Video 1_Case Report: McLeod syndrome caused by a nonsense variant c.484C > T (p.Gln162Ter) in the XK gene in a Chinese Han family.mp4

Examination showed generalized areflexia, markedly elevated creatine kinase, bilateral caudate head atrophy on brain MRI, and axonal sensorimotor polyneuropathy on nerve conduction velocity (NCV) testing, with chronic neurogenic changes on needle electromyography (EMG). Peripheral smear revealed acanthocytosis in more than 60% of red blood cells, and serologic testing demonstrated markedly reduced reactivity with anti-Kell (K) and anti-Cellano (k) antibodies, suggesting reduced or absent Kx antigen and supporting a McLeod phenotype; whole-exome sequencing identified a hemizygous XK variant c.484C>T in the proband, and his asymptomatic daughter was heterozygous.

The diagnosis of McLeod syndrome was established, and supportive management was recommended; at telephone follow-up, hyperkinetic movements persisted and symptomatic medication had not yet been initiated because of concerns about adverse effects.</p>Conclusion<p>This family broadens the ethnic and clinical spectrum associated with the XK c.484C > T (p.Gln162Ter) variant and highlights the value of integrating acanthocyte assessment, McLeod blood group phenotyping, and genetic sequencing in the evaluation of males with hyperkinetic movements, peripheral neuropathy, and hyperCKemia to enable earlier diagnosis of MLS.</p>