EPHX1 and brain neoplasm: Among children with a high-risk variant (RR or HR) for EPHX1 H139R, children whose mothers smoked 11 or more cigarettes per day were twice as likely to develop a childhood brain tumor as children of mothers who did not smoke (OR = 2.19; 95% CI: 0.72, 6.63), however, the number of children exposed to high levels of maternal smoking was low.