The sash mutation results in an embryonic deficit and eventual abolishment of mast cells soon after birth. There is also a deficit of melanocytes and interstitial cells in these mice. Reduced numbers of melanocytes results in some hearing impairment in homozygotes. The KitW-sh mutation is a inversion in regulatory elements upstream of the c-kit element. Homozygotes are white with black eyes and some pigment around the ears. Heterozygotes are black with a white sash at the midline. The mice are fertile and not anemic. 2012: Findings of altered immune responses as a result of mast cell deficit in these mice include: &nbsp;&nbsp;&nbsp;&bull; &nbsp; heightened susceptibility to vaccinia virus skin infection; &nbsp;&nbsp;&nbsp;&bull; &nbsp; earlier and more severe experimental autoimmune encephalomyelitis disease (a model of multiple sclerosis) with extensive demyelination and inflammation in the CNS; &nbsp;&nbsp;&nbsp;&bull; &nbsp; exacerbated dermatitis upon repeated oxazolone challenge when compared to their wild-type; &nbsp;&nbsp;&nbsp;&bull; &nbsp; Ultra violet exposure in these mice does not induce immune suppression, as it does in wild type mice; &nbsp;&nbsp;&nbsp;&bull; &nbsp; lower serum IgE levels compared with wild-type mice under steady-state conditions and after N. brasiliensis (hookworm) infection; &nbsp;&nbsp;&nbsp;&bull; &nbsp; failure to elicit histamine release or contractile responses in trachea isolated from ovalbumin sensitized mast cell-deficient mice; &nbsp;&nbsp;&nbsp;&bull; &nbsp; development of 50% more adenomas than littermate controls and with tumors being 33% larger in KitW-sh mice; &nbsp;&nbsp;&nbsp;&bull; &nbsp; increased resistance to bacterial lipopolysaccharide injection; &nbsp;&nbsp;&nbsp;&bull; &nbsp; failure of ovalbumin sensitization to elicit histamine release or contractile responses in trachea isolated from sensitized KitW-sh mice.

A C57BL/6J congenic version of this strain made via SNP marker-assisted speed congenic protocol is available as Stock No. <a href="https://www.jax.org/strain/030764">030764</a> (all 140+ tested markers outside the Kit genomic region were C57BL/6J). 
 The spontaneous KitW-sh (or "sash") mutation affects melanoblast and mast cell survival, and may be useful in studying melanogenesis, hematopoiesis, gametogenesis and mast cell deficiency.

Typically mice are recovered in 12-16 weeks. Contact Customer Service to place an order or for more information.

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