Prenatal development of the grey lethal mouse. I. Teeth and jaws.

Osteopetrosis is a disease in which diffuse sclerosis of the entire skeleton results from an imbalance between the processes of bone formation and bone resorption. The grey lethal is the most severely affected of the three mouse mutants which have been described and its osteopetrosis is transmitted as a simple autosomal recessive gene. Affected mice develop a grey coat at 8-10 days of age and die before one month of age. Recently we (Hollinshead and Schneider, '73) reported that grey lethal mice could be identified at birth because the apex of their lower incisors lies anterior to the molar region in the mandible. In this study we show that it is possible to identify affected fetuses from day 18 of gestation using the same and other histologic criteria in examining their teeth.