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

Trovó-Marqui, A.B.; Goloni-Bertollo, Eny Maria; Valerio, Nelson Iguimar; Pavarino, Érika Cristina; Muniz, Marcos Pontes; Teixeira, Marta; Antônio, Joäo Roberto; Tajara, EH

doi:10.1590/s0100-879x2005000900020

Cited by 20 publications

(19 citation statements)

References 30 publications

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“…22 In addition, 13 of the 29 men (44.8%) and 6 of the 31 women (19.4%) were overweight, while in the Brazilian adult population, this prevalence is 49% (50.1% in men and 48% in women). 22 Short stature was present in 28.3% of the sample, which was higher than seen in a study by Petramala et al, 7 and lower than seen in the studies of Souza et al 4 and Trovo-Marques et al 8 These studies were conducted in different age groups, and also included children in the analyses. In the Brazilian population survey, 22 the average height (in centimeters) of adults living at the same region in Brazil was high compared to patients with NF1 of this study.…”

Section: Discussionmentioning

confidence: 76%

“…However, NF1 can also exhibit multisystemic involvement including musculoskeletal, cardiovascular, endocrine, ophthalmic, central and peripheral neural system, learning deficits and speech disorders. [3][4][5] Recently, the first study of nutrient intake in NF1 patients was published, 6 and, although the clinical manifestations of NF1 are well established, data on body composition are scarce 4,[7][8][9][10] and not well known. Low weight, short stature, and reduced body mass index (BMI) were found previously in NF1 patients and can be used as nutritional status indicators.…”

Section: Introductionmentioning

confidence: 99%

“…However, these characteristics had different prevalence rates in the small number of studies available. 4,[7][8][9][10] Most of these studies were conducted in children only, or included children and adults in the same sample.…”

Section: Introductionmentioning

confidence: 99%

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Body composition in adults with neurofibromatosis type 1

Souza

Jansen

Martins

et al. 2016

Rev. Assoc. Med. Bras.

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SUMMARY Objective To evaluate the body composition and nutritional status of neurofibromatosis type 1 (NF1) adult patients. Method A cross-sectional study of 60 NF1 patients (29 men, 31 women) aged ≥ 18 years who were evaluated from September 2012 to September 2013 in a Neurofibromatosis Outpatient Reference Center. Patients underwent nutritional assessment including measurements of weight, stature, waist circumference (WC), upper-arm circumference (UAC), and skinfolds (biceps, triceps, subscapular, suprailiac). Body mass index (BMI), upper-arm total area (UATA), upper-arm muscle area (UAMA), upper-arm fat area (UAFA), body fat percentage (BFP), fat mass, fat-free mass, fat mass index, and fat-free mass index were also calculated. Results The mean age of the study population was 34.48±10.33 years. The prevalence of short stature was 28.3%. Low weight was present in 10% of the sample and 31.7% of patients had a BMI ≥ 25 kg/m2. Reduced UAMA (<5th percentile) was present in 43.3% and no difference was found in UAFA between the sexes. The BFP was considered high in 30% and 17 (28.3%) patients had a WC above the World Health Organization cutoffs. Conclusion In this study, NF1 patients had a high prevalence of underweight, short stature, and reduced UAMA, with no difference between the sexes. Reduced UAMA was more prevalent in underweight patients; however, this was also observed in the normal and overweight patients. Further studies should investigate the distribution of body tissues in NF1 patients, including differences between men and women, and the influence of diet and nutrition on clinical features in NF1.

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Section: Discussionmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

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Body composition in adults with neurofibromatosis type 1

Souza

Jansen

Martins

et al. 2016

Rev. Assoc. Med. Bras.

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“…Neurofibromin is expressed abundantly in the nervous system (Daston et al 1992). The high incidence of learning deficits and exaggerated painful responses (Creange et al 1999;North et al 1997;Ozonoff 1999;Trovo-Marqui et al 2005) indicate that the single active NF1 allele does not generate sufficient functional neurofibromin to fulfill its normal biological role in the nervous system. Neurofibromin facilitates switching the active form of Ras (Ras-GTP) to its inactive form (Ras-GDP) by serving as a GTPase activating protein (GAP).…”

Section: Introductionmentioning

confidence: 99%

Augmented Sodium Currents Contribute to the Enhanced Excitability of Small Diameter Capsaicin-Sensitive Sensory Neurons Isolated From Nf1+/− Mice

Wang¹,

Duan²,

Hingtgen

et al. 2010

Journal of Neurophysiology

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Wang Y, Duan JH, Hingtgen CM, Nicol GD. Augmented sodium currents contribute to the enhanced excitability of small diameter capsaicin-sensitive sensory neurons isolated from Nf1ϩ/Ϫ mice. J Neurophysiol 103: 2085-2094, 2010. First published February 17, 2010 doi:10.1152/jn.01010.2009. Neurofibromin, the product of the Nf1 gene, is a guanosine triphosphatase activating protein (GAP) for p21ras (Ras) that accelerates conversion of active Ras-GTP to inactive Ras-GDP. Sensory neurons with reduced levels of neurofibromin likely have augmented Ras-GTP activity. We reported previously that sensory neurons isolated from a mouse model with a heterozygous mutation of the Nf1 gene (Nf1ϩ/Ϫ) exhibited greater excitability compared with wild-type mice. To determine the mechanism giving rise to the augmented excitability, differences in specific membrane currents were examined. Consistent with the enhanced excitability of Nf1ϩ/Ϫ neurons, peak current densities of both tetrodotoxin-resistant sodium current (TTX-R I Na ) and TTX-sensitive (TTX-S) I Na were significantly larger in Nf1ϩ/Ϫ than in wild-type neurons. Although the voltages for half-maximal activation (V 0.5 ) were not different, there was a significant depolarizing shift in the V 0.5 for steady-state inactivation of both TTX-R and TTX-S I Na in Nf1ϩ/Ϫ neurons. In addition, levels of persistent I Na were significantly larger in Nf1ϩ/Ϫ neurons. Neither delayed rectifier nor A-type potassium currents were altered in Nf1ϩ/Ϫ neurons. These results demonstrate that enhanced production of action potentials in Nf1ϩ/Ϫ neurons results, in part, from larger current densities and a depolarized voltage dependence of steady-state inactivation for I Na that potentially leads to a greater availability of sodium channels at voltages near the firing threshold for the action potential.

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“…Os neurofibromas plexiformes foram observados em 34,1% dos pacientes. Esta prevalência é semelhante à descrita em 55 pacientes brasileiros, e um pouco mais elevada do que a descrita na literatura mundial 21 . Outro estudo também realizado no Brasil detectou a prevalência de neurofibromas plexiformes em 26,9% das 104 crianças e adolescentes avaliados 22 .…”

Section: Discussionunclassified