LAUSR

A 57-year-old woman presented with a 20-year history of progressive lower extremity weakness, spasticity, and proprioception deficits. She was given a diagnosis of primary progressive multiple sclerosis at age 38. Her Achilles tendons were enlarged (figure 1). Brain MRI was normal. Spine MRI demonstrated T2-hyperintense signal involving the posterior and lateral columns (figure 2). Serum cholestanol level was elevated. CYP27A1 gene sequencing revealed 2 pathogenic variants, c.1183C>T(p.Arg395Cys) and c.410G>A(p.Arg137Gln), confirming the diagnosis of cerebrotendinous xanthomatosis (CTX). Spinal xanthomatosis is a rare variant of CTX presenting with progressive corticospinal and posterior column signs.1 Early treatment with chenodeoxycholic acid may improve outcomes.2