An Ultra-Rare Disorder: Case Report on Cerebrotendinous Xanthomatosis.

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder caused by mutations in the gene, leading to impaired bile acid synthesis and systemic cholesterol deposition. The condition presents with a broad spectrum of symptoms affecting multiple organs and systems, including the eyes, central nervous system, tendons, and skeletal muscles. Due to its heterogeneous and often ambiguous clinical manifestations, CTX is frequently misdiagnosed or remains undiagnosed for years. : We report the case of a 37-year-old male who was admitted to our university hospital with a long-standing history of progressive muscle weakness in the arms and legs. His medical history revealed bilateral cataract surgery in childhood, cognitive decline, epilepsy, and bilateral round swellings of the Achilles tendons, suspected to be xanthomas. A clinical diagnosis of CTX was established, and sequencing analysis confirmed the presence of a homozygous pathogenic variant in the gene. Despite the unavailability of chenodeoxycholic acid (CDCA) therapy in Bulgaria, symptomatic management was provided. : This case underscores the diagnostic challenges associated with CTX and highlights the prolonged diagnostic journey faced by patients with rare neurogenetic disorders. It also emphasizes the need for increased awareness and early recognition of such conditions to improve patient outcomes.