Pattern of skeletal malformations produced by Dominant hemimelia (Dh)

The hindlimb malformations in adult mice heterozygous for the dominant gene Dominant hemimelia (Dh) and +/+ littermates were characterized in skeleton s that had been fixed, stained, and cleared. When the tibia was shortened, the deficiency was always an absence of the distal portion, and never the p roximal portion. Although tibial hemimelia has been well documented in Dh m ice, this study demonstrated a distinctive pattern of shortening of the tib ia. Measurements of the length of the tibia (relative to the length of the humerus) showed only three patterns of shortening of the tibia (i.e., mild, moderate, and severe), rather than a continuous spectrum of shortening fro m mild to complete absence. The hindlimb malformation of Dh/+ mice occurred in association with a reduced number (five) of lumbar vertebrae. The inter relationship of the hindlimb malformations and the reduction in the vertebr al number suggests a relationship between the development of the axial skel eton and the abnormal limb. (C) 1999 Wiley-Liss, Inc.