Neurofibromatosis type 1: review of the first 200 patients in an Australian clinic

Mutation analysis and clinical profile of South African patients with Neurofibromatosis type 1 (NF1) phenotype

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic condition with complete age-dependent penetrance, variable expressivity and a global prevalence of ∼1/3,000. It is characteriszed by numerous café-au-lait macules, skin freckling in the inguinal or axillary regions, Lisch nodules of the iris, optic gliomas, neurofibromas, and tumour predisposition. The diagnostic testing strategy for NF1 includes testing for DNA single nucleotide variants (SNVs), copy number variants (CNVs) as well as RNA analysis for deep intronic and splice variants, which can cumulatively identify the causative variant in 95% of patients. In the present study, NF1 patients were screened using a next-generation sequencing (NGS) assay targeting NF1 exons and intron/exon boundaries for SNV and NF1 multiple ligation-dependent probe amplification (MLPA) analysis for CNV detection. Twenty-six unrelated Southern African patients clinically suspected of having NF1, based on the clinical diagnostic criteria developed by the National Institute of Health (NIH), were included in the current study. A detection rate of 58% (15/26) was obtained, with SNVs identified in 80% (12/15) using a targeted gene panel and NF1 gene deletion in 20% (3/15) identified using MLPA. Ten patients (38%) had no variants identified, although they met NF1 diagnostic criteria. One VUS was identified in this study in a patient that met NF1 diagnostic criteria, however there was no sufficient information to classify variant as pathogenic. The clinical features of Southern African patients with NF1 are similar to that of the known NF1 phenotype, with the exception of a lower frequency of plexiform neurofibromas and a higher frequency of developmental/intellectual disability compared to other cohorts. This is the first clinical and molecular characterisation of a Southern African ancestry NF1 cohort using both next-generation sequencing and MLPA analysis. A significant number of patients remained without a diagnosis following DNA-level testing. The current study offers a potential molecular testing strategy for our low resource environment that could benefit a significant proportion of patients who previously only received a clinical diagnosis without molecular confirmation.

Neurofibromatosis type1, type 2, tuberous sclerosis and Von Hippel-Lindau disease

Neurocutaneous syndromes (also known as phakomatoses) are heterogenous group of disorders that involve derivatives of the neuroectoderm. Each disease has diagnostic and pathognomonic criteria, once identified, thorough clinical examination to the patient and the family members should be done. Magnetic resonance imaging (MRI) is used to study the pathognomonic findings withing the CNS (Evans et al. in Am J Med Genet A 152A:327-332, 2010). This chapter includes the 4 most common syndromes faced by neurosurgeons and neurologists; neurofibromatosis types 1 and 2, tuberous sclerosis and Von Hippel-Lindau disease. Each syndrome has specific genetic anomaly that involves a tumor suppressor gene and the loss of inhibition of specific pathways. The result is a spectrum of cutaneous manifestations and neoplasms.

Head circumference and anthropometric changes and their relation to plexiform and skin neurofibromas in sporadic and familial neurofibromatosis 1 Brazilian adults: a cross-sectional study

Background

Neurofibromatosis 1 (NF1) is a common autosomal dominant syndrome with complete penetrance and highly variable expressivity. The cutaneous neurofibroma (Cnf) and plexiform neurofibroma (Pnf), café-au-lait spots, and freckle-like lesions are common in NF1, but many other manifestations can occur. We aimed to evaluate head circumference, height, weight, body mass index (BMI), head circumference-to-height ratio (HCHR) and waist–hip ratio (WHR) in adult NF1 Brazilian individuals versus a paired control group and investigate their correlation with the presence of clinically visible Pnfs, and number of “skin neurofibromas” (Snf), which include both cutaneous and subcutaneous neurofibromas.

Methods

A case–control study was conducted with 168 individuals, 84 with NF1 and 84 without NF1, paired by sex and age. Head circumference and anthropometric measurements, Snf quantification, evaluation of clinically visible Pnf and familial inheritance were accessed.

Results

Prevalence of macrocephaly was significantly higher in NF1 women. Height and weight were significantly lower in both males and females with NF1. HCHR was higher in the NF1 group than in the control group for both sexes. BMI was significantly lower in men with NF1. Waist and hip circumferences were significantly reduced in NF compared with the controls, but the mean WHR was significantly lower only in NF1 women. No correlation was found between the Snf and head circumference and anthropometric measurements, sex or family history. The presence and larger size of clinically visible plexiform neurofibromas were associated with normal stature (p = 0.037 and p = 0.003, respectively).

Conclusions

NF1 individuals have increased prevalence of macrocephaly, short stature, low BMI, and reduced abdominal fat. There is no relation between head circumference and anthropometric data with family history, or neurofibromas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02482-8.

Multidisciplinary neurocutaneous syndrome clinics: a systematic review and institutional experience

OBJECTIVE

Neurocutaneous syndromes have variable multisystem involvement. The multiorgan involvement, potential pathologies, and various treatment options necessitate collaboration and open discussion to ensure optimal treatment in any given patient. These disorders provide quintessential examples of chronic medical conditions that require a lifelong, multidisciplinary approach. The objectives of this study were to 1) perform a systematic review, thoroughly assessing different multidisciplinary clinic layouts utilized in centers worldwide; and 2) characterize an institutional experience with the management of these conditions, focusing on the patient demographics, clinical presentation, complications, and therapeutic strategies seen in a patient population.

METHODS

A systematic review of studies involving multidisciplinary clinics and their reported structure was performed according to PRISMA guidelines using the PubMed database. Then a retrospective chart review of patients enrolled in the Oklahoma Children’s Hospital Neurocutaneous Syndromes Clinic was conducted.

RESULTS

A search of the PubMed database yielded 251 unique results. Of these, 15 papers were included in the analysis, which identified 16 clinics that treated more than 2000 patients worldwide. The majority of these clinics treated patients with neurofibromatosis (13/16). The remaining clinics treated patients with von Hippel–Lindau syndrome (n = 1), tuberous sclerosis complex (n = 1), and multiple neurocutaneous syndromes (n = 1). The most commonly represented subspecialties in these clinics were genetics (15/16) and neurology (13/16). Five clinics (31%) solely saw pediatric patients, 10 clinics saw a combination of children and adults, and the final clinic had separate pediatric and adult clinics. The retrospective chart review of the Neurocutaneous Syndromes Clinic demonstrated that 164 patients were enrolled and seen in the clinic from April 2013 to December 2021. Diagnoses were made based on clinical findings or results of genetic testing; 115 (70%) had neurofibromatosis type 1, 9 (5.5%) had neurofibromatosis type 2, 35 (21%) had tuberous sclerosis complex, 2 (1%) had von Hippel–Lindau syndrome, 2 (1%) had Gorlin syndrome, and the remaining patient (0.6%) had Aarskog-Scott syndrome. Patient demographics, clinical presentation, complications, and therapeutic strategies are also discussed.

CONCLUSIONS

To the best of the authors’ knowledge, this is the first detailed description of a comprehensive pediatric neurocutaneous clinic in the US that serves patients with multiple syndromes. There is currently heterogeneity between described multidisciplinary clinic structures and practices. More detailed accounts of clinic compositions and practices along with patient data and outcomes are needed in order to establish the most comprehensive and efficient multidisciplinary approach for neurocutaneous syndromes.

