Mice homozygous for this targeted mutation are viable and fertile, with no gross anatomical abnormalities. Endogenous transcripts are absent in skeletal muscle and testis. Homozygotes exhibit abnormal B-cell development, reduced survival, lymphadenopathy secondary to accumulation of plasma cells, splenomegaly, and accelerated thymic atrophy. Mutant mice do not exhibit any obvious features of Williams-Beuren syndrome (WBS). These mice may be useful in studies of hematopoietic/lymphoid development and function (including B-cell and T-cell development), plasma cell homeostasis, and the Wnt/frizzled signaling pathway.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for this strain. It should be noted that the phenotype could vary from that originally published. We will modify the strain description if necessary as published results become available. While the original publication (Ranheim et al 2005 Blood 105:2487-94) describes homozygous mutant mice on a 129 genetic background, the donating investigator reports that no differences in behavioral/cognitive, cardiovascular, or other phenotyping are observed in the C57BL/6J-backcrossed colonies from which The Jackson Laboratory obtained the mice (2006).
