Screening for inherited thrombophilia recommended for relatives of children with VTE

Issue: June 25, 2012

Relatives of pediatric patients with venous thromboembolism should be screened for inherited thrombophilia because they may be at a significantly increased risk for thromboembolism, according to study results.

The study was designed to determine how much influence inherited thrombophilia had on the risk for first symptomatic VTE in first-degree and second-degree family members of children who have VTE. Prior research has shown that inherited thrombophilia significantly increases the risk for a first VTE.

The researchers enrolled 206 consecutively admitted children aged 18 years or younger with newly diagnosed VTE between 1996 and 2010. In addition, 667 of these patients’ first-degree and second-degree relatives also were enrolled.

The family members underwent baseline and annual subsequent exams to document medical history and to evaluate previous or existing VTE. All participants were tested for inherited thrombophilia, specifically antithrombin, protein C, protein S, Factor V G1691A, and Factor II G20210A.

Ultimately, VTE occurred in 47 relatives, six of whom were aged younger than 18 years. Twenty-seven percent of relatives were found to have at least one inherited thrombophilia. Most patients had only a single defect, the most common of which was heterozygous Factor V G1691A.

Family members with inherited thrombophilia had a significantly increased risk for VTE compared with those without it (HR=7.6; 95% CI, 4.0-14.45). This risk was even higher among family members with antithrombin, protein C or protein S deficiency (HR=25.7; 95% CI, 12.2-54.2).

“Given the high absolute risk of VTE in relatives with protein C, protein S, and antithrombin deficiency, we suggest screening for these forms of hereditary thrombophilia in children with VTE and their relatives,” the researchers wrote.

For more information:

Holzhauer S. Blood. 2012;doi:10.1182/blood-2012-01-405514.