Evaluation of Bone Mineral Density in Children Conceived via Assisted Reproductive Technology

OBJECTIVES

To investigate bone mineral density (BMD) differences between assisted reproductive technology (ART)-conceived children and naturally conceived (NC) children.

STUDY DESIGN

This retrospective cohort study included ART-conceived children and controls aged 1 to 12 years assessed with a follow-up protocol. Maternal and paternal background, birth condition, and growth and development indicators were analyzed.

RESULTS

The ART and NC groups exhibited differences in maternal and paternal childbearing age; maternal weight; maternal body mass index (BMI); maternal alcohol consumption; paternal smoking; delivery method; and serum zinc, iron, and lead levels. Multifactor analysis adjusted for relevant factors showed that paternal childbearing age and group significantly affected the BMD Z score. In the subgroup analysis, in vitro fertilization (IVF) (p=0.026) or intracytoplasmic sperm injection (ICSI) (p=0.008) had a positive impact on the BMD Z score. Male infertility only (p=0.010) or male infertility combined with polycystic ovary syndrome (PCOS) (p=0.026) may affect the BMD Z score. In the embryo transfer cycle subgroup analysis, compared with natural conception, both stimulation cycle fresh embryo transfer (p=0.019) and natural cycle frozen embryo transfer (p=0.006) had a positive effect on the BMD Z score.

CONCLUSIONS

The BMD levels of the ART and control groups were generally in the normal range. Paternal childbearing age and the use of ART independently affected the BMD Z score of the offspring.

Establishment of in-hospital clinical network for patients with neurofibromatosis type 1 in Nagoya University Hospital

Neurofibromatosis type 1 (NF1) is a genetic multisystem disorder. Clinicians must be aware of the diverse clinical features of this disorder in order to provide optimal care for it. We have set up an NF1 in-hospital medical care network of specialists regardless of patient age, launching a multidisciplinary approach to the disease for the first time in Japan. From January 2014 to December 2020, 246 patients were enrolled in the NF1 patient list and medical records. Mean age was 26.0 years ranging from 3 months to 80 years. The number of patients was higher as age at first visit was lower. There were 107 males (41%) and 139 females. After 2011, the number of patients has increased since the year when the medical care network was started. Regarding orthopedic signs, scoliosis was present in 60 cases (26%), and bone abnormalities in the upper arm, forearm, and tibia in 8 cases (3.5%). Neurofibromas other than cutaneous neurofibromas were present in 90 cases (39%), and MPNST in 17 cases (7.4%). We launched a multidisciplinary NF1 clinic system for the first time in Japan. For patients with NF1, which is a hereditary and systemic disease associated with a high incidence of malignant tumors, it will be of great benefit when the number of such clinics in Japan and the rest of Asia is increased.

Biallelic NF1 inactivation in high grade serous ovarian cancers from patients with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a multisystem disorder caused by germline heterozygous NF1 loss-of-function variants. The NF1 gene encodes neurofibromin, a RAS GTPase-activating protein, which functions by down-regulating RAS/RAF/MAPK-signalling pathways. Somatic NF1 aberrations frequently occur in sporadic ovarian cancer (OC), but the incidence of OC in NF1 patients is rare. Here we report the germline and somatic findings for two unrelated patients with NF1 and high-grade serous OC. Germline testing revealed a heterozygous NF1 pathogenic variant in each patient, c.7096_7101del (p.Asn2366_Phe2367del) and c.964delA (p.Ile322Leufs*54), respectively. No germline variants in well-established OC predisposition genes were detected, including BRCA1 and BRCA2. Tumor loss-of-heterozygosity analysis demonstrated loss of the wild type NF1 allele for both patients. Biallelic NF1 inactivation occurs as part of OC pathogenesis in NF1 patients. Although the penetrance of NF1-associated OC is insufficient to warrant risk-reducing interventions, our findings highlight the potential for therapies targeting the RAS/RAF/MAPK-signalling pathway for these cases.

Neurofibromatosis Type 1 with Severe Dystrophic Kyphosis: Surgical Treatment and Prognostic Analysis of 27 Patients

OBJECTIVE

The aim of the present study was to explore the surgical treatment and prognosis of 27 cases of neurofibromatosis type 1 with severe dystrophic kyphosis.

METHODS

We performed surgical treatment for scoliosis and kyphosis caused by dystrophic curves at Peking Union Medical College Hospital, Beijing, China from December 2015 to December 2017. The study included 21 patients with moderate to severe kyphosis, 12 males and 9 females, with an average age of 14.95 ± 6.05 years. All patients had kyphosis angles greater than 70° and had more than four skeletal developmental defects. A total of 6 patients with severe kyphosis, 2 males and 4 females, with an average age of 12.5 years, had more than five skeletal developmental defects with a kyphosis angle greater than 90° or a lumbar kyphosis angle greater than 40°. According to the patient's own situation, we adopted a low-grade surgery scheme (grades 1 or 2) or a high-grade surgery scheme (grades 3-6). The low-grade surgery was mainly lower articular surface resection or pontodestomy, and the high-grade surgery was mainly apical vertebral body or upper discectomy. All patients were followed up to determine their prognosis.

RESULTS

Statistical analysis showed that there was a significant difference in preoperative and postoperative scores between the two groups (P < 0.05), and scoliosis correction showed that surgical treatment had a significant effect on scoliosis kyphosis. The mean follow-up time was 66.7 months. Follow-up results showed that 50% of complications after internal fixation were related to high-level surgery. Complications included displacement of the titanium cage, removal of the lamina hook, formation of pseudoarthrosis, and internal fixation failure (with a rate of 7.7%-14.3%). In contrast, there were no associated symptoms for low-grade surgery. In addition, the results showed that gender, age, extent of resection, height, and body mass index had no significant effect on preoperative, postoperative, and prognostic indicators of patients (P > 0.05).

CONCLUSION

Early identification of dysplastic scoliosis-related deformities plays an important role in surgical planning and prognosis, and low-level surgical procedures are more favorable for patients' prognosis.

Café au lait spots: When and how to pursue their genetic origins

Café au lait spots are common birthmarks seen sporadically and in association with several genetic syndromes. Dermatologists are often asked to evaluate these birthmarks both by other physicians and by parents. In some cases, it is challenging to know when and how to pursue further evaluation. Diagnostic challenges may come in the form of the appearance of the individual lesions, areas and patterns of cutaneous involvement, and associated features (or lack thereof). In this review, we aim to clarify when and how to evaluate the child with multiple or patterned café au lait spots and to explain some emerging concepts in our understanding of the genetics of these lesions.

