Clinical evaluation of muscle functions in neurofibromatosis type 1

Abstract

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.

Loss of neurofibromin accelerates uveal and dermal melanoma formation driven by GNAQ

“…There are also some interesting muscle connections in the literature. For example, neurofibromin has been shown to be required for skeletal muscle development and function in mice [55] and individuals with neurofibromatosis type 1 experience hypotonia, decreased strength and reduced motor function [57]. Most intriguingly, people with myotonic dystrophy, which is caused by autosomal dominant repeat expansions disrupting the first exons of the muscle genes, DMPK (in type 1) or CNBP (in type 2), develop a significantly elevated number of thyroid, endometrium, ovary, melanoma, colon/rectum, and testis cancers [58].…”

Variability of joint hypermobility in children: a meta-analytic approach to set cut-off scores

“…This occurred in 19 studies [4,[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], potentially impacting the intra or inter-rater reliability. Additionally, there were 14 studies reporting the response rate [1,3,4,14,18,22,24,27,29,[32][33][34][35][36], while the other studies were unclear or had a low response rate without adequately described overall responses. The strength of the vast majority of studies was the validity of the measures researchers employed to collect the data, in addition to their description of the participants enabling inclusion as data representative of the community.…”

“…Prevalence data were extracted from 34 of the 37 studies with data of children rated as having a Beighton score of ≥ 4. The studies were additionally pooled on sex and world region: Eastern Europe and Russia: n = 3 [4,26,37], Middle East: n = 4 [19,25,32,36], North America: n = 2 [28,38], Oceania: n = 3 [1,18,21], South America: n = 2 [17,24], South and South East Asia: n = 5 [14,15,23,29,30] and Western Europe: n = 15 [2,3,5,16,20,27,31,[33][34][35][39][40][41][42][43]. In total, 25,060 children were included (reported male = 11,853 and female n = 11,441), grand mean age: 12.3 years (Table 1).…”

“…Prevalence data were extracted from 21 of the 37 studies with data of children rated as having a Beighton score of ≥ 6. The studies were additionally pooled on world region (Eastern Europe and Russia: n = 1 [4], Middle East: n = 3 [25,32,36], North America: n = 2 [28,38], Oceania: The prevalence of a Beighton score of ≥ 6 varied between 2.6 and 44.4%, with a grand mean prevalence of 11% (Fig. 3).…”