Mice that are homozygous for the targeted mutation are viable, but sterile. A truncated mRNA transcript is detected during embryogenesis. Homozygotes exhibit ventralization of dorsal limb mesoderm tissues. The variable phenotype includes thickening of dorsal limb dermus, loss of dorsal hair on digits and abnormal or missing posterior distal digits. Abnormalities are more severe distally than proximally. Homozygous female mice have functioning ovaries, but are sterile due to abnormal development of the oviduct and uterus. Although homozygous male mice have normal spermatogenesis, Mullerian ducts do not regress resulting in blocked sperm passage. Mutant mice have reduced synapsin I levels and delayed synaptogenesis between cerebellar granule cells and mossy fiber neurons. This mutant mouse strain may be useful in studies related to dorsal-ventral and anterior-posterior patterning and axonal remodeling. The Jackson Laboratory 2024, used with permission.