MASAC Makes Recommendation for Genotyping

by Janet Brewer, M.Ed

On July 6, 2022, the NHF Board of Directors approved NHF’s Medical and Scientific Advisory Council’s Document #247 Recommendations on Genotyping for Persons with Hemophilia.

From 2012-2018, My Life Our Future a collaborative partnership between the American Thrombosis and Hemostasis Network, Bioverativ (now Sanofi), Bloodworks and NHF with the generous support of more than 11,000 people with Hemophilia A and B to create a genotypic and phenotypic repository to advance the research and care for those affected by these rare disorders. In addition, at risk female relatives were included in this initiative from 2013-2017.

We learned much from this repository already that reflects

• <98% of those with hemophilia A/B have identified DNA changes in their factor gene

• Some individuals may have more than one DNA change

• More than one genotype may be detected in different affected family members

• In those born female at birth, as suspected, genotype is the most reliable method of diagnosis

In light of this information, MASAC document #273 recommends

• Individuals with hemophilia A or B undergo genotyping

• Affected male relatives (or individuals with a single X chromosome) undergo genotyping

• Females with more than one X chromosome at risk of inherited hemophilia-causing genetic change undergo genotyping REGARDLESS of FVIII or FIX levels

• Genotyping should be performed in a laboratory with experience in hemophilia genetics and results interpretation

This is an encouraging recommendation that could help advance care, treatment and predictors of birth planning, individualization of product types, inhibitor risk, and more. With this recommendation there is also the hope that it will be expanded to other factor disorders where levels do not always correlate with bleeding symptoms, such as in FVII deficiency.

ATHN (Source) https://athn.org/what-we-do/national-projects/ mlof-research-repository.html

MASAC #273 recommendations https://www.hemophilia.org/healthcare-professionals/ guidelines-on-care/masac-documents/masac-document-273recommendations-on-genotyping-for-persons-with-hemophilia