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

## TL;DR

This paper presents a case of cerebrotendinous xanthomatosis, a rare genetic disorder, highlighting its diagnostic challenges and the importance of early recognition.

## Contribution

The paper contributes a detailed case report of CTX with genetic confirmation and discusses the diagnostic difficulties associated with this ultra-rare disorder.

## Key findings

- A 37-year-old male was diagnosed with CTX based on clinical features and genetic testing.
- The patient exhibited symptoms including muscle weakness, cataracts, cognitive decline, and tendon xanthomas.
- The case highlights the need for increased awareness to improve outcomes for rare neurogenetic disorders.

## Abstract

Background and Clinical Significance: Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder caused by mutations in the CYP27A1 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. Case Presentation: 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 CYP27A1 gene. Despite the unavailability of chenodeoxycholic acid (CDCA) therapy in Bulgaria, symptomatic management was provided. Conclusions: 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.