A comparison of neuropsychological function between monozygotic twins with neurofibromatosis, type 1: A case report

Objective: Neurofibromatosis type 1 (NF-1) is an autosomal dominant genetic disorder that commonly presents with cognitive impairment and greater rates of learning disorders and academic difficulty compared to the general population. Investigations of neurological and physiological expression of NF-1 in monozygotic twins identified intrapair similarities and differences. Monozygotic twins with NF-1 have been found to have similar IQ scores as well as concordant diagnoses of attention-deficit/hyperactivity disorder and learning disabilities. There have been no previous reports on similarities and differences in neuropsychological profiles between monozygotic twins with NF-1. The purpose of this article is to examine the results of comprehensive neuropsychological evaluations for a pair of monozygotic twins with NF-1.Method: A pair of 19-year-old female, African-American monozygotic twins with NF-1 underwent neuropsychological evaluations in an outpatient clinic. Findings are reported following the CAse REport (CARE) guidelines.Results: The twins demonstrated similar impairment in processing speed, working memory, and attention span; however, differences also were found.Conclusions: Intrapair similarities and differences on neuropsychological assessment were found between monozygotic twins with NF-1. Primary deficits were suggestive of a frontal-subcortical pattern and could be consistent with remote neuroimaging. When differences did occur, performance was typically better for Twin A, who had also showed greater improvement on neuroimaging. Implications and directions for future research are discussed. Specifically, this case demonstrates the need for inclusion of neuropsychological assessment in studies of larger cohorts of monozygotic twins with NF-1 and correlation of neuropsychological findings with neuroimaging and postzygotic mutations.

A novel NF1 frame-shift mutation c.703_704delTA in a Chinese pedigree with neurofibromatosis type 1

We analyzed the clinical features and NF1 gene mutation in a Chinese pedigree of neurofibromatosis type 1 (NF1). Three members of this family were NF1 patients presenting with different clinical phenotypes and the others were asymptomatic. Exons of NF1 were amplified by polymerase chain reaction, sequenced, compared with a reference database. One novel NF1 frame-shift mutation c.703_704delTA, which resulted in a premature stop signal at codon 720 and the synthesis of truncated, was revealed. This mutation segregated with the NF1 members is likely responsible for the pathogenesis of NF1 in the family.

Macrocephaly: Solving the Diagnostic Dilemma

Macrocephaly is a relatively common clinical condition affecting up to 5% of the pediatric population. It is defined as an abnormally large head with an occipitofrontal circumference greater than 2 standard deviations above the mean for a given age and sex. Megalencephaly refers exclusively to brain overgrowth exceeding twice the standard deviation. Macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, whereas megalencephaly is more often syndromic. Megalencephaly can be divided into 2 subtypes: metabolic and developmental, caused by genetic defects in cellular metabolism and alterations in signaling pathways, respectively. Neuroimaging plays an important role in the evaluation of macrocephaly, especially in the metabolic subtype which may not be overtly apparent clinically. This article outlines the diverse etiologies of macrocephaly, delineates their clinical and radiographic features, and suggests a clinicoradiological algorithm for evaluation.

Parental age and risk of genetic syndromes predisposing to nervous system tumors: nested case-control study

Purpose

Phacomatoses are genetic syndromes that are associated with increased risk of developing nervous system tumors. Phacomatoses are usually inherited, but many develop de novo, with unknown etiology. In this population-based study, we investigated the effect of parental age on the risk of phacomatoses in offspring.

Patients and methods

The study was a population-based nested case–control study. All individuals born and residing in Sweden between January 1960 and December 2010 were eligible for inclusion. Using the Patient Register, 4625 phacomatosis cases were identified and further classified as familial or nonfamilial. Ten matched controls per case were randomly selected from the eligible population. Data were analyzed using conditional logistic regression. Analyses were conducted for neurofibromatosis alone (n=2089) and other phacomatoses combined (n=2536).

Results

Compared with offspring of fathers aged 25–29 years, increased risk estimates of nonfamilial neurofibromatosis were found for offspring of fathers aged 35–39 years (odds ratio [OR]=1.43 [95% CI 1.16–1.74]) and ≥40 years (OR =1.74 [95% CI 1.38–2.19]). For other nonfamilial phacomatoses, the risk estimate for offspring of fathers aged ≥40 years was OR =1.23 (95% CI 1.01–1.50). Paternal age was not associated with familial phacomatoses, and no consistent association was observed with maternal age.

Conclusion

The findings show a consistent increase in risk of de novo occurrence of phacomatoses predisposing to nervous system tumors in offspring with increasing paternal age, most pronounced for neurofibromatosis, while maternal age did not seem to influence the risk. These findings suggest an increasing rate of new mutations in the NF1 and NF2 genes in spermatozoa of older fathers.

Paediatric neurological examination

Children with either normal or impaired cognitive abilities presenting to child and adolescent mental health services (CAMHS) with psychiatric or behavioural problems may have an underlying syndromic or neurological diagnosis. Diagnostic clues exist in the measurement of growth and head circumference, recognition of dysmorphism and in the full physical and, in particular, neurological examination of the individual. Recognition of these clues will allow referral, as necessary, for further investigation or surveillance. Prompt diagnosis of disorders is important for many reasons: the provision of an explanation for the child's current difficulties and the anticipation of further difficulties; the recognition of genetic, and therefore reproductive, implications for parents and siblings; the recognition of a grim prognosis; and access to any available treatments.

Ophthalmic manifestations in neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a relatively common multisystemic inherited disease and has been extensively studied by multiple disciplines. Although genetic testing and confirmation are available, NF1 remains a clinical diagnosis. Many manifestations of NF1 involve the eye and orbit, and the ophthalmologist, therefore, plays a significant role in the diagnosis and treatment of NF1 patients. Improvements in diagnostic and imaging instruments have provided new insight to study the ophthalmic manifestations of the disease. We provide a comprehensive and up-to-date overview of the ocular and orbital manifestations of NF1.

No. 346-Advanced Reproductive Age and Fertility

OBJECTIVE

To improve awareness of the natural age-related decline in female and male fertility with respect to natural fertility and assisted reproductive technologies (ART), provide recommendations for their management, and to review investigations in the assessment of ovarian aging.

OPTIONS

This guideline reviews options for the assessment of ovarian reserve and fertility treatments using ART with women of advanced reproductive age presenting with infertility.

OUTCOMES

The outcomes measured are the predictive value of ovarian reserve testing and pregnancy rates with natural and assisted fertility.

EVIDENCE

Published literature was retrieved through searches of PubMed or Medline, CINAHL, and The Cochrane Library in June 2010, using appropriate key words ("ovarian aging," "ovarian reserve," "advanced maternal age," "advanced paternal age," and "assisted reproductive technology"). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated into the guideline to December 2010.

VALUES

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice were ranked according to the method described in that report.

BENEFITS, HARMS, AND COSTS

Primary and specialist health care providers and women will be better informed about ovarian aging and the age-related decline in natural fertility and about options for ART.

