Mice lacking SDC1 are viable and fertile.34 Their phenotype, when stressed, reveals tissue-specific gain and loss of function attributes28 that have advanced our understanding of numerous complex pathologies including cardiovascular disease,74, –76 inflammatory conditions,77, –79 cancer,80, –82 and wound healing.29,34,83 The SDC1-null mouse is used here to study PNS reinnervation using corneal injury models. This evidence concerns the gene SDC1 and cardiovascular disorder.