Comment: What mutation does he carry?

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What mutation does he carry?

What mutation does he carry? I am heterozygous which means I carry 1 of each. If he's got only 1 then it's possible that only 1 parent carries at least 1 bad gene. If he has 2 bad genes then both parents carry at least 1 bad gene. So both my parents carry at least 1 bad gene.