LMOD1 was initially identified as a 64-kDa autoantigen in an expression screen with sera from patients with Hashimoto’s thyroiditis. Recently immunohistochemistry and immunoblotting of LMOD1 demonstrated its highly restrictive pattern of expression in SMC lineages,like adult aorta, and bladder. LMOD1 is also shown to exhibit an embryonic and adult expression pattern. These data identify LMOD1 as a new SMC-restricted gene associated with the SMC differentiated phenotype.