<unk>  syndrome (also called tetrasomy X, quadruple X, or<unk>  is a rare chromosomal disorder caused by the presence of four X chromosomes instead of two X chromosomes, which are normally found in females. This condition occurs only in females, as there are no Y chromosomes present. Tetrasomy X was first described in 1961, and since then approximately 100 cases have been reported worldwide. Approximately 60 females have been described in medical literature with this condition.
48, XXXX
49, XXXXX
48, XXYY
Trisomy 16
Trisomy 9
Trisomy 22
Tris
XX gonadal dysgenesis