RECOMMENDATIONS

Pedicle screw versus hybrid posterior instrumentation for dystrophic neurofibromatosis scoliosis

Surgical management of severe rigid dystrophic neurofibromatosis (NF) scoliosis is technically demanding and produces varying results. In the current study, we reviewed 9 patients who were treated with combined anterior and posterior fusion using different types of instrumentation (i.e., pedicle screw, hybrid, and all-hook constructs) at our institute.Between September 2001 and July 2010 at our institute, 9 patients received anterior release/fusion and posterior fusion with different types of instrumentation, including a pedicle screw construct (n = 5), a hybrid construct (n = 3), and an all-hook construct (n = 1). We compared the pedicle screw group with the hybrid group to analyze differences in preoperative curve angle, immediate postoperative curve reduction, and latest follow-up curve angle.The mean follow-up period was 9.5 ± 2.9 years. The average age at surgery was 10.3 ± 3.9 years. The average preoperative scoliosis curve was 61.3 ± 13.8°, and the average preoperative kyphosis curve was 39.8 ± 19.7°. The average postoperative scoliosis and kyphosis curves were 29.7 ± 10.7° and 21.0 ± 13.5°, respectively. The most recent follow-up scoliosis and kyphosis curves were 43.4 ± 17.3° and 29.4 ± 18.9°, respectively. There was no significant difference in the correction angle (either coronal or sagittal), and there was no significant difference in the loss of sagittal correction between the pedicle screw construct group and the hybrid construct group. However, the patients who received pedicle screw constructs had significantly less loss of coronal correction (P < .05). Two patients with posterior instrumentation, one with an all-hook construct and the other with a hybrid construct, required surgical revision because of progression of deformity.It is difficult to intraoperatively correct dystrophic deformity and to maintain this correction after surgery. Combined anterior release/fusion and posterior fusion using either a pedicle screw construct or a hybrid construct provide similar curve corrections both sagittally and coronally. After long-term follow-up, sagittal correction was maintained with both constructs. However, patients treated with posterior instrumentation using pedicle screw constructs had significantly less loss of coronal correction.

N o 346-Âge génésique avancé et fertilité

OBJECTIFS

Sensibiliser la population à la baisse naturelle de la fertilité avec l'âge, chez les femmes et les hommes, et à l'égard de la reproduction naturelle et des technologies de procréation assistée (TPA); formuler des recommandations de prise en charge; et analyser les méthodes d'évaluation du vieillissement ovarien.

OPTIONS

La présente directive clinique passe en revue les options offertes pour l'évaluation de la réserve ovarienne et pour le traitement de l'infertilité faisant appel aux TPA chez les femmes d'âge génésique avancé infertiles.

ISSUES

Les issues mesurées sont les valeurs prédictives de l'évaluation de la réserve ovarienne et les taux de grossesse découlant de la fertilité naturelle et de la fertilité assistée. DONNéES: Nous avons examiné des études publiées récupérées au moyen de recherches dans PubMed, Medline, CINAHL et la Bibliothèque Cochrane en juin 2010 à l'aide de mots-clés appropriés (ovarian aging, ovarian reserve, advanced maternal age, advanced paternal age, et assisted reproductive technology). Nous n'avons tenu compte que des résultats provenant de revues systématiques, d'essais cliniques, randomisés ou non, et d'études observationnelles. Aucune restriction de date ou de langue n'a été employée. Les recherches ont été refaites régulièrement, et les résultats ont été incorporés à la directive clinique jusqu'en décembre 2010.

VALEURS

La qualité des données a été évaluée au moyen des critères énoncés dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs. Les recommandations quant à la pratique ont été classées conformément à la méthode décrite dans ce rapport. AVANTAGES, DéSAVANTAGES ET COûTS: Les patientes et les fournisseurs de soins primaires et spécialisés seront mieux renseignés sur le vieillissement ovarien, la baisse de la fertilité naturelle liée à l'âge et les TPA.

RECOMMENDATIONS

Predicting neurofibromatosis type 1 risk among children with isolated café-au-lait macules

BACKGROUND

Although isolated cafe-au-lait macules (CALMs) are a common skin finding, they are an early feature of neurofibromatosis type 1 (NF1).

OBJECTIVE

We sought to develop an algorithm determining the risk of children with CALMs to have constitutional NF1.

METHODS

We conducted a retrospective study of patients with isolated CALMs. Diagnosis of NF1 was based on detecting NF1 mutation in blood or fulfilling clinical criteria.

RESULTS

In all, 170 of 419 (41%) and 21 of 86 (24%) children with isolated CALMs who underwent molecular testing and clinical follow-up, respectively, were given a diagnosis of NF1. Presence of fewer than 6 CALMs at presentation or atypical CALMs was associated with not having NF1 (P < .001). An algorithm based on age, CALMs number, and presence of atypical macules predicted NF1 in both cohorts. According to the algorithm, children older than 29 months with at least 1 atypical CALM or less than 6 CALMs have a 0.9% (95% confidence interval 0%-2.6%) risk for constitutional NF1 whereas children younger than 29 months with 6 or more CALMs have a high risk (80.4%, 95% confidence interval 74.6%-86.2%).

LIMITATIONS

The study was designed to detect constitutional NF1 and not NF1 in mosaic form.

CONCLUSIONS

A simple algorithm enables categorization of children with isolated CALMs as being at low or high risk for having NF1.

Emerging genotype-phenotype relationships in patients with large NF1 deletions

The most frequent recurring mutations in neurofibromatosis type 1 (NF1) are large deletions encompassing the NF1 gene and its flanking regions (NF1 microdeletions). The majority of these deletions encompass 1.4-Mb and are associated with the loss of 14 protein-coding genes and four microRNA genes. Patients with germline type-1 NF1 microdeletions frequently exhibit dysmorphic facial features, overgrowth/tall-for-age stature, significant delay in cognitive development, large hands and feet, hyperflexibility of joints and muscular hypotonia. Such patients also display significantly more cardiovascular anomalies as compared with patients without large deletions and often exhibit increased numbers of subcutaneous, plexiform and spinal neurofibromas as compared with the general NF1 population. Further, an extremely high burden of internal neurofibromas, characterised by >3000 ml tumour volume, is encountered significantly, more frequently, in non-mosaic NF1 microdeletion patients than in NF1 patients lacking such deletions. NF1 microdeletion patients also have an increased risk of malignant peripheral nerve sheath tumours (MPNSTs); their lifetime MPNST risk is 16–26%, rather higher than that of NF1 patients with intragenic NF1 mutations (8–13%). NF1 microdeletion patients, therefore, represent a high-risk group for the development of MPNSTs, tumours which are very aggressive and difficult to treat. Co-deletion of the SUZ12 gene in addition to NF1 further increases the MPNST risk in NF1 microdeletion patients. Here, we summarise current knowledge about genotype–phenotype relationships in NF1 microdeletion patients and discuss the potential role of the genes located within the NF1 microdeletion interval whose haploinsufficiency may contribute to the more severe clinical phenotype.

Neurofibromatosis Clinic: A Report on Patient Demographics and Evaluation of the Clinic

BACKGROUND

Neurofibromatosis type 1 (NF1) is a common single-gene disorder. A multidisciplinary approach to the management of NF1 patients is necessitated by the heterogeneity of clinical manifestations. Although multidisciplinary paediatric clinics have been well established, there is a dearth of such resources for adults with NF1. Herein we report our one-year institutional experience with a multidisciplinary adult NF1 clinic.

METHODS

A multidisciplinary team was assembled, and an NF Patient Registry Initiative questionnaire was adapted to collect patient-reported data during clinics. Multiple databases were searched to identify publications pertaining to the experience of other multidisciplinary NF1 clinics focusing on adult patients. Data on patient epidemiology and clinical staff were compared to our data.

