POLD1 and mandibular hypoplasia-deafness-progeroid syndrome: Constitutional heterozygous POLD1 pathogenic variants that impair the polymerase (replicative) activity of Polδ (dominant negative effect), cause an autosomal dominant progeroid syndrome called MDPL (MIM# 615381), characterized by mandibular hypoplasia, deafness, progeroid features, and lipodystrophy [36, 37].