Chinese identical twins with cerebrotendinous xanthomatosis: A family report and literature review.

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder of cholesterol metabolism, characterised by childhood-onset diarrhoea, juvenile cataracts, tendon xanthomas, and progressive neuropsychiatric symptoms. CTX is caused by mutations in the sterol 27-hydroxylase gene (CYP27A1) and sterol 27-hydroxylase deficiency. CTX is particularly rare in the Chinese population; to the best of our knowledge, this is the first report of identical twins with CTX in China. The present study also includes a review of the literature on the clinical presentation, imaging findings, and genetic results in identical twins and triplets with CTX. Our twin patients carried a homozygous transition mutation in intron 7 and displayed clinical manifestations of atypical parkinsonism and cognitive impairment; furthermore, they exhibited different phenotypes, which may be attributed to lifestyle differences. Early diagnosis and treatment are crucial to the prognosis of CTX, and genetic testing should be conducted to confirm the diagnosis.