Hydrocephalus

Hydrocephalus arises sporadically among various strains of rats, but may have a genetic basis in some popula­tions, such as WAG/Rig rats. Affected rats have a domed calvarium, with dilation of lateral ventricles and thin cerebral cortices. Rats with congenital hydrocephalus typically present with dehydration at weaning age, when they are no longer under the care of their mothers. Hydrocephalus, resulting from stenosis of the cerebral aqueduct, can be readily induced in newborn rats from dams that are deficient in vitamin B12.