DUOX2 and Hashimoto thyroiditis: One mother had a mildly subnormal fT4 level that spontaneously normalized without treatment (case 6, DUOX2 p.R764W heterozygote) and one mother (case 25, DUOXA2 p.L204P heterozygote) subsequently developed non-autoimmune hypothyroidism, for which she remains on LT4 treatment.