Congenital leukaemia after heavy abuse of permethrin during pregnancy.

A single case is described of congenital leukaemia with 11q23/MLL rearrangement in a preterm female newborn. Because of arachnophobia, the mother had heavily abused aerosolised permethrin, a widely used household insecticide. Permethrin is considered comparatively safe, but, in view of the mother's history, its potential to induce cleavage of the MLL gene in cell culture was tested. Incubation of the BV173 cell line with 50 micro M permethrin readily induced MLL cleavage.