SMAD6 and endemic goiter: A GRS for higher TSH specific to the activin receptor-like kinase (ALK) in cardiac myocytes pathway (Biocarta, including novel genes SMAD6, BMP4) showed associations with reduced risk of nontoxic nodular and multinodular goitre, and simple goitre, as well as raised heel bone mineral density, standing height and whole-body fat-free mass and reduced FEV1/FVC (Fig. 3a, Supplementary Data 10).