Nebulin (NEB) is a giant sarcomeric protein of 183 exons that plays a critical role in muscle structural integrity and thin filament regulation. The protein binds and stabilizes F-actin within the Z-disc and is involved in regulating actin filament length during cardiac and skeletal muscle development 1. Structurally, NEB maintains sarcomeric organization and the myofibrillar membrane system by functioning as a key component of thin filament assembly 1. Pathogenic NEB variants cause nemaline myopathy (NM), the most common congenital myopathy, inherited in an autosomal recessive pattern 2. Over 200 disease-causing variants have been identified across NEB's 159 affected families, with recessive mutations representing the major genetic cause of NM 2. Additionally, NEB mutations associate with related myopathies including core-rod myopathy and distal myopathies, expanding the clinical phenotypic spectrum beyond classical nemaline presentations 23. Notably, nebulin tolerates substantial amino acid sequence variation, with pathogenic variants comprising only ~7% of coding variants identified in databases, explaining the relative rarity of NEB-associated disorders despite the gene's massive size 2. Clinically, NEB diagnosis historically relied on short-read sequencing with limited sensitivity in repetitive regions; however, long-read sequencing technologies (PacBio and Oxford nanopore) have significantly improved variant detection and diagnostic accuracy 4. Genotype-phenotype correlations in NEB disease remain challenging to establish reliably, complicating clinical prediction 2.