Apolipoprotein E polymorphisms and severity of cerebral palsy: a cross‐sectional study in 255 children in Norway

Aim The aim of this study was to examine whether the presence of the apolipoprotein E (ApoE) allele APOEε4 is associated with less severe manifestations of cerebral palsy (CP), consistent with the suggested beneficial effect of this allele on neurodevelopment in children. Method ApoE genotyping was performed on buccal epithelial cells from 255 children (141 males 114 females; mean age 12y, SD 2y 3mo, range 9–17y) recorded in the Cerebral Palsy Register of Norway. The main outcome measure of CP severity was the Gross Motor Function Classification System (GMFCS). Secondary outcome measures were fine motor function, epilepsy, and the need for gastrostomy tube feeding (GTF). Results There was no association between the APOEε4 genotype and GMFCS levels (odds ratio [OR] 1.15; 95% confidence interval [CI] 0.66–1.99). However, the APOEε4 genotype was more often present among children with epilepsy (OR 2.2; 95% CI 1.1–4.2) and/or receiving GTF (OR 2.7; 95% CI 1.1–6.6). Among children with unilateral CP, the presence of APOEε4 was associated with more severe fine motor impairment (OR 2.6; 95% CI 1.3–6.9). Interpretation Our main hypothesis that APOEε4 would have a protective effect on neurodevelopment was not supported. Instead, subgroup analyses suggested an adverse effect of the APOEε4 genotype on the developing brain after injury. This article is commented on by O'Callaghan on pages 302–303 of this issue.