47,XXY/48,XXXY/49,XXXXY mosaic with hydrocephaly: a case report and review of the literature.

Klinefelter's syndrome is a frequent genetic sexual alteration in males, associated with the 47,XXY aneuploidy. Several syndrome variants are caused by different X and Y polysomy and mosaicisms, including the 49,XXXXY condition described by some authors as Fraccaro's syndrome. Mosaics with three or more different chromosomal lines are very rare.