Resistance to activated protein C (APCR), in the majority of cases due to the point mutation Arg 506 Gln of the factor V gene, has emerged as the most important hereditary cause of venous thromboembolism. Using an activated thromboplastin time (aPTT) based method in the presence of APC together with a DNA technique based on the polymerase chain reaction, we investigated 37 children with venous (V: n=19) or arterial (A: n=18) thromboembolism and 196 age-matched healthy controls for the presence of this mutation. In the control group 10 children were detected to be heterozygous for the factor V Leiden mutation, indicating a prevalence of 5.1%. 10/19 children (52%) with venous thrombosis and 7/18 (38%) patients with arterial thromboembolism showed the common factor V gene mutation. Additional inherited coagulation disorders were found in 1/10 (V:10%) and 2/7 (A:28%) APC-resistant patients. Inherited coagulation disorders without APCR were diagnosed in 3/9 (V: 33%) and 2/11 (A:18%) children. Furthermore, we diagnosed exogenous risk factors in 6/10 (V: 60%) and 2/7 (A: 28%) children with thrombosis and APCR. These data are evidence that APCR combined with exogenous reasons may play an important role in the early manifestation of thromboembolism during infancy and childhood.
With the present study we can show for the first time that the embryonal MTHFR 677TT genotype is significantly associated with the development of structural congenital heart malformations during early pregnancy. It remains to be clarified, whether this genotype is at least a risk marker or a risk factor for structural congenital heart malformations.
While FV G1691A and prothrombin G20210 A mutations show no significant data in our study, lipoprotein (a) levels >30 mg/dl protein C deficiency, anticardiolipin antibodies and combined prothrombotic disorders seem to be important risk factors for manifestation of ischaemic strokes in children with underlying cardiac disorders.
Aims-To determine to what extent the Arg 506 to Gln point mutation in the factor V gene and further genetic factors of thrombophilia aVect the risk of porencephaly in neonates and infants. Methods-The Arg 506 to Gln mutation, factor V, protein C, protein S, antithrombin, antiphospholipid antibodies and lipoprotein (a) (Lp(a)) were retrospectively measured in neonates and children with porencephaly (n=24). Results-Genetic risk factors for thrombophilia were diagnosed in 16 of these 24 patients: heterozygous factor V Leiden (n=3); protein C deficiency type I (n=6); increased Lp (a) (n=3); and protein S type I deficiency (n=1). Three of the 16 infants had two genetic risk factors of thrombophilia: factor V Leiden mutation combined with increased familial Lp (a) was found in two, and factor V Leiden mutation with protein S deficiency type I in one. Conclusions-The findings indicate that deficiencies in the protein C anticoagulant pathway have an important role in the aetiology of congenital porencephaly. (Arch Dis Child Fetal Neonatal Ed 1998;78:F121-F124)
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