A genetic variation on chromosome 1q21.3–q32.1 and 9p24.3–p22.3 and in Hemicentin-1 (HMCN1), which contains several oestrogen-binding sites, was found in 1200 women, and it appeared to increase the susceptibility of developing PPD.4 Here, HMCN1 is linked to progressive pseudorheumatoid arthropathy of childhood.