pentasomy X
... that pentasomy X, in which a girl or woman has five X chromosomes, is sometimes mistaken for Down syndrome?
... that <b id="mwByk"><a href="./Pentasomy_X" id="mwByo" rel="mw:WikiLink" title="Pentasomy X">pentasomy<span id="mwBys" typeof="mw:Entity"> </span>X</a></b>, in which a girl or woman has five X<span id="mwByw" typeof="mw:Entity"> </span>chromosomes, is sometimes mistaken for <a href="./Down_syndrome" id="mwBy0" rel="mw:WikiLink" title="Down syndrome">Down syndrome</a>?