The woman realizes that the voice is a manifestation of her disease and not a communication from aliens or spirits. Another gene studied by Walsh causes a second cortex, or abnormal layer of cells, under the normal cortex. Both genes occur on the so-called X chromosome. According to Walsh, women with mutant PH and DC genes have brains with a mosaic of normal and abnormal cells. Such women will have a shortage of sons and an excess of daughters, half of whom will have epilepsy.
Males are worse off.
Working at the Beth Israel Deaconess Medical Center with neurologists Joseph Gleeson and Kristina Allen, Walsh is close to cloning the DC gene. Using these clones, they can conduct experiments to determine exactly which mutations lead to these epilepsies and how. Walsh and his collaborators have been trying to get drug and biotechnology companies interested in designing new treatments as the location and function of different epilepsy genes become known. Walsh's lab is also making progress toward his other goal of studying epilepsy to gain insight into how normal brains develop and function. In PH epilepsy, brain cells don't leave the nursery where they're born.