FIbromyalgia anD GenetIcs Subgroups (FIDGIS)

Patient rested comfortably in a supine position in order to obtain muscular relaxation. Cutaneous electrodes will be applied, and the sural nerve will be stimulated in its retromaleolar track. Electromyographic responses will recorded using the Nicolet Vicking device with a pair of surface electrodes placed over the tendon of the ipsilateral biceps femoris.

The R-III reflex (objective threshold) will be identified as a multiphasic signal appearing at least 90 ms but less than 250 ms after each stimulation and will be considered to be present when the corrected computed surface was >0.5 mV/ms (positive response).

Genome-wide association studies highlight that genetic factors are possibly responsible for up to 50% of the disease susceptibility, and several potential candidate genes have been found to be associated to fibromyalgia, including catecholaminergic (COMT), serotoninergic (HTR2A, SLC6A4), dopaminergic (GCH1, TAAR1) and glutamatergic (GRIA4) pathways. The participants will be genotyped for selected SNPs (120 SNPs- OpenArray technology) that have been previously investigated in relation to FM susceptibility, symptoms or potential mechanisms (Algynomics and international publications).

A single blood sample will be obtained on visit 1 day 1 and 4 aliquotes will be frozen at -80°C and kept frozen until the Open Array Technology analysis

assessed by Central Sensitization Inventory questionnaire

The mechanical temporal summation test will be performed using a 180g (Size 6.45) Von Frey filament applied to the non-dominant arm of the patient/subject who are sitting comfortably in a quiet room. The Von Frey filament will be applied against the skin of the participant at right angle, the manipulator performs a pressure movement until the filament flexes slightly. The participant scores on a numerical verbal scale (0 to 10) the intensity of pain perceived by the application of a single stimulus, and then of ten stimuli

This self-assessment scale allows the patient to characterize the pain in relation to its psychosocial intensity and impact. The patient is asked to answer 9 graduated questions by circling a number from 0 (no pain) to 10 (the most horrible pain you can imagine). Among these questions the patient is asked to blacken the painful areas on a diagram and to put an S if the pain is on the surface or a P if it is deep

The FIRST questionnaire is a 6-item self-questionnaire that detects fibromyalgia. The patient is asked to answer "yes" or "no". Five "yes" allow to detect fibromyalgia when pain has persisted for more than 3 months

The revised FIQ questionnaire is a 10-item self-questionnaire that assesses the impact of fibromyalgia. The first item is subdivided into 10 questions that assess the impact of the disease in everyday life

The experimenter makes a palpate-roll (by slightly lifting the skin) between the thumb and the other 4 fingers of the hand by following an axis on each side of the patient's spine. The palpate roll begins at the lumbar level and rises to the level of the shoulder blades on each side of the spine. The test is performed on one side of the spine and then on the other. The palpate roll should be performed 5 times on each side of the spine alternately. The investigator should rate for each side and at each pass whether the patient is experiencing pain or not. If the patient does not feel pain after 5 passes, the test is considered negative.

the quality of life of the participants will be assessed by the self-administrated General Questionnaire 36-Item Short Form Survey (SF-36). The SF-36 questionnaire consists of 36 items and assesses an individual's physical and mental health using eleven questions related to eight aspects of health: physical function, role physical, bodily pain, general health, vitality, social function, role emotional, mental health.Global score ranges from 0 to 100.

The Hospital Anxiety and Depression scale is a self-administered questionnaire in 14 items completed by the participant. It is used to determine the levels of anxiety and depression. Seven of the items relate to anxiety and seven relate to depression. Global score ranges from 0 to 42.

Studies have shown that thousands of human protein coding genes are regulated by micro RNAs, indicating that micro RNAs are "master regulators" of many important biological processes and some of this microRNA can be implicated in fibromyalgia continuum. The participants micro RNA's will be analyzed for 754 human selected micro RNA (OpenArray technology) that have been previously investigated in relation to FM susceptibility, symptoms or potential mechanisms. A single blood sample will be obtained on visit 1 day 1 and 6 aliquotes will be frozen at -80°C and kept frozen until the Open Array Technology analysis.

Identification of bacterial biodiversity by a genetic sequencing analysis of bacterial DNA. The stool samples will be collected and then frozen at -80°C and kept frozen until analysis.

the sensitivity to pain of the participants will be assessed by the Pain Sensitivity Questionnaire (PSQ). The PSQ questionnaire explore natural sensitivity to pain using questions simulating more or less intense pain situation using 17 questions.

the uncomfortable loudness level (ULL) of the participants will be assessed using the procedure of the British audiology society using a conventional audiometer (pure sound emission). The ULL is the level at which the participant responds or clearly feels uncomfortable and confirms this fact after removing the helmet.

the light sensitivity level of the participants will be assessed using a led panel (Lykos Daylight, Manfrotto) in a room without any source of natural light. The light intensity will be progressive (by step of 1 seconds flash light every 20 seconds) and the participant will stop the test when the intensity of the light will be uncomfortable. The light sensitivity is the level at which the participant feels uncomfortable