Case Report and literature review: Delayed diagnosis of ARCL1B due to a newly reported homozygous mutation c.464A>C p. (Tyr155Ser) in the

Background: Autosomal recessive cutis laxa type 1B (ARCL1B) is an extremely rare disease characterized by severe systemic connective tissue abnormalities, including cutis laxa, aneurysm and fragility of blood vessels, birth fractures and emphysema. The severity of this disease ranges from perinatal death to manifestations compatible with survival. To date, no cases have been reported in the Chinese population. Due to its rarity, the disease is susceptible to misdiagnosis or missed diagnosis by clinicians. By presenting this case and reviewing the relevant literature, the aim is to enhance clinicians' awareness and vigilance in diagnosing this disease. Case presentation: We report a 7-month-old Chinese male infant who initially presented with severe respiratory infection, respiratory failure, and heart failure, and was misdiagnosed with Takayasu arteritis. Despite treatment, his condition did not improve. Due to the features of vascular malformations, developmental delay, and early onset of the disease, whole exome sequencing (WES) was performed, results revealed a homozygous mutation c.464A>C in exon 5 on the Conclusion: The