The karyotype of my cousin shows two barr bodies per cell. what condition might he have?

Trisomy-x: According to lyon hypothesis, mammalian species with multiple x chromosomes will have all x's inactivated except one; normally women have xx genotype thus has only one inactivated x ( barr body), men have xy thus has no inactivated x ( no barr body), your cousin most likely has a karyotype of 47, xxx, thus two barr bodies, so called " super woman", most are normal but a few may have problems.

It depends on the : This depends on the clincial setting, and number ofthe number of X chromosomes. It is an inactive X chromosome Women with two X chromosomes have one. Barr Body and men have no Barr bodies. It is one fewer than the number on X chromasome. So your cousin has 3 X chromosomes and two Barr bodies. This depends on her physician's clincal evaluation.