CARASIL misdiagnosed as Multiple Sclerosis: first CARASIL case of Iran (ORP-03)

Background: Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a rare genetic condition linked to mutations in the HTRA1 gene, primarily affecting small blood vessels in the brain. Due to its rarity and overlapping clinical features with other vascular disorders, CARASIL is often underrecognized.
Case Presentation: This case series presents two siblings diagnosed with CARASIL caused by a novel homozygous mutation in the HTRA1 gene. The 27-year-old male exhibited sudden onset of right hemiparesis, significant alopecia, and chronic back pain, supported by MRI findings of extensive white matter hyperintensities. His 31-year-old sister experienced recurrent neurological symptoms including left hemiparesis and visual disturbances, alongside similar MRI abnormalities. Genetic testing confirmed the presence of the HTRA1 mutation in both patients, establishing their diagnosis of CARASIL. We also delve into the neuroimaging findings and genetic background supporting the diagnosis.
Conclusions: This report underscores the need for increased awareness of CARASIL, especially in patients presenting with unexplained neurological symptoms. Clinicians should consider genetic testing in families with a history of similar symptoms to facilitate early diagnosis and management of this rare condition.