome 17 in a 15-month-old boy.

CASE PRESENTATION

A 15-month-old boy was admitted for motor and language developmental delay, numerous café-au-lait spots, hypertelorism, left blepharoptosis, pectus excavatum, cryptorchidism, secondary atrial septal defect, and UBOs (undefined bright objects) revealed by cranial MRI T2FLAIR in basal ganglia and cerebellum. Using whole exome sequencing, we identified a de novo heterozygous deletion including exons 1-58 of the NF1 gene.

CONCLUSION

Although genetic tests are useful tools for diagnosis of NFNS, NF1, or NS, comprehensive analysis of genetic factors and phenotypes is indispensable in the clinical practice. To the best of our knowledge, this case presents the first Chinese NFNS case due to NF1 defects, and the NF1 exons 1-58 deletion-related phenotype is unlike any other reported case.

Neovascular glaucoma in a pediatric patient with neurofibromatosis type 1: a case report

Background

To report a case of a young patient with neurofibromatosis type 1 (NF1).

Methods: Here we review the treatment administered to a 7-year-old NF1 patient with neovascular glaucoma as the primary diagnosis.

Case presentation

A 7-year-old boy developed visual loss in the right eye associated with periocular pain and ipsilateral headache that had persisted for 1 week. The patient’s condition did not improve after treatment with topical or systemic glaucoma medications. Fundus examination of the right eye showed superotemporal retinal vasoproliferative tumors (RVPT). Near-infrared reflectance scans of the left eye’s fundus revealed bright patchy regions, scattered across the posterior pole; systemic examination showed café-au-lait spots all over the patient’s body. The patient had a clear family history. Genetic testing confirmed NF1. The right eye was treated with intravitreal ranibizumab injection, retinal lesion cryotherapy, and transscleral ciliary body photocoagulation. After treatment, RVPT scarring was observed. The patient’s intraocular pressure remained within normal limits.

Conclusions

We report a rare case of neurofibromatosis in a pediatric patient with neovascular glaucoma accompanied by RVPT. We suggest that evaluations of young patients with neovascular glaucoma should include careful attention to the overall condition of the patient and his/her parents, as well as family history. If necessary, NF1 molecular testing should be performed to avoid a missed diagnosis or misdiagnosis.

Ask-Upmark kidney in a girl with neurofibromatosis type 1

Ask-Upmark kidney (AUK) is a scarred segment of the kidney, characterized by formation of primitive tubular and glomerular structures, and sporadically diagnosed as a cause of hypertension (HTN). A 6-year-old girl with neurofibromatosis type 1 (NF1) and moyamoya syndrome had severe HTN. Based on past history, she had HTN at the age of 1.5 years. Laboratory examination revealed slightly elevated plasma and renal venous renin activity without lateralization. No evidence of pheochromocytoma, or coarctation of the aorta was found. Contrast-enhanced computed tomography (CT) showed an area of hypoperfusion in the upper and middle poles with reduced size of the right kidney. The results of dimercaptosuccinic acid scintigraphy were in accordance with those of contrast-enhanced CT. Selected renal arteriography revealed a paucity of peripheral vascularity in the same parts of the right kidney. In the absence of a history of urinary tract infection and vesicoureteral reflux by cystography, we presumed that the severe HTN may be due to segmental hypoplasia of the kidney, AUK, with a possible contribution from NF1. Although renal artery stenosis and pheochromocytoma are well-known causes of HTN in NF1, this case demonstrates that HTN can be caused by AUK in patients with NF1.

Upregulated immuno-modulator PD-L1 in malignant peripheral nerve sheath tumors provides a potential biomarker and a therapeutic target

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare aggressive sarcomas with poor prognosis. More than half of MPNSTs develop from benign precursor tumors associated with neurofibromatosis type 1 (NF1) which is a tumor suppressor gene disorder. Early detection of malignant transformation in NF1 patients is pivotal to improving survival. The primary aim of this study was to evaluate the role of immuno-modulators as candidate biomarkers of malignant transformation in NF1 patients with plexiform neurofibromas as well as predictors of response to immunotherapeutic approaches.

METHODS

Sera from a total of 125 NF1 patients with quantified internal tumor load were included, and 25 of them had MPNSTs. A total of six immuno-modulatory factors (IGFBP-1, PD-L1, IFN-α, GM-CSF, PGE-2, and AXL) were measured in these sera using respective ELISA.

