A spontaneous novel XK gene mutation in a patient with McLeod syndrome

A 29-year-old man with a history of elevated creatine kinase and necrotizin g myopathy was reviewed. Prominent red cell acanthocytosis in association w ith reduced Kell antigen expression was present, findings consistent with t he McLeod syndrome. Investigation of the patient's XK gene revealed a novel TGG- to-TAG transition at position 1023 in exon 3. This point mutation cre ates an in-frame stop codon (W314X), and predicts a truncated XK protein of 313 amino acids, compared with 444 amino acids in the normal XK protein. T he mutation was not identified in the patient's mother or sister indicating that this mutation was spontaneous.