Individuals with 48, XXXY or 49,XXXXY are called variants of Klinefelter Syndrome by P.J.Russell,2010 (i Genetics). But I read a paper published in 2011 titled: 48,XXYY, 48,XXXY and 49,XXXXY syndromes: not just variants of Klinefelter syndrome. My question is why the physiological condition of 48,XXXY/ 49,XXXXY individuals considered syndromes and variants of Klinefelter syndrome at the same time? Being a variant of Klinefelter syndrome must mean that it has symptoms similar to that of Klinefelter Synderome (actually a level higher in case of severeity) but again why is it called 48, XXXY Syndrome. To be called a syndrome it must be also have distinct symptoms (I presume).