RESULTS

A total of 77 patients were scheduled, and 68 attended the clinic, of whom 66 completed the intake questionnaire. The demographic and clinical data from this Canadian population are mostly consistent with previous reports, with some exceptions. Clinical data related to immune system involvement such as asthma, airway/breathing-related difficulties or allergies were striking in our NF1 population. Six relevant published reports of other NF1 clinics were identified. Reports from these studies pertained to periods ranging from 10 to 38 months, and the number of adults assessed ranged from 19 to 177 patients.

CONCLUSIONS

The structure of our clinic and the patient volume are comparable to those of other established centres found in the literature. Our data offer valuable cross-sectional prevalence statistics in the Canadian population. The patient-reported data concerning involvement of the immune system contribute to an emerging recognized medical concern within the NF1 population and warrant further clinical and basic investigation.

The effect of parental age on the presence of de novo mutations - Lessons from neurofibromatosis type I

Background

Neurofibromatosis type 1 (NF1) is the most common autosomal dominant neurocutaneous disease with a prevalence of 1:2500. Approximately, 50% of the cases are sporadic. Advanced paternal age is associated with germline mutations and autosomal diseases. We aimed to use NF1 as a paradigm to study the effect of parental age on sporadic mutation rates for both advanced and younger parental ages.

Methods

The medical charts of 118 NF1 pediatric patients followed in a specialized Israeli NF1 clinic were evaluated. Thirty‐one cases were diagnosed by genetic tests and 87 by NIH clinical criteria. Sixty‐four cases (54%) had a negative family history of NF1 (sporadic cases). Data on parental ages at the time of the children's birth were compared to the national population database.

Results

Parental age of children with sporadic NF1 was higher than the general population (32.7 years vs. 30.1 years, respectively, for the mothers and 36.5 years vs. 32.6 years, respectively, for the fathers; P < 0.0001 for both groups). In contrast, the age of the mothers and the fathers in the familial cases (30.3 and 33.9 years, respectively) did not differ from the general population. Significantly, fewer fathers of the sporadic group had been 25–29 years old at their child's birth compared with fathers in the general population (7.8% vs. 21%, respectively, P = 0.009), and significantly more fathers were ≥40 years old (29.7% vs. 13.6%, respectively, P = 0.0002). Differences in maternal age between these two groups were less prominent.

Conclusion

Parents of sporadic NF1 cases are older. The risk for sporadic NF1 was lower when the fathers were younger at the time of the affected child's birth, and gradually increased with paternal age.

Adaptive behavior in young children with neurofibromatosis type 1

Neurofibromatosis-1 is the most common single gene disorder affecting 1 in 3000. In children, it is associated not only with physical features but also with attention and learning problems. Research has identified a downward shift in intellectual functioning as well, but to date, there are no published studies about the everyday adaptive behavior of children with NF1. In this study, parental reports of adaptive behavior of 61 children with NF1 ages 3 through 8 were compared to an unaffected contrast group (n = 55) that comprised siblings and community members. Significant group differences in adaptive skills were evident and were largely related to group differences in intellectual functioning. In a subsample of children with average-range intellectual functioning, group differences in parent-reported motor skills were apparent even after controlling statistically for group differences in intellectual functioning. The implications of the findings for the care of children with NF1 are discussed.

Optic nerve glioma treatment with fractionated stereotactic radiotherapy

In the current report, the authors present a case of optic nerve glioma treated with fractionated stereotactic radiotherapy (FSRT). An 11-year-old girl was referred to our clinic with increasing proptosis over a 1-year period. At that time orbital MRI revealed a 20 × 17-mm mass in the right retroorbital lipomatous tissue, and FSRT was delivered to the tumor using the CyberKnife. During the 1.5-year follow-up, ophthalmological examinations did not indicate any treatment-related severe toxicity, and posttreatment MRI demonstrated marked regression of the lesion to 13 × 10 mm. Given the scarcity of reports on this subject, the authors support more extended studies of the CyberKnife for the effective treatment of this relatively common childhood tumor.

Malignant pheochromocytoma in neurofibromatosis; mutation screening of RET proto-oncogene, VHL and SDH gene

AIM: To investigate pathogenic mutations related to malignant pheochromocytoma in neurofibromatosis (NF).

METHODS: We present a patient with NF and metastatic pheochromocytoma in whom genetic screening for presence of pathogenic mutations in RET proto-oncogene, von Hippel-Lindau (VHL) and succinate dehydrogenase complex subunits B (SDHB) genes were investigated. RET proto-oncogene mutation screening for exons 10, 11, 13, 14, 15, 16 were examined by polymerase chain reaction (PCR) and direct DNA sequencing in patient. Mutation screening for exons 1, 2, 3 of VHL gene was carried out. Both forward and reverse strands were subjected to direct sequencing after PCR amplification. The entire coding sequence of SDHB gene was screened for the presence of pathogenic mutations by PCR-sequencing.

RESULTS: A 45-year-old man presented with abdominal pain and hypertension over the previous year. The patient was a known case of neurofibromatosis type 1 (NF1) who presented at the age of 15 years with hyperpigmented and hypopigmented lesions. After complete evaluation for hypertension, biochemical tests and imagings indicated a malignant pheochromocytoma of 120 mm × 70 mm in size. The patient underwent left adrenalectomy, nephrectomy and splenectomy. After surgery the symptoms improved and blood pressure was controlled. After 5 years he was admitted again for evaluation of hypertensive crisis. Biochemical tests were again consistent with pheochromocytoma and disease relapse. Imaging studies and liver biopsy confirmed metastatic pheochromocytoma to the liver and para-aortic area. 131 Iodine-metaiodobenzylguanidine therapy was carried out. Genetic screening of VHL (exons 1, 2, 3), RET proto-oncogene (exons 10, 11, 13, 14, 15, 16) and SDH complex subunits revealed no pathogenic mutation.

CONCLUSION: We conclude that mutations in the NF1 gene are responsible for the patient’s clinical findings. However, would be helpful to further examine somatic mutations for a more precise study of genotype-phenotype correlation.

Posterior vertebral column resection for the treatment of dystrophic kyphosis associated with type-1 neurofibromatosis: a case report and review of the literature

STUDY DESIGN

Case report.

OBJECTIVE

To describe the use of posterior-only vertebral column resection and postoperative traction for spinal deformity associated with type-1 neurofibromatosis (NF1).

SUMMARY OF BACKGROUND DATA

Vertebral deformity, namely, thoracic scoliosis, is the predominant orthopedic manifestation of NF1. Patients may present with debilitating pain and rarely, myelopathy. The commonly dystrophic nature of these deformities makes them particularly recalcitrant to surgical correction. Traditionally, circumferential arthrodesis via combined anterior and posterior approaches has been recommended.

METHODS

Clinical and radiographical case review.