RESULTS

NF1 patients with MPNSTs had significantly elevated PD-L1 levels in their sera compared to NF1 patients without MPNSTs. By contrast, AXL concentrations were significantly lower in sera of NF1-MPNST patients. IGFBP-1 and PGE2 serum levels did not differ between the two patient groups. IFN-α and GM-CSF were below the detectable level in most samples.

CONCLUSION

The immuno-modulator PD-L1 is upregulated in MPNST patients and therefore may provide as a potential biomarker of malignant transformation in patients with NF1 and as a response predictor for immunotherapeutic approaches.

Expanding the Noonan spectrum/RASopathy NGS panel: Benefits of adding NF1 and SPRED1

Background

RASopathies are a group of disorders caused by disruptions to the RAS‒MAPK pathway. Despite being in the same pathway, Neurofibromatosis Type 1 (NF1) and Legius syndrome (LS) typically present with phenotypes distinct from Noonan spectrum disorders (NSDs). However, some NF1/LS individuals also exhibit NSD phenotypes, often referred to as Neurofibromatosis‐Noonan syndrome (NFNS), and may be mistakenly evaluated for NSDs, delaying diagnosis, and affecting patient management.

Methods

A derivation cohort of 28 patients with a prior negative NSD panel and either NFNS or a suspicion of NSD and café‐au‐lait spots underwent NF1 and SPRED1 sequencing. To further determine the utility and burden of adding these genes, a validation cohort of 505 patients with a suspected RASopathy were tested on a 14‐gene RASopathy‐associated panel.

Results

In the derivation cohort, six (21%) patients had disease‐causing NF1 or SPRED1 variants. In the validation cohort, 11 (2%) patients had disease‐causing variants and 15 (3%) had variants of uncertain significance in NF1 or SPRED1. Of those with disease‐causing variants, 5/17 only had an NSD diagnosis.

Conclusions

Adding NF1 and SPRED1 to RASopathy panels can speed diagnosis and improve patient management, without significantly increasing the burden of inconclusive results.

Role of visual evoked potentials and optical coherence tomography in the screening for optic pathway gliomas in patients with neurofibromatosis type I

PURPOSE

The purpose of the present study was to compare visual function assessment, visual evoked potential, and optical coherence tomography with measurement of retinal nerve fiber layer thickness for the diagnosis of optic pathway glioma in children with neurofibromatosis type 1.

METHODS

This retrospective observational study included patients with neurofibromatosis type 1 who underwent brain magnetic resonance imaging scan, visual evoked potential study, and peripapillary retinal nerve fiber layer evaluation by optical coherence tomography. Patients were tested with pattern-reversal visual evoked potential and with flash visual evoked potential in case of poor cooperation. Optical coherence tomography was performed with HRA Spectralis (Heidelberg Engineering, Heidelberg, Germany). The area under the curve of receiver operating characteristic curves was used to evaluate the accuracy of each parameter for diagnosing optic pathway glioma.

RESULTS

In all, 110 patients with neurofibromatosis type 1 were included in the study. Fifty of them had an optic pathway glioma diagnosed with magnetic resonance imaging, while 60 did not. Global retinal nerve fiber layer thickness demonstrated the highest diagnostic power for discriminating patients with and without optic pathway glioma (area under the curve = 0.758, sensitivity = 65.3%, specificity = 83.3%), followed visual acuity (area under the curve = 0.723, sensitivity = 51.1%, specificity = 91.7%) and P100 of visual evoked potential (area under the curve = 0.712, sensitivity = 69.6%, specificity = 63.8%).

CONCLUSION

The results of the present study showed that the measurement of retinal nerve fiber layer thickness was the most efficient test for discriminating patients with and without optic pathway glioma. Brain magnetic resonance imaging remains the gold standard to confirm the diagnosis of optic pathway glioma. Longitudinal studies are required to define if the early detection of tumors with optical coherence tomography could prevent vision loss and morbidity.

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.

Lumbar artery aneurysm: A rare manifestation of vasculopathy in a patient with neurofibromatosis type 1

Lumbar artery aneurysms are rare but important to diagnose, since rupture can have serious consequences due to life-threatening hemorrhage. A 49-year-old male with Neurofibromatosis type 1 (NF-1) was admitted to the emergency room with abrupt onset of severe abdominal pain. Ultrasound examination was normal, noncontrast CT revealed a tapered retroperitoneal mass adjacent to the right psoas muscle. A multiphased contrast-enhanced CT scan raised suspicion of an arterial lumbar aneurysm and was confirmed by selective catheter based angiography. The patient underwent successful treatment with endovascular coiling and the patient was discharged within a few days after an uneventful course.