Speech characteristics in neurofibromatosis type 1

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

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

Clinical evaluation of muscle functions in neurofibromatosis type 1

AIM

Muscle weakness, fatigue and speech problems can occur in neurofibromatosis type 1 (NF1). The pathogenesis of these symptoms is unclear, likely multifactorial. We examined motor function in limb and speech muscles in NF1 patients.

METHODS

We evaluated NF1 and control groups aged 4-18 years for muscle strength, tone and mobility using standard manual testing, joint motion and Beighton score measurements. Speech and language functions were assessed by speech articulation and resonance. As a marker of muscle tissue turnover, we determined collagen degradation products in urine before and after submaximal exercise.

RESULTS

NF1 patients had reduced strength in proximal limb muscles compared to control subjects. Speech articulation problems and hypernasality were more common in NF1 (47% and 38%, respectively). Collagen products excreted in urine correlated with gluteal and biceps muscle strength.

CONCLUSION

Muscle dysfunction can be detected in some children with NF1 and may explain certain clinical features including fatigue, speech and articulation problems. If confirmed by further research, these findings may be relevant to the management of this condition.

Speech Outcomes Following Orticochea Pharyngoplasty in Patients With History of Cleft Palate and Noncleft Velopharyngeal Dysfunction

OBJECTIVE

To report speech outcomes following Orticochea pharyngoplasty in 43 patients with cleft palate and noncleft velopharyngeal dysfunction.

DESIGN

A retrospective surgical audit of patients undergoing Orticochea pharyngoplasty between 2004 and 2012, with speech as a primary outcome measure.

SETTING

Patients known to a regional UK cleft center.

METHODS

Forty-three patients underwent Orticochea pharyngoplasty by a single surgeon in a UK regional cleft center. Twenty-one patients had undergone a prior procedure for velopharyngeal dysfunction. Pre- and postoperative speech samples were assessed blindly using the Cleft Audit Protocol for Speech-Augmented by a specialist cleft speech and language therapist, external to the team. Speech samples were rated on the following parameters: hypernasality, hyponasality, audible nasal emission, nasal, turbulence, and passive cleft speech characteristics. Statistical differences in pre- and postoperative speech scores were tested using the Wilcoxon matched-pairs signed-ranks test. Inter- and intrareliability scores were calculated using weighted Cohen κ.

RESULTS

Whole group: A statistically significant difference in pre- and postoperative scores for hypernasality (P < .001), hyponasality (P < .05), nasal emission (P < .01), and passive cleft speech characteristics (P < .01) were reported. Patients with cleft diagnoses: A statistically significant difference in scores for hypernasality (P < .001), nasal emission (P < .01), and passive cleft speech characteristics (P < .01) were reported for this group of patients. Patients with noncleft diagnoses: The only parameter to demonstrate a statistically significant difference was hypernasality (P < .01) in this group.

CONCLUSIONS

Orticochea pharyngoplasty is a successful surgical procedure in treating velopharyngeal dysfunction in both the cleft and noncleft populations.

A rare disease and education: Neurofibromatosis type 1 decreases educational attainment

Rare heritable syndromes may affect educational attainment. Here, we study education in neurofibromatosis 1 (NF1) that is associated with multifaceted medical, social and cognitive consequences. Educational attainment in the Finnish population‐based cohort of 1408 individuals with verified NF1 was compared with matched controls using Cox proportional hazards model with delayed entry and competing risk for death. Moreover, models accounting for the effects of cancer at age 15–30 years, parental NF1 and developmental disorders were constructed. Overall, the attainment of secondary education was reduced in individuals with NF1 compared to controls (hazard ratio 0.83, 95%CI 0.74–0.92). History of cancer and developmental disorders were major predictors of lack of secondary education. Individuals with NF1 obtained vocational secondary education more often than general upper secondary education. Consequently, NF1 decreased the attainment of Bachelor's and Master's degrees by 46%–49% and 64%–74%, respectively. Surprisingly, the non‐NF1 siblings of individuals with NF1 also had lower educational attainment than controls, irrespective of parental NF1. In conclusion, NF1 is associated with reduced educational attainment and tendency for affected individuals to obtain vocational instead of academic education. Individuals living with NF1, especially those with cancer, developmental disorders or familial NF1, need effective student counseling and learning assistance.

