McLeod syndrome is a rare X-linked hematologic and neuromuscular disorder 
manifested by chorea, myopathy, cardiomyopathy, areflexia, hyperCKemia, and 
acanthocytosis. Only four mutations have been reported in the gene responsible 
for McLeod syndrome. We report a novel gene mutation in a Japanese family. 
Direct sequencing of the PCR-amplified genomic DNA revealed the mutation was a 
single C-nucleotide insertion at codon 151 in exon 2 of the XK gene, which 
resulted in a 3'-frameshift. Study of family members revealed that the patient's 
mother was a manifesting carrier heterozygous for this mutation.