FKRP (fukutin related protein) functions as a glycosyltransferase that catalyzes the transfer of ribitol 5-phosphate from CDP-L-ribitol to phosphorylated O-mannosyl trisaccharides on alpha-dystroglycan, representing the second step in forming ribose 5-phosphate tandem repeats essential for dystroglycan's ligand-binding capacity 1234. This post-translational modification is crucial for proper dystroglycan glycosylation and muscle membrane stability. FKRP mutations cause dystroglycanopathies, a heterogeneous group of muscular dystrophies ranging from severe congenital forms with brain and eye anomalies to milder limb-girdle muscular dystrophy (LGMD2I/LGMDR9) 56. In large cohorts, FKRP mutations account for approximately 9% of LGMD cases and represent the most frequent single cause of α-dystroglycanopathy 56. Patients typically present with proximal muscle weakness, with some mutations like c.919T>A causing severe phenotypes with early respiratory failure and loss of ambulation before age 20 7. Clinical manifestations can include cardiac abnormalities and respiratory complications requiring ventilatory support 8. The severity varies significantly based on specific mutations, with FKRP patients generally having milder phenotypes compared to other dystroglycanopathy subtypes 6.