Long-read Genome Sequencing for the Molecular Diagnosis of Dystonia

Inclusion criteria - Index case: * Index case affected by familial dystonia (≥1 first-degree relative affected) and/or sporadic early-onset dystonia (symptom onset before age 50), meeting the criteria of the PFMG-2025 program. * Index case who has undergone short-read genome sequencing, which did not lead to a molecular diagnosis. * Ability to understand and sign informed consent by the index case and/or their parents or legal guardians for patients under 18 years of age. * Availability of a blood sample from the index case and at least two relatives, either affected or unaffected. Inclusion criteria - Relatives: * Symptomatic or asymptomatic relative of an index case, who has also undergone short-read genome sequencing without a conclusive molecular diagnosis. * Ability to understand and sign informed consent. Exclusion criteria: * Index case or relatives who are not affiliated with or not beneficiaries of a social security scheme. * Index case and their parents presenting with a condition that, in the opinion of the investigator, would contraindicate participation in the study. * Suspected non-genetic etiology (e.g., perinatal hypoxic-ischemic injury, kernicterus, history of severe head trauma or central nervous system infection).