Pattern of skeletal malformations produced by Dominant hemimelia (Dh).

ABSTRACT

The hindlimb malformations in adult mice heterozygous for the dominant gene Dominant hemimelia (Dh) and +/+ littermates were characterized in skeletons 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 proximal portion. Although tibial hemimelia has been well documented in Dh mice, this study demonstrated a distinctive pattern of shortening of the tibia. 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 from mild to complete absence. The hindlimb malformation of Dh/+ mice occurred in association with a reduced number (five) of lumbar vertebrae. The interrelationship of the hindlimb malformations and the reduction in the vertebral number suggests a relationship between the development of the axial skeleton and the abnormal limb.