RESULTS

A 14-year-old adolescent boy with NF1, severe cervicothoracic angular kyphosis, thoracic dislocation, and myelopathy presented status postmultiple anterior and posterior spinal fusions. The patient underwent posterior-only vertebral column resection after 6 weeks of halo-gravity traction. The surgery consisted of thoracic laminectomies, total corpectomies of T3 and T4, circumferential fusion, and posterior instrumentation from the occiput to T11. Autologous rib and iliac crest grafts were used as fusion substrate. Postoperatively, a halo vest was worn for 4 months to support the correction of his chin-on-chest deformity. The patient's neurological status returned to normal by 6 weeks postoperatively, and solid fusion was radiologically evident after 1 year.

CONCLUSION

We think that posterior-only vertebral column resection represents a safe and efficacious but technically challenging option for the treatment of angular kyphotic spinal deformity and associated neurological deficit in patients with NF1.

Quantitative assessment of whole-body tumor burden in adult patients with neurofibromatosis

PURPOSE

Patients with neurofibromatosis 1 (NF1), NF2, and schwannomatosis are at risk for multiple nerve sheath tumors and premature mortality. Traditional magnetic resonance imaging (MRI) has limited ability to assess disease burden accurately. The aim of this study was to establish an international cohort of patients with quantified whole-body internal tumor burden and to correlate tumor burden with clinical features of disease.

METHODS

We determined the number, volume, and distribution of internal nerve sheath tumors in patients using whole-body MRI (WBMRI) and three-dimensional computerized volumetry. We quantified the distribution of tumor volume across body regions and used unsupervised cluster analysis to group patients based on tumor distribution. We correlated the presence and volume of internal tumors with disease-related and demographic factors.

RESULTS

WBMRI identified 1286 tumors in 145/247 patients (59%). Schwannomatosis patients had the highest prevalence of tumors (P = 0.03), but NF1 patients had the highest median tumor volume (P = 0.02). Tumor volume was unevenly distributed across body regions with overrepresentation of the head/neck and pelvis. Risk factors for internal nerve sheath tumors included decreasing numbers of café-au-lait macules in NF1 patients (P = 0.003) and history of skeletal abnormalities in NF2 patients (P = 0.09). Risk factors for higher tumor volume included female gender (P = 0.05) and increasing subcutaneous neurofibromas (P = 0.03) in NF1 patients, absence of cutaneous schwannomas in NF2 patients (P = 0.06), and increasing age in schwannomatosis patients (p = 0.10).

CONCLUSION

WBMRI provides a comprehensive phenotype of neurofibromatosis patients, identifies distinct anatomic subgroups, and provides the basis for investigating molecular biomarkers that correlate with unique disease manifestations.

Articulation in schoolchildren and adults with neurofibromatosis type 1

Several authors mentioned the occurrence of articulation problems in the neurofibromatosis type 1 (NF1) population. However, few studies have undertaken a detailed analysis of the articulation skills of NF1 patients, especially in schoolchildren and adults. Therefore, the aim of the present study was to examine in depth the articulation skills of NF1 schoolchildren and adults, both phonetically and phonologically. Speech samples were collected from 43 Flemish NF1 patients (14 children and 29 adults), ranging in age between 7 and 53 years, using a standardized speech test in which all Flemish single speech sounds and most clusters occur in all their permissible syllable positions. Analyses concentrated on consonants only and included a phonetic inventory, a phonetic, and a phonological analysis. It was shown that phonetic inventories were incomplete in 16.28% (7/43) of participants, in which totally correct realizations of the sibilants /ʃ/ and/or /ʒ/ were missing. Phonetic analysis revealed that distortions were the predominant phonetic error type. Sigmatismus stridens, multiple ad- or interdentality, and, in children, rhotacismus non vibrans were frequently observed. From a phonological perspective, the most common error types were substitution and syllable structure errors. Particularly, devoicing, cluster simplification, and, in children, deletion of the final consonant of words were perceived. Further, it was demonstrated that significantly more men than women presented with an incomplete phonetic inventory, and that girls tended to display more articulation errors than boys. Additionally, children exhibited significantly more articulation errors than adults, suggesting that although the articulation skills of NF1 patients evolve positively with age, articulation problems do not resolve completely from childhood to adulthood. As such, the articulation errors made by NF1 adults may be regarded as residual articulation disorders. It can be concluded that the speech of NF1 patients is characterized by mild articulation disorders at an age where this is no longer expected.

LEARNING OUTCOMES

Readers will be able to describe neurofibromatosis type 1 (NF1) and explain the articulation errors displayed by schoolchildren and adults with this genetic syndrome.

Neurocutaneous syndrome: a prospective study

BACKGROUND

Neurocutaneous syndromes (NCS) are a group of genetic disorders that produce a variety of developmental abnormalities of the skin along with an increased risk of neurological complications. Cutaneous manifestations usually appear early in life and progress with time, but neurological features generally present at a later age. There is a paucity of data regarding the evolution of skin lesions and their correlation with the central nervous system involvement in children.

AIM

The primary objective was to track the course of skin lesions in various forms of NCS in the pediatric age group. Our secondary aim was to assess whether there was any predictive value of the lesions in relation to the neurological manifestations.

MATERIALS AND METHODS

This prospective longitudinal study was conducted at a tertiary care pediatric dermatology referral clinic of the Institute of Child Health, Kolkata, West Bengal. Children between the age group 0 and 12 years were included in the study on the basis of standard diagnostic criteria for different NCS, during the period from March, 2000 to February, 2004, and each of the enrolled cases were followed up for a duration of six years.

RESULTS

The study population comprised of 67 children (35 boys, 32 girls).The mean age of presentation was 33.8±27.8 months (range 10 days to 111 months). The various forms of NCS observed was neurofibromatosis 1(NF1) (n=33), tuberous sclerosis complex (TSC) (n=23), Sturge Weber syndrome (n=6), ataxia telangiectasia (n=2), PHACE syndrome (n=1), incontinentia pigmenti (n=1), and hypomelanosis of Ito (n=1). The presentations were varied, ranging from predominantly cutaneous to primarily neurological, depending on the disease entity and age group concerned. There was a significant increase in the number of café au lait macules (CALMs) with time (P=0.0002) in NF1, unlike that of hypopigmented macules of TSC (P=0.15). Statistically, no relation was documented between the evolution of skin lesions and neurological manifestations in the major groups.

CONCLUSION

As NCS is not an uncommon disease in children, it is always necessary to find out the subtle neurological signs, whenever we observe any case with cutaneous markers suggestive of NCS. In addition, it is a must to do a detailed dermatological examination in a child with central nervous system involvement, in the pediatric population. However, the neurological course cannot be predicted from skin lesions.

Objective assessment of nasality in Flemish adults with neurofibromatosis type 1

When characterizing the speech of a patient with neurofibromatosis type 1 (NF1), hypernasality is often mentioned. As few studies applied technically assisted evaluations of nasality in NF1 patients, the aim of the present study was to document the nasal resonance of adults with NF1 using nasometry. The nasometric data obtained from the NF1 patients were compared with the nasalance scores of a healthy control group and with normative data. The final study group consisted of 24 adult NF1 patients and 16 controls, all living in the East Flemish part of Belgium. Nasalance scores were obtained while the participants sustained three vowels (/a:/, /i./, and /u./) and one consonant (/m/) and read three standard nasalance passages. Despite the inter- and intra-subject variability, we observed that NF1 patients as a group exhibited higher mean nasalance scores than controls. This finding was especially clear in males. Potential genotype-phenotype correlations between NF1 mutation type and hypernasality were examined but could not be demonstrated. Conversely, comparison of the nasometric data obtained from the NF1 patients with magnetic resonance imaging findings showed some degree of interesting correlation. We conclude that, notwithstanding the small sample size for some analyses, nasality is an area of interest in the NF1 population. As altered nasality influences speech intelligibility, nasality requires attention during follow-up visits, particularly when it concerns a male NF1 patient.

