However, in contrast to the profound effects on kidney anatomy when GRP170 levels were similarly reduced (25, 28), thyroid histology was largely unaffected: follicles did not appear to be stimulated (Figure 3A), the size of the follicular lumen was not decreased (Supplemental Figure 1A; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.191837DS1), actively dividing cells remained sparse (Supplemental Figure 1B), and there was no evidence of goiter development (Figure 3B). The gene discussed is HYOU1; the disease is goiter.