We extracted lists of genes from publications reporting SNP or loci and mutations involved either in CH (Porcu et al., 2013; Medici et al., 2015, 2017; Taylor et al., 2015; Kuś et al., 2020), or in variations in TSH and/or T4 levels, and from publications describing transcriptomics of adult (Vitale et al., 2017) or embryonic (Gerrard et al., 2016) thyroids. The gene discussed is CD4; the disease is cyclic hematopoiesis.