IGSF1 and acromegaly: More recently, IGSF1 has been sequenced in euthyroid patients with X-linked constitutional delay of growth and puberty, and individuals with gigantism or acromegaly, with no evidence for a primary causative role for genetic variation in IGSF1 in these disorders (Faucz et al. 2015, Joustra et al. 2015b).