International Mammalian Genome Society

logo18th International Mouse Genome Conference

17-22 October 2004, Seattle, USA


Mori N 1, Kuwamura M 2, Kinoshita A 2, Okumoto M 1, Yamate J 2

1 Research Institute for Advanced Science & Technology, Osaka Prefecture University, Osaka, Japan, 2 Laboratory of Veterinary Pathology, Graduate School of Agriculture & Biological Sciences, Osaka Prefecture University, Osaka, Japan

A novel mouse mutation hemorrhagic hydrocephalus (hhy) in the BALB/c background was found at the Osaka Prefecture University in 2000. The hhy gene was inherited in an autosomal recessive manner and the hhy homozygous animals developed hydrocephalus with dilatation of lateral ventricles during post-natal and adult ages. Pathological examination detected mutants with mildly dilated ventricles among normal appearing siblings. Multiple hemorrhages were frequently seen in the meninges as well as throughout the brain parenchyma, but in other viscera of the animals affected by hydrocephalus. The hhy mutants showed neither macroscopic brain malformations nor causative stenoses of the ventricular system. Subcortical heterotopia, a sign of defective neuronal migration, was observed in all of the mutants. To assign the hhy locus, animals heterozygous for the hhy mutation (hhy/+) were mated with STS mice and the (hhy/+)F1 daughters were backcrossed to the hhy/+ males. Genome-wide screening using microsatellite markers identified the region carrying homozygous BALB/c allele on chromosome 12 in 12/12 (100%) affected animals arising in the crosse, which were pathologically diagnosed as hydrocephalus with ventricular dilatation. Linkage was confirmed in other cross. Our study showed that the hhy mutant might be a useful animal model for the study of neuronal abnormalities.

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