XYYY syndrome
... that XYYY syndrome, a chromosome abnormality in which a man has two extra Y chromosomes, has only been recorded twelve times?
... that <b id="mwBm4"><a href="./XYYY_syndrome" id="mwBm8" rel="mw:WikiLink" title="XYYY syndrome">XYYY syndrome</a></b>, a <a href="./Chromosome_abnormality" id="mwBnA" rel="mw:WikiLink" title="Chromosome abnormality">chromosome abnormality</a> in which a man has two extra Y chromosomes, has only been recorded twelve times?