A Pilot Study for Investigation of Plasma Amino Acid Profile in Neurofibromatosis Type 1 Patients

Background: Neurofibromatosis, also known as Von Recklinghausen disease, is a systemic and progressive genetic disease that primarily affects the skin, eyes, nervous system, and bones. The disease can occur in a variety of ways and can vary in individuals. Metabolomic-based research using blood samples has enabled new diagnostic methods to be used in the diagnosis of various diseases, especially cancer. Among the metabolites, profiling of plasma free amino acids (PFAA) is a promising approach because PFAAs bind all organ systems and play an important role in the metabolism. Objective: This study aimed to determine the characteristics of PFAA profiles in neurofibromatosis patients and the possibility of using them for early detection and treatment of the disease. Methods: Patients with a diagnosis of Neurofibromatosis Type I confirmed by genetic analysis and healthy individuals of the same age group without any disease were included in the study. We analysed the nineteen plasma free amino acids (phenylalanine, proline, threonine, arginine, asparagine, cystine, valine, glutamate, tyrosine, serine, glutamine, glycine, tryptophane, leucine, lysine, methionine, isoleucine, aspartate and alanine) from neurofibromatosis Type I patients and control group by liquid chromatography tandem mass spectrometry (LC-MS/MS) in Metabolism Laboratory of Harran University Research and Application Hospital. The results of the plasma free amino acid levels were divided into 3 groups as essential, semi-essential, and non-essential. The differences in amino acid levels between groups were determined. Results: The levels of eight amino acids (methionine, arginine, cystine, glutamine, proline, asparagine, serine, aspartate) were significantly altered in patients with neurofibromatosis type 1. In essential amino acids, methionine levels were significantly higher in the patient group than control group. While the levels of arginine and glutamine in semi-essential amino acids were statistically significantly higher in the patient group, a significant decrease was observed in cystine and proline levels compared to the control group's amino acid levels. In the non-essential amino acids group, asparagine, serine and aspartate amino acid levels were significantly higher in the patient group compared to the control group. Conclusion: The current research predicates that eight amino acids, namely methionine, arginine, cystine, glutamine, proline, asparagine, serine, aspartate can be considered to be valuable biomarkers for neurofibromatosis type I. This present study is the first to build models for neurofibromatosis Type I screening using plasma free amino acids and the amino acid profile will be able to guide the prediction of the complications that may occur during the course of the disease.