Voice-related quality of life in adults with neurofibromatosis type 1

OBJECTIVE

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder, which occurs in about one in 3000-4000 people. Its hallmark features include multiple café-au-lait spots and neurofibromas. Voice characteristics of NF1 patients have been documented using both subjective and objective evaluations. However, the relative impact of these voice characteristics on daily activities has, as far as we know, not been examined yet.

METHODS

Thirty adults with NF1 were asked to complete the Flemish Dutch version of the Voice Handicap Index (VHI). Additionally, the level of severity of NF1 was rated and Dysphonia Severity Indices (DSIs) were collected. The results of the patient group were compared with those of a healthy control group frequency matched for age, gender, smoking behavior, and vocal usage.

RESULTS

NF1 patients obtained significantly higher VHI scores compared with healthy controls. Differences between the patient and control group were especially marked for daily functioning and affective responses. Men and women with NF1 had similar VHI scores, but total VHI score did increase with age. An apparent association between VHI, DSI, and severity of NF1 could not be demonstrated.

CONCLUSION

It is likely that the elevated VHI scores observed in the patient group were not merely caused by the voice characteristics associated with NF1. A flow over from other psychophysical issues relating to the disease might have played a role.

Pilot study of a novel computerized task to assess spatial learning in children and adolescents with neurofibromatosis type 1

Difficulties with visual-spatial learning are frequently observed and often considered to be the hallmark of neurocognitive impairment in neurofibromatosis type 1. The computerized Arena Maze is a virtual environment task that has been developed as a human paradigm to the Morris Water Maze, which is used to evaluate spatial learning in animal models. The authors evaluated this task as a measure of spatial learning in children with neurofibromatosis type 1 compared with their unaffected siblings. Affected children were able to learn the task and navigate the virtual environment; however, they performed more poorly on standard measures of spatial learning and spatial working memory than their siblings. The group with neurofibromatosis type 1 demonstrated decreased proficiency in earlier target trials and had more difficulty in remembering target location. This study demonstrates the potential utility of a novel virtual task to assess spatial learning deficits in children with neurofibromatosis type 1.

Neurofibromatosis type 1 in genetic counseling practice: recommendations of the National Society of Genetic Counselors

The objective of this document is to provide recommendations for the genetic counseling of patients and families undergoing evaluation for neurofibromatosis type 1 (NF1) or who have received a diagnosis of NF1. These recommendations are the opinions of a multi-center working group of genetic counselors with expertise in the care of individuals with NF1. These recommendations are based on the committee's clinical experiences, a review of pertinent English language medical articles, and reports of expert committees. These recommendations are not intended to dictate an exclusive course of management, nor does the use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of an individual patient.

Electrosurgical excision technique for the treatment of multiple cutaneous lesions in neurofibromatosis type I

Neurofibromatosis I (NF1) is an autosomal dominant disease that presents with multiple cutaneous lesions often numbering into the 500-1000 range. In addition to the psychosocial implications, there are limited surgical options for this condition. A series of 97 consecutive patients with NF1 presented with numerous cutaneous lesions. Treatment involved electrocautery excision of the lesions using a handheld device in one or more stages. This technique resulted in the removal of large numbers of lesions in limited stages, with minimal scarring, minor discomfort and high patient acceptance. For patients with NF1, single or multistage excision of cutaneous lesions using electrocautery produces an acceptable aesthetic result with high patient satisfaction.

Retrospective analysis of patients attending a neurofibromatosis type 1 clinic

AIM

To undertake a retrospective analysis of the patients who attended the neurofibromatosis type 1 clinic (NF clinic) at the Royal Children's Hospital, Melbourne between March 2001 and May 2004. From this analysis, we aimed to ascertain the frequency and nature of complications of NF1 in this cohort and compare this with other large series.

METHODS

Genetic files and hospital records of patients who attended the NF clinic were reviewed. Data regarding the clinical features and NF1-related complications present in the patient population were entered into a database and then analysed.

RESULTS

Data were available for 121 patients with presumed or confirmed diagnoses of NF1 who attended the NF clinic between the study dates. While most patients were referred to the clinic for 'routine surveillance', complications of NF1 were common. Forty-four per cent of patients had learning difficulties, 21% had optic gliomas and 17% had plexiform neurofibromas. Fifty-five per cent of those with plexiform neurofibromas required at least one surgical procedure.

CONCLUSION

The NF clinic was accessed by patients of all ages to assist with diagnosis, provide routine surveillance and manage complex complications of NF1. The prevalence and range of complications of NF1 of the patients attending this clinic is similar to other large retrospective studies in tertiary centres.

Optic gliomas of the anterior visual pathway

PURPOSE OF REVIEW

To review advances in the diagnosis and management of optic-pathway gliomas made within the past 5 years.

RECENT FINDINGS

Important papers regarding optic-pathway gliomas have been published recently in the following areas: neuroimaging, natural history and how the presence of neurofibromatosis type 1 affects it, unusual presentations, visual prognosis, and treatment with fractionated stereotactic radiotherapy.

SUMMARY

The diagnosis and treatment of optic-pathway gliomas has been aided greatly by a greater understanding of the natural history of these tumors and their prognosis related to the presence of neurofibromatosis type 1. Advances in magnetic resonance imaging are helping to delineate tumor extent. Newer radiation techniques that spare surrounding tissues are being used to treat optic-pathway gliomas, but chemotherapy has become the first-line treatment modality.

