Interestingly, one proband (GSD2201) was initially diagnosed with Paget’s disease or progressive diaphyseal dysplasia; eventually, he was found to carry a heterozygous variant in TGFβ-2 gene (c.220A>C, p.T74P) that could lead to Loeys-Dietz syndrome 4 (LDS4). The gene discussed is TGFB2; the disease is Paget disease.