GUCY1A1 and multiminicore myopathy: In addition, cortical microvessel density (vascular density/ mm2, 515.70 ± 15.53 versus 351.20 ± 80.69, <i>p</i> = 0.0022; area%, 0.83 ± 0.20 versus 0.44 ± 0.18, <i>p</i> = 0.0152) and average diameter (3.5mm versus 2.5mm) were significantly reduced in <i>Gucy1a3</i> <sup>-/-</sup>.<h4>Conclusion</h4>Under early adult (8-12 weeks) conditions, <i>GUCY1A3</i> deficiency did not produce detectable large‐artery stenosis typical of MMD.