BackgroundDiagnosis of neuromuscular diseases in primary care is often challenging. Rare diseases such as Pompe disease are easily overlooked by the general practitioner. We therefore aimed to develop a diagnostic support tool using patient-oriented questions and combined data mining algorithms recognizing answer patterns in individuals with selected neuromuscular diseases. A multicenter prospective study for the proof of concept was conducted thereafter.MethodsFirst, 16 interviews with patients were conducted focusing on their pre-diagnostic observations and experiences. From these interviews, we developed a questionnaire with 46 items. Then, patients with diagnosed neuromuscular diseases as well as patients without such a disease answered the questionnaire to establish a database for data mining. For proof of concept, initially only six diagnoses were chosen (myotonic dystrophy and myotonia (MdMy), Pompe disease (MP), amyotrophic lateral sclerosis (ALS), polyneuropathy (PNP), spinal muscular atrophy (SMA), other neuromuscular diseases, and no neuromuscular disease (NND). A prospective study was performed to validate the automated malleable system, which included six different classification methods combined in a fusion algorithm proposing a final diagnosis. Finally, new diagnoses were incorporated into the system.ResultsIn total, questionnaires from 210 individuals were used to train the system. 89.5 % correct diagnoses were achieved during cross-validation. The sensitivity of the system was 93–97 % for individuals with MP, with MdMy and without neuromuscular diseases, but only 69 % in SMA and 81 % in ALS patients. In the prospective trial, 57/64 (89 %) diagnoses were predicted correctly by the computerized system. All questions, or rather all answers, increased the diagnostic accuracy of the system, with the best results reached by the fusion of different classifier methods. Receiver operating curve (ROC) and p-value analyses confirmed the results.ConclusionA questionnaire-based diagnostic support tool using data mining methods exhibited good results in predicting selected neuromuscular diseases. Due to the variety of neuromuscular diseases, additional studies are required to measure beneficial effects in the clinical setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s12911-016-0268-5) contains supplementary material, which is available to authorized users.

The L-arginine/nitric oxide (L-Arg/NO) pathway regulates endothelial function and may play an important role in the pathogenesis of Duchenne muscular dystrophy (DMD). Yet, this pathway is poorly investigated in children suffering from DMD. Endothelial dysfunction can affect the perfusion of contracting muscles, thus leading to ischemia and hypoxia. In the present study, we tested the hypothesis that reduced NO production due to elevated synthesis of N (G),N (G)-dimethyl-L-arginine (asymmetric dimethylarginine, ADMA), an endogenous inhibitor of NO synthesis, is a possible pathophysiological mechanism for progressive intramuscular muscle ischemia and disturbed endothelial function in children with DMD. Given the possible antagonistic action of homoarginine (hArg) on ADMA, we also analyzed this amino acid. We investigated 55 male patients with DMD and 54 healthy male controls (HC; aged 11.9 ± 4.8 vs. 11.1 ± 4.9 years, mean ± SD). Urinary creatinine and metabolites of the L-Arg/NO pathway were measured in plasma and urine by GC-MS or GC-MS/MS. Urine levels of ADMA and its major urinary metabolite dimethylamine (DMA), nitrite and nitrate (P < 0.001 for all) and hArg (P = 0.002) were significantly higher in DMD patients compared to HC, while the urinary DMA/ADMA molar ratio was lower (P = 0.002). In plasma, nitrate (P < 0.001), hArg (P = 0.002) and the hArg/ADMA ratio (P < 0.001) were lower in DMD than in HC. In plasma, ADMA (631 ± 119 vs. 595 ± 129 nM, P = 0.149), arginine and nitrite did not differ between DMD and HC. In DMD, positive correlations between ADMA, DMA or nitrate excretion and the stage of disease (according to Vignos and Thompson) were found. In DMD patients on steroid medication, lower concentrations of ADMA in plasma, and of DMA, ADMA, nitrate and hArg in urine were observed compared to non-treated patients. The L-Arg/NO pathway is impaired in DMD patients, with the disease progression being clinically negatively correlated with the extent of impairment. One of the underlying mechanisms in DMD may involve insufficient antagonism of ADMA by hArg. Steroids, but not creatine supplementation, seems to improve the L-Arg/NO pathway in DMD.

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