A number of genome-wide association studies (GWASs) of TD have been conducted (Aberg et al., 2010; Greenbaum et al., 2010; Syu et al., 2010), leading to a number of novel candidate genes, including the Perlecan-coding gene HSPG2 (also known as Heparan Sulfate Proteoglycan 2; HGNC ID: 5273; at 1p36.12). Here, HSPG2 is linked to thanatophoric dysplasia.