Mutations in the base excision repair gene MYH were recently implicated in recessive inheritance of colorectal adenomas and carcinomas.¹ The majority of patient specimens screened for MYH and described in published reports derive from the United Kingdom, where two missense variants—Y165C and G382D—are the most prevalent mutations in the white population.^2–5 The carrier frequency for these two mutations is approximately 2% in the British population.^1,4 Some additional mutations were detected at lower frequency in these patients. Two other protein truncating mutations—E466X and Y90X—have been found in individuals of Indian and Pakistani descent, respectively.^2,3 Finally, a mutation that deletes codon Glu-466 was reported to be prevalent in Italian patients.⁶ This evidence supports the view that additional mutations will be discovered showing differences in prevalence between ancestries.

We determined the mutation spectrum for MYH by direct DNA sequencing in 219 anonymous North American patient specimens found negative for APC mutations during clinical genetic testing for risk …