The First Homozygous Family for Factor II G20210A Mutation in Latin America

Abstract number: P1266

Cadavid^1,2 AP, Cardona^3,4 H, Cardona-Maya^1,2 W, Román¹ A, Alvarez¹ L, Castaneda^1,2 SA, Martínez³ J, Torres¹ JD, Tobón¹ LI, Bedoya^1,3 G

^{1,2 1,3 3,4 1,21}Grupo de Estudio Trombosis, Universidad de Antioquia, A.A. 1226 Medellín-Colombia-SA ¹¹Grupo de Estudio Trombosis, Universidad de Antioquia, A.A. 1226 Medellín-Colombia-SA ³³Grupo GENMOL, Universidad de Antioquia, A.A. 1226 Medellín-Colombia-SA

The factor II G20210A (FII G20210A) mutation is known as a risk factor for arterial and venous thrombosis. The prevalence of this mutation is higher in Spanish populations (2.6–6.5%) than Caucasian populations from Northern Europe (0.7–4.0%). However, the prevalence of this mutation in Latin America is unknown. A study was conducted to assess the FII G20210A mutation influence on FII plasma levels and venous thrombosis in the first Latin American family including homozygous individuals for the FII 20210A mutated allele. Four generations of this Colombian family are described. The genotypes were determined by PCR-RFLP, and FII levels were quantified by coagulometric assay using FII deficient plasma and sisplastin excel. The proband is a 32-year-old man who developed unilateral thrombosis of iliac, femoral, and popliteal veins, concomitant with pulmonary embolism. This patient was found to be homozygous for the FII mutation. We studied the parents, five siblings, the maternal grandparents and two nephews of the proband. A total of 12 subjects were analyzed, 2/3 homozygous individuals had a history of venous thromboembolism (a sibling had history of iliofemoral venous thrombosis after initiating contraceptive therapy). Seven family members were heterozygous, and the 20210G wild-type allele was found in 2/12 subjects. FII G20210A heterozygous and 20210G homozygous carriers had a negative history of thrombosis. We quantified FII levels in the family and 20 healthy controls not carrying the mutation. Heterozygous family members had higher FII levels than controls (110.1 ± 18.6% and 92.4 ± 12.4%, respectively, P < 0.05). Factor II plasma levels in homozygous 20210A allele carriers (99.7 ± 30%) had no significant difference compared to the control group. This could be explained by anticoagulant therapy prescribed in two patients of the homozygous group. In this family, FII genotypes seemed to influence FII levels and 2/3 homozygous individuals had clinical manifestations. Support: UdeA-Colciencias.