DNA polymerase delta, whose catalytic subunit is encoded by POLD1, is responsible for lagging strand DNA synthesis during DNA replication1. It achieves this with high fidelity due to its intrinsic 3′ to 5′ exonuclease activity, which confers proofreading ability. Missense mutations in the exonuclease domain of POLD1 have recently been shown to predispose to colorectal and endometrial cancer2. Here we report a recurring heterozygous single amino acid deletion at the polymerase active site of POLD1 that abolishes DNA polymerase activity but only mildly impairs 3′ to 5′ exonuclease activity. This mutation causes a distinct multisystem disorder that includes subcutaneous lipodystrophy, deafness, mandibular hypoplasia and hypogonadism in males. This suggests that perturbation of function of the ubiquitously expressed POLD1 polymerase has surprisingly tissue-specific effects in man, and argues for an important role for POLD1 function in adipose tissue homeostasis.

Graphical AbstractHighlights d LincGET is asymmetrically expressed in the nucleus of twoto four-cell mouse embryos d LincGET overexpression biases blastomere fate toward inner cell mass (ICM) d LincGET physically binds to CARM1 d LincGET/CARM1 activates ICM-specific genes In BriefAn endogenous retrovirus-associated nuclear long noncoding RNA biases cell fate in mouse two-cell embryos.