Inheritance of 'overshot' malocclusion in German shorthaired pointers

An abnormality of jaw development in the German shorthaired pointer which results in severe overshot is described. Its frequency of occurrence in a kennel where only phenotypically normal breeding stock were used was six/100 pups alive at three weeks. The abnormality was inherited in a manner consistent with the influence of a single autosomal recessive gene. The penetrance of the gene could possibly be masked in populations in which undershot jaw occurs.