Bilateral Striatal Hypometabolism on FDG PET in a Patient With McLeod Syndrome

18 F-FDG PET scan performed on a 59-year-old man with progressive chorea, cognitive decline, peripheral neuropathy, and elevated creatine kinase revealed marked bilateral caudate and putamen hypometabolism. Huntington disease was suspected but HTT testing was negative. Whole-exome sequencing identified a hemizygous XK mutation (c.664C>T, p.(Arg222*)), confirming McLeod syndrome. This case highlights that bilateral striatal hypometabolism with peripheral involvement in addition to extrapyramidal symptoms should raise suspicion for McLeod syndrome.