http://en.m.wikipedia.org/wiki/XXXXX_syndrome

49, XXXXX

Where the female has 3 extra X chromosomes.

Growth and development

XXXXX syndrome causes mental, growth, and motor retardation. There is occasional delayed puberty. Behavior and performance is affected by opisthotonoid posture. Recent observations have indicated an average of a 10 to 15 IQ point decrease for each extra X chromosome. Thus, the average IQ of XXXXX individuals tends to be between 55 and 70.[1]

There are other types of "super females" and "super males" quite interesting to read about.

http://en.m.wikipedia.org/wiki/XXXX_syndrome

http://en.m.wikipedia.org/wiki/Triple_X_syndrome

http://en.m.wikipedia.org/wiki/XYY_syndrome

http://en.m.wikipedia.org/wiki/Turner_syndrome

http://en.m.wikipedia.org/wiki/Klinefelter_syndrome

http://en.m.wikipedia.org/wiki/XXYY_syndrome