Nucleotide repeats emerge as one of the most prolific classes of genetic variations. They have the propensity to in-crease in length across generations, and have been implicated in at least 65 known neurological/ neurodevelop-mental and neuromuscular conditions. Simultaneous analysis of all these nucleotide repeats is now possible through the cutting-edge methodologies recently developed that are the long-read sequencing and the optical genome mapping. Investigator propose to test these methodologies in patients carrying expansions in those repeats and to determine the capacity of these technics to detect novel repeats in patients with no genetic diagnosis yet.