Piezo2-related Arthrogryposis & physiopathOLOgy 3

Study type: Observational, non-interventional, single-center, descriptive study. Goal of the study: The goal of this observational study is to characterize the intensity, variability, and qualitative features of pain in patients with arthrogryposis multiplex congenita (AMC) caused by a gain-of-function mutation in PIEZO2. This population is rare and identified through the French national PARART registry (Pediatric and Adult Registry for patients with ARThrogryposis). Population: Participants are ≥10 years old, have a genetically confirmed gain-of-function PIEZO2 variant, and are registered in PARART. All procedures are conducted remotely; no onsite visit is required. Main questions the study aims to answer: * What is the intensity and day-to-day variability of pain over 14 consecutive days, measured with a Numerical Rating Scale (0-100)? * What are the sensory qualities and anatomical distribution of pain in this population? * How does this pain affect quality of life? * What treatments (pharmacological or non-pharmacological) have been used, and how effective are they? Study design: There is no comparison group. The study is descriptive and aims to characterize the pain phenotype linked to PIEZO2 gain-of-function mutations. What participants will do: Participants will complete the following tasks remotely: At Day 1: Questionnaires: * Saint-Antoine Pain Questionnaire (QDSA) * SF-12 * EQ-5D-5L * Pain monitoring: treatments used For 14 consecutive days (Day 1 to Day 14), on a paper logbook: * Daily self-reported Numerical Rating Scale (NRS, 0-100) for pain * Daily body chart to document pain distribution All data are collected through REDCap and a paper logbook. No clinical exam, biological sampling, or hospital visit is required. The study duration for each participant is 14 days.