Stroke is a frequent complication in patients with sickle cell anemia. Recently, an increased prevalence of resistance to activated protein C (APCR) has been reported in patients with idiopathic thrombosis. The defect responsible for APCR is a point mutation in the factor V gene IFV Leiden which changes Arg at position 506 to Gln. The estimated frequency of FV Leiden varies from 2 to 5% in the white population with similar or lower frequency in the African American population. This study was undertaken to determine whether FV Leiden is a risk factor for strokes in children with HbSS. The FV Leiden mutation eliminates a restriction enzyme digestion site, yielding characteristic RFLP patterns for heterozygotes and homozygotes. Genomic DNA gDNA) was extracted from peripheral blood mononuclear cells. Polymerase chain reaction (PCR) was used to amplify a 206 bp fragment of the gDNA containing the mutated site, followed by Minl-1 digestion of the amplified product. The digests were run on 4% Nusieve agarose gels and visualized with ethidium bromide. The expected patterns were 3 bands of sizes 123, 47 and 36 bp's in patients with the normal FV gene; 4 bands of sizes 159, 123, 47, 36 bp's in heterozygotes with Leiden mutation and 2 bands of 159 and 47 b's in homozygotes with the Leiden mutation. Eighteen patients (ages 4 -21 years, median 9.5 years) with Hbss and stroke on chronic transfusion therapy were studied. All patients were African American. Factor V Leiden was not detected in any of the patients studied, suggesting that it probably does not contribute to development of stroke in HbSS. There is no information to disclose.
