Bony orbital morphology in neurofibromatosis type 1 (NF1)

Sphenoid Bone Pneumatisation on Lateral Cephalograms of Patients With Neurofibromatosis Type 1

BACKGROUND/AIM

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disease that causes tumors and many developmental disorders, e.g., cranial dysplasia. The purpose of this retrospective study was to analyse the pneumatisation of the sphenoid bone in NF1.

PATIENTS AND METHODS

The anonymised lateral cephalograms of 166 NF1 patients and 166 age- and sex-matched controls were examined for anterior-posterior sphenoid pneumatisation. The patient group analysis considered whether the patients had been affected by a facial plexiform neurofibroma (FPNF).

RESULTS

Sphenoid pneumatisation was significantly lower in NF1 patients than in controls [odds ratio (OR)=0.184; 95%CI=0.11-0.32; p<0.001]. A FPNF statistically significantly reduced sinus formation in patients (OR=0.38; p=0.002).

CONCLUSION

The condition 'NF1' has an effect on sphenoid pneumatisation. The findings are relevant for planning surgical procedures in this region and confirm current concepts to evaluate NF1 as a histogenesis control gene. The examination technique and basis of calculation presented here are easy-to-use and low-irradiation exposure instruments for screening for differences in sphenoid bone pneumatisation in defined populations.

Evaluation of racial disparities in pediatric optic pathway glioma incidence: Results from the Surveillance, Epidemiology, and End Results Program, 2000-2014

BACKGROUND

Racial predilection to pediatric cancer exists; however optic pathway glioma (OPG) risk differences by race/ethnicity are undefined. We estimated differences in OPG incidence across racial/ethnic groups in a multi-state cancer surveillance registry in the United States.

METHODS

OPG data were obtained from the Surveillance, Epidemiology, and End Results (SEER-18) Program, 2000-2014. Race/ethnicity was categorized as: White; Black; Asian; Other; and Latino/a ("Spanish-Hispanic-Latino"). Latino/a included all races, while all other categories excluded those identified as Latino/a. Age-adjusted incidence rates and rate ratios (IRR) with 95% confidence intervals (CIs) were generated in SEER-STAT (v8.3.4).

RESULTS

Data on 709 OPG cases ages 0-19 were abstracted from SEER-18. Minority children experienced lower age-adjusted OPG incidence rates compared to White children (IRR_Black = 0.38, 95% CI: 0.28-0.50; IRR_Asian = 0.41, 95% CI: 0.29-0.58; and IRR_Latino/a = 0.39, 95% CI: 0.32-0.48). In subgroup analyses among the highest risk age categories (0-4, 5-9), minority children experienced lower incidence rates compared to White children. Specific patterns for Latinos/as also emerged. Latino/a children ages 0-4 experienced the lowest incidence rates of all racial/ethnic groups compared to Whites (0.24 per 100,000 person-years versus 0.66 per 100,000 person-years, respectively), whereas among those ages 5-9, Black and Asian children experienced the lowest incidence rates (0.08 per 100,000 person-years each).

CONCLUSIONS

Incidence of OPGs was highest among White children. This study represents one of the largest to assess differences in OPG susceptibility by race/ethnicity. These findings may inform future studies that seek to evaluate modifying factors for this pediatric tumor including tumorigenesis, treatment, outcome, and long-term late effects.

A lateral cephalometry study of patients with neurofibromatosis type 1

PURPOSE

Neurofibromatosis type 1 (NF1) is an autosomal dominant transmitted tumour suppressor syndrome and also a bone disease. Osseous dysplasia affecting the craniofacial region is characteristic of NF1. The aim of this study was to analyse the lateral cephalograms of NF1 patients in comparison to individuals who were not affected by this condition in order to describe the skeletal phenotype of NF1 in more detail.

MATERIALS AND METHODS

The study comprises the lateral cephalograms of 172 patients with established NF1 diagnoses (female = 85, male = 87). NF1 patients were distinguished by radiological and/or histological findings of the facial region suggestive of plexiform neurofibroma (PNF) or disseminated cutaneous NF (DNF). The analysed radiographs of a collection of 29 healthy volunteers with ideal occlusion served as controls. The focus of this analysis was cephalometrically defined angles.

RESULTS

Cephalometric analyses of patients with DNF did not differ from those of controls for the vast majority of parameters. However, the measurement results of patients with PNF differed significantly from those of healthy volunteers and patients with DNF. The number of trigeminal nerve branches affected in PNF patients had an effect on the measurement results.

