Moreover, thyroidal ERAD deficiency exacerbates the hypothyroidism of TG+/cog heterozygotes (circulating T4 levels lower and TSH higher), further increases the induction of CHOP, and limits further growth of the thyroid gland (Figure 5) at least in part by blocking incremental thyrocyte proliferation (Supplemental Figure 3) — and most dramatically, yields patchy areas of whole-follicle death and collapse (Figure 6 and Supplemental Figure 4), which leads to infiltration of bone marrow–derived cells (Figure 7) that are predominantly macrophages (Figure 8). Here, CD4 is linked to hypothyroidism.