 Foals with Lethal White Syndrome invariably die of colic within 72 hours, and are usually humanely euthanized.Carriers of the gene, who are healthy and normal, can be identified by a DNA test.While carriers often exhibit the "frame overo" pattern, this is not a dispositive trait and testing is necessary, as the pattern can appear in a minimal form as normal white markings or be masked by other white spotting genes.