CONCLUSION

Lateral cephalograms revealed no significant alteration of the facial skeleton in NF1 patients as compared to controls. Indeed, the stigma of a so-called 'NF1 facies' cannot be derived from the cephalometric findings presented. Notably, a wide range of deviating readings were recorded for individuals with facial PNF. Clinicians who treat patients with NF1 should be aware of deviations from cephalometric standards on lateral cephalograms in NF1 patients, especially when craniofacial surgical procedures are planned. Some of these findings, particularly asymmetries of the facial skeleton, could be indicators of an associated PNF.

Associations between allergic conditions and pediatric brain tumors in Neurofibromatosis type 1

Individuals with Neurofibromatosis type 1 (NF1) are at increased risk for pediatric brain tumors (PBTs), especially optic gliomas; however, factors influencing their development are largely unknown. Extensive research suggests that allergic conditions protect against brain tumors, particularly gliomas in individuals without NF1. In this large cross-sectional study, we employed two different data sources to evaluate evidence for the hypothesis that allergic conditions (allergies, asthma, and eczema) may protect against PBT development in individuals with NF1. We used self- and parent/legal guardian reported questionnaire data from participants in the NF1 Patient Registry Initiative (NPRI, n = 1660) born from 1933 to 2014 to ascertain allergic condition and PBT diagnosis histories. Medical records (MRs) of 629 NF1 patients at a large medical center born from 1930 to 2012 were also reviewed for PBT and allergic condition diagnoses to evaluate additional evidence for our hypothesis. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between allergic condition diagnoses and PBTs. Both data sources provided limited to no support for a protective effect of allergies or eczema on PBT development. Non-significant inverse associations between asthma and PBTs were observed (NPRI: OR = 0.80, 95% CI 0.55-1.17; MR: OR = 0.71, 95% CI 0.40-1.28) with stronger associations for optic gliomas specifically. Additionally, a significant inverse association was observed in an NPRI subgroup analysis where the reported asthma diagnosis age was younger than the reported PBT diagnosis age (OR = 0.57; 95% CI 0.36-0.89). Our study supports the hypothesis that asthma protects against PBT development in NF1.

Peri-gestational risk factors for pediatric brain tumors in Neurofibromatosis Type 1

BACKGROUND

Individuals with Neurofibromatosis Type 1 (NF1) are strongly predisposed to developing pediatric brain tumors (PBTs), especially optic pathway gliomas (OPGs). Although developmental factors have been implicated in the origins of PBTs in both human and animal studies, associations between early-life factors and PBTs have not been evaluated in individuals with NF1. Our objective was to evaluate associations between peri-gestational characteristics and PBTs in this population.

METHODS

We conducted a cross-sectional study, ascertaining questionnaire and medical record data for 606 individuals<18years old who enrolled in the NF1 Patient Registry Initiative (NPRI) from 6/9/2011-6/29/2015. One hundred eighty-four individuals had reported PBT diagnoses, including 65 who were identified with OPG diagnoses. Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between PBT and OPG diagnoses and peri-gestational characteristics (prematurity, birth weight, parental age, plurality, family history of NF1, assisted reproductive technology, maternal vitamin supplementation, and parental smoking).

RESULTS

We observed no significant associations between any of the assessed characteristics and PBTs overall or OPGs with the exception of birth weight. After controlling for potential confounding variables, we observed a significant positive association between birth weight quartile and OPGs with a HR of 3.32 (95% CI 1.39-7.94) for the fourth (≥3915.5g) compared to the first (≤3020g) quartile (p for trend=0.001).

CONCLUSIONS

Consistent with results for PBTs in the general population, these results suggest that higher birth weights increase OPG risk in individuals with NF1.

Racial/Ethnic Differences in Pediatric Brain Tumor Diagnoses in Patients with Neurofibromatosis Type 1

OBJECTIVE

To evaluate evidence for differences in pediatric brain tumor diagnoses by race and ethnicity using a cross-sectional study design in individuals with neurofibromatosis type 1 (NF1).

STUDY DESIGN

Subjects with NF1 were ascertained from the NF1 Patient Registry Initiative and through a clinical record database of patients at a large academic medical center. Logistic regression was employed to calculate ORs and 95% CIs to analyze differences in the odds of brain tumor diagnosis by race (White, Black, Asian, other/unknown) and ethnic (Hispanic vs non-Hispanic) groups.

RESULTS

Data from a total of 1546, 629, and 2038 individuals who were ascertained from the NF1 Patient Registry Initiative, clinical records, and pooled datasets were analyzed, respectively. After adjusting for birth year, we observed a significantly reduced odds of brain tumor diagnoses in individuals self-identified or clinically reported as Black (OR = 0.13, 95% CI 0.05-0.31), Asian (OR = 0.15, 95% CI 0.04-0.64), and other/unknown (OR = 0.61, 95% CI 0.41-0.93) race compared with those with reported as White race. There was no significant difference in the odds of pediatric brain tumor diagnosis by Hispanic ethnicity.