Rare syndromes

Dermatologists may also encounter patients presenting with skin lesions that reflect an underlying endocrine disorder not commonly seen in daily practice. Some of these endocrine disorders include glucagonoma, neurofibromatosis type 1, McCune-Albright syndrome, multiple endocrine neoplasia, the Carney complex, carcinoid tumors, and mastocytosis. The clinical syndrome classically associated with glucagonoma includes necrolytic migratory erythema, weight loss, diabetes mellitus, anemia, cheilitis, venous thrombosis, and neuropsychiatric symptoms. The hallmarks of neurofibromatosis type 1 are the multiple café-au-lait spots and associated cutaneous neurofibromas. Other presenting features include freckling, peripheral neurofibromas, Lisch nodules, bone abnormalities, tumors, neurologic abnormalities and hypertension. McCune-Albright syndrome is characterized by café-au-lait spots, polyostotic fibrous dysplasia, sexual precocity, and hyperfunction of multiple endocrine glands. Multiple endocrine neoplasia type 2A is characterized by medullary thyroid cancer, pheochromocytoma, and primary parathyroid hyperplasia. In some patients with multiple endocrine neoplasia type 2A, cutaneous lichen amyloidosis may also be present. Multiple endocrine neoplasia type 2B is characterized by medullary thyroid cancer and pheochromocytoma but not hyperparathyroidism. The syndrome also includes mucosal neuromas, typically involving the lips and tongue, intestinal ganglioneuromas and a marfanoid habitus. Multiple endocrine neoplasia type 1 is an autosomal dominant predisposition to tumors of the parathyroid glands (four-gland hyperplasia), anterior pituitary, and pancreatic islet cells; hence, the mnemonic device of the "3 Ps"; multiple cutaneous lesions (angiofibromas and collagenomas) are frequent in patients with multiple endocrine neoplasia type 1. Carney complex may be viewed as a form of multiple endocrine neoplasia because affected patients often have tumors of two or more endocrine glands, including primary pigmented nodular adrenocortical disease (some with Cushing's syndrome), pituitary adenoma, testicular neoplasms, thyroid adenoma or carcinoma, and ovarian cysts. Additional unusual manifestations include psammomatous melanotic schwannoma, breast ductal adenoma, and a rare bone tumor, osteochondromyxoma. Carcinoid syndrome is the term applied to a constellation of symptoms mediated by various humoral factors elaborated by some carcinoid tumors; the major manifestations are diarrhea, flushing, bronchospasm, and cardiac valvular lesions. Mast cell diseases include all disorders of mast cell proliferation. These diseases can be limited to the skin, referred to as "cutaneous mastocytosis," or involve extracutaneous tissues, called "systemic mastocytosis." Patients present with urticaria pigmentosa, mastocytoma, or diffuse cutaneous mastocytosis. Systemic involvement may be gastronintestinal, hematologic, neurologic, and skeletal.

Molecular, genetic, and cellular pathogenesis of neurofibromas and surgical implications

Neurofibromatosis 1 (NF1) is a common autosomal dominant disease characterized by complex and multicellular neurofibroma tumors. Significant advances have been made in the research of the cellular, genetic, and molecular biology of NF1. The NF1 gene was identified by positional cloning. The functions of its protein product, neurofibromin, in RAS signaling and in other signal transduction pathways are being elucidated, and the important roles of loss of heterozygosity and haploinsufficiency in tumorigenesis are better understood. The Schwann cell was discovered to be the cell of origin for neurofibromas, but understanding of a more complicated interplay of multiple cell types in tumorigenesis, specifically recruited heterogeneous cell types such as mast cells and fibroblasts, has important implications for surgical therapy of these tumors. This review summarizes the most recent NF1 and neurofibroma literature describing the pathogenesis and treatment of nerve sheath tumors. Understanding the biological underpinnings of tumorigenesis in NF1 has implications for future surgical and medical management of neurofibromas.

Symptoms associated with malignancy of peripheral nerve sheath tumours: a retrospective study of 69 patients with neurofibromatosis 1

BACKGROUND

Neurofibromatosis 1 (NF1) is a common genetic disorder with variable clinical manifestations and an unpredictable course. Plexiform neurofibromas are common complications of NF1. Their malignant transformation is the main cause of mortality in adult patients with NF1.

OBJECTIVES

To identify clinical factors associated with malignant transformation of plexiform neurofibromas.

METHODS

Using the database of our neurofibromatosis clinic we included in a retrospective study all patients with NF1 having at least one peripheral nerve sheath tumour for which they underwent surgery or surgical biopsy. Predictive values for malignant transformation of three clinical symptoms, i.e. pain, enlargement of mass and neurological symptoms, were evaluated in association with histological parameters.

RESULTS

Of 69 patients studied, 48 had at least one plexiform neurofibroma and 21 had a malignant peripheral nerve sheath tumour. Only enlargement of the tumour had high negative and positive predictive values for malignant transformation: 0.92 and 0.95, respectively. In multivariate analysis, tumour enlargement was independently associated with malignant transformation (odds ratio 167.8, 95% confidence interval 14.0-2012.1).

CONCLUSIONS

From a practical point of view, pain, neurological deficit and enlargement of a pre-existing peripheral nerve sheath tumour in NF1 must lead to deep surgical biopsy to rule out malignant transformation.

Neurocutaneous syndromes: behavioral features

Neurocutaneous syndromes are disorders characterized by a neurological abnormality and cutaneous manifestations. Three of the more common neurocutaneous syndromes are Sturge-Weber syndrome, tuberous sclerosis, and neurofibromatosis. This review focuses on the cognitive and behavioral features of these syndromes.

High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1

A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1) was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis). Among 55 patients (60% females, 40% males) who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous neurofibromas were observed in 96%, and 40% presented plexiform neurofibromas. A positive family history of NF1 was found in 60%, and mental retardation occurred in 35%. Some degree of scoliosis was noted in 49%, 51% had macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published.

Radiotherapy and Radiosurgery for Benign Neurofibromas

The purpose of this study was to evaluate the efficacy of radiotherapy (RT) and stereotactic radiosurgery (SRS) for neurofibromas. We studied 4 patients treated with RT (3 patients) or SRS (1 patient) and followed from 1.7 to 14.8 years. The tumor remained locally controlled in all patients. No significant complications related to treatment were observed. RT and SRS are likely to locally control neurofibromas in patients who require treatment and are not good candidates for complete resection.

Spinal deformity in neurofibromatosis type-1: diagnosis and treatment

Spinal deformity is the commonest orthopaedic manifestation in neurofibromatosis type-1 and is categorized into dystrophic and non-dystrophic types. Management should be based on a meticulous assessment of the spine with plain radiography and magnetic resonance imaging (MRI) to rule out the presence of dysplastic features that will determine prognosis and surgical planning. MRI of the whole spine should also be routinely obtained to reveal undetected intraspinal lesions that could threaten scheduled surgical interventions. Non-dystrophic curvatures can be treated with similar decision-making criteria to those applied in the management of idiopathic scoliosis. However, close observation is necessary due to the possibility of modulation with further growth and due to the increased reported risk of pseudarthrosis after spinal fusion. The relentless progressive nature of dystrophic curves necessitates aggressive operative treatment, which often has a significant toll on the quality of life of affected patients through their early childhood. Bracing of dystrophic curves has been unsuccessful. Combined anterior/posterior spinal arthrodesis including the entire structural component of the deformity is indicated in most cases, particularly in the presence of associated sagittal imbalance. This should be performed using abundant autologous bone graft and segmental posterior instrumentation to minimize the risk of non-union and recurrence of the deformity.

Childhood overgrowth in patients with common NF1 microdeletions

While growth retardation and short stature are well-known features of patients with classical neurofibromatosis type 1 (NF1), we found advanced height growth and accelerated carpal bone age in patients with an NF1 microdeletion. Our analysis is based on growth data of 21 patients with common 1.4/1.2 Mb microdeletions, including three patients with a Weaver-like appearance. Overgrowth was most evident in preschool children (2-6 years, n=10, P=0.02). We conclude that childhood overgrowth is part of the phenotypic spectrum in patients with the common 1.4/1.2 Mb NF1 microdeletions and assume that the chromosomal region comprised by the microdeletions contains a gene whose haploinsufficiency causes overgrowth.