A 16-year-old female presents with Primary Amenorrhea. Examination shows a Short Blind Vagina, with absent Uterus. The Next Investigation of choice is:

Ans. is a, i.e. KaryotypingRef: Jeffcoate 7th/ed, p198; CGDT 10th/ed, p931 Fig. 56-2A female presenting with absent uterus and short blind vagina:D/D's that should come to your mind are:Mullerian dysgenesis and Testicular feminizing syndrome (or male pseudohermaphroditism)PresentationMullerian AgenesisAndrogen InsensitivityInheritance patternSporadicX-linked recessiveKaryotype46XX46XYBreast developmentYesYesAxillary and pubic hairYesNoUterusNoNoGonadOvaryTestisTestosteroneFemale levelsMale levelsAssociated anomaliesYesNoSo, the best way to differentiate between the two is to do karyotyping or chromatin/barr body test, which comes positive (barr body present) in 46XX and negative (barr body absent) in case of 46XY Genotype.