Speech difficulties and patient health communication mediating effects on worry and health-related quality of life in children, adolescents, and young adults with Neurofibromatosis Type 1

The objective was to investigate the serial mediating effects of speech difficulties, patient health communication, and disease-specific worry in the relationship between neurofibromatosis (NF) symptoms (pain and skin symptoms) and total generic health-related quality of life (HRQOL) in children, adolescents, and young adults with NF Type 1 (NF1) from the patient perspective. The Speech, Communication, Worry, Pain, Skin Itch Bother, and Skin Sensations Scales from the Pediatric Quality of Life Inventory (PedsQL) NF1 Module and the PedsQL 4.0 Generic Core Scales were completed in a multi-site national study by 305 patients ages 5-25 years. A serial multiple mediator model analysis was conducted to test the hypothesized sequential mediating effects of speech difficulties, health communication, and worry as intervening variables in the association between NF1 symptoms and HRQOL. Symptoms predictive effects on total generic HRQOL were serially mediated by speech difficulties, patient health communication, and worry. In predictive analytics models utilizing hierarchical multiple regression analyses with age and gender demographic covariates, the pain, skin itch bother, and skin sensations multiple mediator models accounted for 61%, 59%, and 56% of the variance in generic HRQOL (p < .001), reflecting large effect sizes. Speech difficulties, patient health communication, and disease-specific worry explain in part the mechanism of symptoms predictive effects on total generic HRQOL in pediatric patients with NF1. Identifying NF1-specific predictors and serial mediators of total generic HRQOL in pediatric patients with NF1 from the patient perspective enables a patient-centered comprehensive care approach for children, adolescents, and young adults with NF1.

Health Supervision for Children With Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a multisystem disorder that primarily involves the skin and peripheral nervous system. Its population prevalence is approximately 1 in 3000. The condition is usually recognized in early childhood, when pigmentary manifestations emerge. Although NF1 is associated with marked clinical variability, most children affected follow patterns of growth and development within the normal range. Some features of NF1 can be present at birth, but most manifestations emerge with age, necessitating periodic monitoring to address ongoing health and developmental needs and minimize the risk of serious medical complications. In this report, we provide a review of the clinical criteria needed to establish a diagnosis, the inheritance pattern of NF1, its major clinical and developmental manifestations, and guidelines for monitoring and providing intervention to maximize the health and quality of life of a child affected.

Neurofibromatosis type 1 of the child increases birth weight

Neurofibromatosis type 1 (NF1) is associated with reduced adult height, but there are no cohort studies on birth size. This retrospective study includes a cohort of 1,410 persons with NF1 and a matched comparison cohort from the general population. Figures for birth size were retrieved from the administrative registers of Finland, and the data were converted to standard deviation scores (SDS), defined as standard deviation difference to the reference population. The birth weight among infants with NF1 was higher than among infants without the disorder (adjusted mean difference [95% confidence interval]: 0.53 SDS [0.19–0.87]), as was the head circumference at birth (0.58 SDS [0.26–0.90]). The birth length of the NF1 infants did not differ significantly from the comparison cohort. The birth weight in the group consisting of NF1 and non‐NF1 infants of NF1 mothers was lower than among infants of mothers in the comparison cohort (−0.28 SDS [−0.51 to −0.06]), as was the birth length (−0.22 SDS [−0.45 to 0.00]). In conclusion, the birth weight and head circumference of persons with NF1 are significantly higher than those of persons without the disorder. NF1 of the mother reduces birth weight and birth length of the infant.

