Asymptomatic factor VII deficiency in African Americans

Area of Science:

• Genetics
• Hematology
• Molecular Biology

Background:

• Factor VII (FVII) deficiency is often asymptomatic in African Americans.
• The genetic basis for FVII deficiency in this population remained largely uncharacterized.
• Accurate diagnosis is crucial for appropriate patient management and to prevent unnecessary transfusions.

Observation:

• Three unrelated African-American patients with FVII deficiency were studied.
• Clinical laboratory values indicated low FVII coagulant activity.
• Testing utilized both rabbit brain and human thromboplastin assays.

Findings:

• A specific G to A nucleotide change was identified as the cause of FVII deficiency.
• This mutation results in an arginine to glutamine substitution at amino acid position 304 of Factor VII.
• The identified mutation led to reduced FVII coagulant activity when using rabbit brain thromboplastin, but not human thromboplastin.

Implications:

• This genetic finding provides a molecular explanation for FVII deficiency in African Americans.
• Understanding the specific mutation aids hematology specialists in interpreting patient laboratory results.
• The findings can help prevent unnecessary transfusions by clarifying the cause of abnormal FVII activity.