Mutations in the genes encoding signal transducer and activator of transcription (STAT)5B (Kofoed et al, 2003), one of the proteins in the signaling cascade of the GHR, IGF‐1 (Woods et al, 1996), and IGF‐1R (Abuzzahab et al, 2003), were subsequently shown to result in pre‐ and postnatal growth retardation of varying degrees, while mutations in the ALS gene cause short stature that can be classified as mild (Domené et al, 2004). The gene discussed is IGF1; the disease is amyotrophic lateral sclerosis.