Craniofacial and oral alterations in patients with Neurofibromatosis 1

ABTSRACT

Neurofibromatosis type 1 (NF1) is one of the most common inherited syndromes. The literature on craniofacial alterations associated with NF1 has been limited and partially contradictory. This review is based on literature search and the results of the clinical study "Craniofacial and Oral Alterations and Speech in patients with Neurofibromatosis 1", carried out at the University of Turku and Turku University Hospital, Finland in 2006-2012. By the end of 2012, a total of 110 NF1 patients, 54 female and 56 male patients, were examined.A part of our results confirms pre-existing understanding, a part is contradictory to previous considerations based mainly on case reports, and some are entirely novel. Specifically, our results confirmed that enlargement the mandibular canal is the most common abnormality of the mandible in patients with NF1. It should be noted, however, that this finding does not require treatment. Caries was not a major problem. In fact, it was less frequent in NF1 patients compared to reference population. These findings abrogate some previous perceptions. Novel findings of our project include periapical cemental dysplasia in females; short jaws, a finding which usually does not affect bite; and immunohistological analysis of oral mucosal abnormalities. Pioneering study on speech showed that various deviations were very common: As many as 94% of the participants showed some alterations.To conclude, the awareness of craniofacial alterations common in NF1would help avoiding unnecessary and even harmful involvement, e.g. of periapical cemental dysplasia or enlarged mandibular canal which do not require treatment.

Congenital anomalies in neurofibromatosis 1: a retrospective register-based total population study

Background

Neurofibromatosis type 1 (NF1) is a dominantly inherited Rasopathy caused by mutations in the NF1 gene on chromosome 17. NF1 has been connected to congenital anomalies, e.g., in the skeletal and cardiovascular systems, but the overall incidence of anomalies is unknown. In this retrospective register-based total population study conducted in Finland, the congenital anomalies in NF1 were evaluated.

Methods

One thousand four hundred ten patients with NF1 were identified by searching the medical records related to inpatient and outpatient hospital visits of patients with an associated diagnosis for NF1 in 1987–2011. Each diagnosis was confirmed by a thorough review of the medical records. Ten non-NF1 control persons per NF1 patient were collected from the Population Register Centre. NF1 patients and controls were linked to the Medical Birth Register and the Register of Congenital Malformations. Odds ratios (OR) and 95% confidence intervals (95% CI) for major congenital anomalies (MCA) were calculated.

Results

The OR for at least one MCA among NF1 children was almost threefold (adjusted OR 2.78, 95% CI 1.71–4.54) compared to controls matched for age, sex and municipality. NF1 children had a significantly increased risk of congenital anomalies in the circulatory (adjusted OR 3.35, 95% CI 1.64–6.83), urinary (adjusted OR 4.26, 95% CI 1.36–13.35) and musculoskeletal (adjusted OR 2.77, 95% CI 1.09–7.02) systems. Also, anomalies of the eye, ear, head and neck were more common among NF1 children than controls (adjusted OR 4.66, 95% CI 1.42–15.31). Non-NF1 children of mothers with NF1 did not have more anomalies than controls (adjusted OR 0.53, 95% CI 0.13–2.21).

Conclusions

Children with NF1 have more MCAs than controls and close follow-up during pregnancy and the neonatal period is required if the mother or father has NF1. Non-NF1 children of mothers with NF1 do not have an increased risk for anomalies.

The pregnancy in neurofibromatosis 1: A retrospective register-based total population study

The objective of this retrospective total population study was to form a view of the pregnancies of the patients with neurofibromatosis type 1 (NF1). A cohort of 1,410 Finnish patients with NF1 was acquired by searching NF1-related inpatient and outpatient hospital visits and confirming the diagnoses by reviewing the medical records. Ten matched control persons per patient with NF1 were collected from Population Register Centre. Study persons were linked to data from Medical Birth Register and Care Register for Health Care through the personal identity code. Cesarean deliveries, hypertension/preeclampsia, and placental abruptions were more common among mothers with NF1 with adjusted odds ratios of 2.24 (95%CI 1.63-3.07), 1.96 (95%CI 1.18-3.24), and 13.40 (95%CI 4.26-42.13), respectively. The adjusted mean pregnancy duration was 0.65 (95%CI 0.42-0.88) weeks shorter among the mothers with NF1 than in the control group consisting of non-NF1 mothers giving birth to a non-NF1 child. The pregnancies of non-NF1 mothers giving birth to a NF1 child were 0.43 (95%CI 0.24-0.62) weeks shorter than in the control group. In summary, NF1 of the mother was associated with a shortened pregnancy and increased pregnancy complications. Also, the NF1 of the fetus slightly shortened pregnancy. Since mothers with NF1 are at increased risk for pregnancy complications, careful evaluation of their pregnancies is warranted.

