Low VW Activity in Adolescent HMB

Blood sample will be drawn to assess the number of participants enrolled that have sequence variation in the von willebrand factor gene and other genes affecting bleeding, clotting and blood vessel biology.

"The subject's response to intranasal or intravenous desmopressin (DDAVP) challenge performed as part of standard of care will be recorded. The desmopressin is a drug that increases the clotting factor in blood to prevent bleeding.~Medical and family history including and not limited to age, diagnoses, race/ethnicity, lab values, HMB and low VWF activity diagnoses, and treatment history and outcome will also be recorded."

PBAC is a pictorial tool to assess menstrual blood loss. Study team will complete the PBAC assessment with each study participant evaluating and measure response to different treatments for menstrual blood loss in the clinic setting between those with VWD versus other bleeding disorders.

Study participants will complete the ISTH BAT assessment. The ISTH BAT is a questionnaire to aid in the standardized evaluation of the presence and severity of bleeding symptoms.