Our 25 years of experience in carrier diagnosis of hemophilia A (HA) and B (HB) in Mexican population comprises linkage analysis of intragenic F8/F9 neutral variants along with, in severe HA (SHA), detection of F8 int22h and int1h inversions. In symptomatic carriers (SCs) we explored Lyonization to explain their symtomatology. From a DNA-Bank of 3,000 samples, intragenic restriction fragment length (RFLPs) and short tandem repeats (STRs) of F8/F9 genes were assessed by PCR-PAGE and GeneScan. In SHA patients, F8 inversions were detected by inverse shifting-PCR/ diagnostic and complementary tests. In SCs, we evaluated hemorrhagic symptoms, clotting FVIII/FIX and X-chromosome inactivation (XCI) patterns were assessed by HUMARA assay and the search of XIST promoter pathogenic variants. Informativeness of linkage analysis for HA carrier diagnosis with RFLP's/STR's increased to 74% and reached 80% with five RFLPs for HB. Combined Inv22/Inv1 diagnosed 113 possible carriers, three de novo Inv22-1, and confirmed 45 mothers as obligate or sporadic carriers. Among 21 SCs, four showed extreme skewed XCI pattern (80:20) but had normal karyotype and no C43G pathogenic variant in XIST promoter. Clotting FVIII/ FIX correlated with the active X in leukocytes. Our data integrate the largest comprehensive research worldwide on the molecular diagnosis of HA and HB carriers in terms of the number of studied and diagnosed cases, in addition to the genetic analysis in SCs. Intragenic RFLPs and STRs of F8/F9 genes along with F8 int22h/int1h inversions in SHA emerge as optimal variants for molecular diagnosis in Mexican population. In counseling SCs, inheritance of skewed X-inactivation should be considered.

Various inherited bleeding disorders deserve careful medical management due to their implications in women's health. In both hemophilia A and B, almost exclusively, males are affected while carrier females are generally asymptomatic. Nevertheless, carriers may present important bleeding tendencies, which can eventually constitute a serious threat to life, especially after surgery or postpartum. In addition, in rare but significant cases, some genetic mechanisms have been found to cause hemophilia in females. Aside from von Willebrand disease, which is the most widespread and better described hemorrhagic condition in women, platelet disorders and some rare clotting deficiencies cause a wide variety of mucocutaneous bleedings, menorrhagia, or postpartum bleeding, hence constituting an important health risk. A review of the genetic and pathophysiological aspects as well as main clinical complications of all these conditions will allow for preventive practices aimed at improving the quality of life of women with bleeding disorders.