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.

Cognitive and Behavioral Disorders in Children with Neurofibromatosis Type 1

AIM

The last systematic review of research on the behavior of children with neurofibromatosis type 1 (NF1) was in 2012. Since then, several important findings have been published. Therefore, the study aim was to synthesize recent relevant work related to this issue.

METHOD

We conducted a systematic review of the literature. Relevant articles were identified using the electronic databases PubMed, PsycINFO, and Scopus and a manual search of references lists. Thirty of 156 articles identified met the inclusion criteria. A quality evaluation of the articles was performed and the information was synthesized using a narrative approach.

RESULTS

Compared with controls, children and adolescents with NF1 present significant alterations in language, reading, visuospatial skills, motor function, executive function, attention, behavior, emotion, and social skills. The prevalence of attention-deficit/hyperactivity disorder (ADHD) is important and can affect cognition and executive function variables. A high prevalence of autistic traits and autistic spectrum disorder were reported. The benefits of using statins to treat cognitive deficits are unclear. However, children with NF1 and ADHD seem to benefit from methylphenidate treatment. The presence of hyperintensities in brain magnetic resonance imaging data seem to be related to poor cognitive performance. Analysis of these lesions could help to predict cognitive alterations in children with NF1.

INTERPRETATION

There has been important progress to evaluate cognitive characteristics of children with NF1 and to determine the physiological mechanisms of the concomitant disorders. However, discrepancies in relation to intelligence, learning disabilities, attention deficits, and treatment remain. Further investigations on this topic are recommended.

Laryngeal Manifestations of Neurofibromatosis

Objectives

To describe the range of findings in patients with neurofibromatosis (NF) presenting to a laryngology clinic and to analyze the etiologic factors of vocal fold dysfunction in this cohort.

Study Design

Case series with chart review.

Setting

Tertiary laryngology practice.

Subjects and Methods

All cases of NF presenting to an academic laryngology practice were retrospectively reviewed (August 2005 to May 2014), with a total of 34 cases. Demographic data, symptoms, and endoscopic examination findings were reviewed. Etiologic factors of laryngeal complaints were analyzed with reference to NF-associated pathologies and surgical history.

Results

Thirty-four patients with NF-1 or NF-2 were evaluated, and 28 of these patients (6 NF-1 and 22 NF-2) had laryngeal pathology. The most common presenting symptoms were vocal weakness (n = 21), dysphagia (n = 5), and globus (n = 4). Three patients had NF-related vocal fold masses on examination, including 2 neurofibromas and 1 schwannoma. Unilateral vocal cord paralysis was seen in 17 patients; bilateral paralysis was observed in 5 patients. Of patients with unilateral or bilateral paralysis, 20 had intracranial masses (vestibular schwannoma, meningioma, or skull base tumors), and 16 had previously undergone surgery for these lesions. Of the patients with NF-associated intracranial tumors, 87.0% presented with vocal cord paralysis, whereas only 40.0% of those without intracranial masses had paralysis ( P = .0560). Seven patients underwent medialization procedures.

Conclusion

Neurofibromatosis patients may present to laryngology clinic with primary laryngeal tumors or, more commonly, unilateral or bilateral paralysis. Otolaryngologists should be keenly aware of vocal fold paralysis caused by the NF-associated tumors, with particular attention to bilateral paralysis in NF-2.

A RASopathy gene commonly mutated in cancer: the neurofibromatosis type 1 tumour suppressor

Neurofibromatosis type 1 (NF1) is a common genetic disorder that predisposes affected individuals to tumours. The NF1 gene encodes a RAS GTPase-activating protein called neurofibromin and is one of several genes that (when mutant) affect RAS-MAPK signalling, causing related diseases collectively known as RASopathies. Several RASopathies, beyond NF1, are cancer predisposition syndromes. Somatic NF1 mutations also occur in 5-10% of human sporadic cancers and may contribute to resistance to therapy. To highlight areas for investigation in RASopathies and sporadic tumours with NF1 mutations, we summarize current knowledge of NF1 disease, the NF1 gene and neurofibromin, neurofibromin signalling pathways and recent developments in NF1 therapeutics.

