Diabetes (db), which occurred in an inbred strain of mouse, is inherited as a unit autosomal recessive and is characterized by a metabolic disturbance resembling diabetes mellitus in man. Abnormal deposition of fat at 3 to 4 weeks of age is followed shortly by hyperglycemia, polyuria, and glycosuria. Accompanying morphological changes in the islets of Langerhans suggest neogenesis to compensate for insulin depletion.

No abstract

Two mutant mice with deficient myelination are described. Quaking is a new autosomal recessive mutant mouse with marked tremor of the hindquarters. The mice eat, swim, breed, and nurse well even though the entire central nervous system is very deficient in myelin by histological and chemical criteria. Myelin formation is impaired; no destruction is seen. Peripheral nerves are myelinated. Jimpy, a known sex-linked mutation, has similar but more severe symptoms and similar pathology, with the additional feature of sudanophilic (nonpolar) lipid distributed in some white-matter tracts. Both mutants offer new opportunities for study of the formation and functions of myelin.

The "staggerer" mutant is recognized by its staggering gait, mild tremor, hypotonia, and small size. Symptoms develop during postnatal weeks 1 to 4 and remain stationary thereafter. The cerebellar cortex is grossly underdeveloped, with too few granule cells and unaligned Purkinje cells. Genetic linkage studies and neuropathological findings distinguish staggerer from other known mutants.

OBESITY, other than that occurring in yellow mice, is relatively rare in mice. The obese yellow animals attain weights up to 75 or 80 grams but the average weight is around 60 grams and then there is a decrease in weight as age increases.j In the summer of 1949 some very plump young mice were found in the V stock.j Others occurred shortly after that among offspring of these V stock animals that had been outcrossed to the fuzzy sock.