CONCLUSIONS

Consistent with prior smaller studies, these data suggest that pediatric brain tumor diagnoses vary by race in individuals with NF1. Reasons underlying observed differences by race warrant further investigation.

Validity of participant-reported diagnoses in an online patient registry: a report from the NF1 Patient Registry Initiative

BACKGROUND

With increased internet accessibility worldwide, it is now possible to assemble individuals with rare diseases through web-based patient registries. However, the validity of participant-reported medical diagnoses is unknown. The objective of this study was to evaluate the accuracy of participant-reported Neurofibromatosis Type 1 (NF1) diagnoses among participants in the NF1 Patient Registry Initiative (NPRI).

METHODS

Subjects enrolled in the NPRI from 5/17/2011 to 7/7/2014 were included. Medical records (MRs) were obtained for participants who returned medical record release forms (MRRFs) during the study period. Participants were classified as having definite, probable, suspected, or no NF1 diagnosis based on MR information. To assess whether a returned MRRF served as a reliable marker of MR-documented NF1, we calculated the positive predictive value (PPV) as the proportion of individuals with MR-documented NF1 among those from whom MRs were obtained. We further examined whether a returned MRRF predicted the number of reported NF1 clinical signs in multivariable linear regression analyses.

RESULTS

A total of 1456 individuals were included in the analyses. Of 416 individuals who returned MRRFs, 205 MRs were reviewed within the study period. The PPV ranged from 72.0 to 98.5% when including definite or definite/probable/suspected cases, respectively. The mean number of reported NF1 clinical signs was similar between those who returned (mean=3.3 ± 1.2) and did not return (mean=3.2 ± 1.3) their MRRFs. MRRF return was not a significant predictor of the number of NF1 clinical signs after adjusting for covariates.

CONCLUSION

These data strongly suggest that individuals enrolling in the NPRI accurately report their NF1 diagnosis.

Neurofibromatosis: chronological history and current issues

Neurofibromatosis, which was first described in 1882 by Von Recklinghausen, is a genetic disease characterized by a neuroectodermal abnormality and by clinical manifestations of systemic and progressive involvement which mainly affect the skin, nervous system, bones, eyes and possibly other organs. The disease may manifest in several ways and it can vary from individual to individual. Given the wealth of information about neurofibromatosis, we attempted to present this information in different ways. In the first part of this work, we present a chronological history, which describes the evolution of the disease since the early publications about the disorder until the conclusion of this work, focusing on relevant aspects which can be used by those wishing to investigate this disease. In the second part, we present an update on the various aspects that constitute this disease.

Intraorbital plexiform neurofibroma in an NF-1-negative patient

A 52-year-old patient presented with an orbital swelling and exophthalmos that enlarged over a period of about 40 years. The clinical examination showed massive exophthalmos and ptosis of the right eye without diplopia. The radiological investigation (MRI, CT and ultrasound) showed an unclear intraorbital mass with erosion of the orbital floor, infraorbital rim and orbital roof. The lesion was diagnosed histologically as a plexiform neurofibroma. The patient did not present any features of neurofibromatosis type 1 (NF-1) and molecular genetic analysis was unable to uncover a pathogenic sequence alteration in the NF-1 gene. Owing to the absence of clinical and ophthalmologic symptoms and the improbability of complete removal, the patient refused surgical intervention.

Neurofibromatosis type 1 (NF1): a protein truncation assay yielding identification of mutations in 73% of patients

Neurofibromatosis type 1 (NF1) is caused by mutations in a tumour suppressor gene located on chromosome 17 (17q11.2). Disease causing mutations are dispersed throughout the gene, which spans 350 kilobases and includes 59 exons. A common consequence of NF1 mutations is introduction of a premature stop codon, and the majority of mutant genes encode truncated forms of neurofibromin. We used a protein truncation assay to screen for mutations in 15 NF1 patients and obtained positive results in 11 of them (73%). Sequencing of cDNA and genomic DNA yielded identification of 10 different mutations, including four splicing errors, three small deletions, two nonsense mutations, and one small insertion. Nine mutations were predicted to cause premature termination of translation, while one mutation caused in frame deletion as a result ofexon skipping. In one other case involving abnormal splicing, five different aberrantly spliced transcripts were detected. One germline nonsense mutation (R1306X, 3916C>T) corresponded to the same base change that occurs by mRNA editing in normal subjects. The second nonsense mutation (R2496X) was the sole germline mutation that has been previously described. The subjects studied represented typically affected NF1 patients and no correlations between genotype and phenotype were apparent. A high incidence of ocular hypertelorism was observed.