Tumors perturbing extracellular matrix biosynthesis. The case of von Recklinghausen's disease

This is a short review of neurofibromatosis-1 or von Recklinghausen's disease, due to a loss of function mutation of the gene neurofibromin-1, which normally inhibits the Ras MAPK-pathways. Among its symptoms, the strong oversynthesis of several collagen types designates this disease as producing a deregulation of extracellular matrix biosynthesis involved in tumor formation. Up to about 40% of the skin tumors consist of collagens. A short summary of the clinical manifestations and pathological and genetic mechanisms are also described.

Behaviour in children with neurofibromatosis type 1: cognition, executive function, attention, emotion, and social competence

AIM

This systematic review aimed to pull together the findings from research into behavioural systems and attention in children with neurofibromatosis type 1 (NF1) and to identify areas that need further study.

METHOD

Relevant papers were identified through searches of electronic databases (MEDLINE, PsycINFO, EMBASE) and manual searches through reference lists. In total, 5746 articles were identified and 57 met the inclusion criteria. The data were synthesized using the narrative approach, as the studies varied considerably in terms of participants and measures.

RESULTS

The results of the review showed that intelligence, academic skills, visuospatial skills, social competence, and attention are impaired in children with NF1. Evidence of deficits in memory, motor functioning, language, and executive functions was less clear.

INTERPRETATION

Research has made marked progress in outlining the behavioural phenotype of NF1. However, although the general areas of impairment are becoming better known, the exact nature of the impairment is still not understood in many areas of behaviour. Care needs to be taken with the way in which behavioural constructs are defined and measured, and the variability of problems in NF1 is a particular challenge. Nevertheless, research is steadily moving towards comprehensive understanding of behaviour in children with NF1.

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.

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.

The pathoetiology of neurofibromatosis 1

Although a mutation in the NF1 gene is the only factor required to initiate the neurocutaneous-skeletal neurofibromatosis 1 (NF1) syndrome, the pathoetiology of the multiple manifestations of this disease in different organ systems seems increasingly complex. The wide spectrum of different clinical phenotypes and their development, severity, and prognosis seem to result from the cross talk between numerous cell types, cell signaling networks, and cell-extracellular matrix interactions. The bi-allelic inactivation of the NF1 gene through a "second hit" seems to be of crucial importance to the development of certain manifestations, such as neurofibromas, café-au-lait macules, and glomus tumors. In each case, the second hit involves only one cell type, which is subsequently clonally expanded in a discrete lesion. Neurofibromas, which are emphasized in this review, and cutaneous neurofibromas in particular, are known to contain a subpopulation of NF1-diploinsufficient Schwann cells and a variety of NF1-haploinsufficient cell types. A recent study identified a multipotent precursor cell population with an NF1(+/-) genotype that resides in human cutaneous neurofibromas and that has been suggested to play a role in their pathogenesis.

Oral soft tissue alterations in patients with neurofibromatosis

Our aim was to characterize the type and frequency of oral soft tissue alterations in neurofibromatosis. A total of 103 patients with neurofibromatosis 1 (NF1) and three patients with neurofibromatosis 2 (NF2) were clinically evaluated for their oral soft tissue alterations. Disturbing growths were removed from nine patients with NF1 and from one patient with NF2. The specimens were analyzed using routine histological methods and with immunohistochemistry using antibodies to S100, type IV collagen, CD34, neurofilament, and neuron-specific tubulin (TUBB3). Alterations including oral tumors, overgrowths of gingival soft tissue, and enlarged papillae of the tongue were discovered in 74% of NF1 patients. The results showed that three tumors clinically classified as plexiform neurofibromas and five out of six discrete mucosal tumors displayed histology and immunohistology consistent with that of neurofibroma. The histology of one palatal lesion resembled that of a scar, and the lesion removed from the patient with NF2 was classified as an amyloid tumor. To conclude, oral soft tissue growths are common findings in NF1, but most lesions do not require treatment and the patients may even not be aware of these alterations. Collagen IV, S100, and CD34 are useful biomarkers in the analysis of NF1-related oral soft tissue tumors. The clinicians should recognize that oral soft tissue alterations are relatively common in NF1. Some of the growths are disturbing, and plexiform neurofibromas may bear a risk of malignant transformation.