Editor—We read with interest the article by Ulrike et al.1 They diagnosed hereditary thrombophilia in seven out of 35 (20%) neonates investigated; the cerebral arteries were involved in seven of 79 (9%) of cases in the study. Tests were not available at the time of the study to detect resistance to activated protein C.

In another study of 37 children with venous and arterial thrombosis, 5.1% of a control group, 52% with venous thrombosis, and 38% with arterial thrombosis, had the factor V mutation associated with activated protein C resistance (APCR)).2 In this study cerebral artery thrombosis occurred in 14 neonates, suggesting that APCR and other defects of the protein C pathway may have a major …