NCOA1 and Infertility: The genomic colocalization of OSR1 and NCOA1 together with the finding of uterine estrogen insensitivity in the affected sisters is coincident with a relationship between the OSR1 mutant and impaired endometrial biology in the context of sex steroid dysregulation in the FRT, particularly endometrial estrogen insensitivity and resultant uterine factor infertility.