Hydrocephalus with hop gait (hyh): a new mutation on chromosome 7 in the mouse.

Hydrocephalus with hop gait (hyh) is a new lethal recessive mouse mutation that arose in the C57BL/10J strain at The Jackson Laboratory. It has been mapped to the proximal end of Chromosome 7 close to the Gpi-1 locus. This homozygous mutant is characterized clinically by a domed head and a hopping gait observable at 2 weeks of age and death between 4 and 10 weeks of age. The affected mice have dilated lateral ventricles and a large third ventricular cyst, patent through narrowed rostral cerebral aqueduct, cystic caudal aqueduct and no communication of the aqueduct with the fourth ventricle. The cerebellum has a mild cortical malformation.