‘Protection of telomeres 1′ (POT1) binds to chromosome ends (known as telomeres) to shield them from excessive degradation or lengthening. Mutations in the POT1 gene create a protein that cannot bind to the telomere. A person with a POT1 mutation is more likely to develop certain types of cancer. Mutations were found in POT1 in two patients with a history of both cutaneous and uveal melanoma; these patients have significantly longer telomeres than healthy individuals of the same age. We propose that mutations in POT1 increase the risk of developing uveal melanoma, broadening the spectrum of tumours associated with mutations in this gene.   (By Vaishnavi Nathan, https://jmg.bmj.com/content/early/2020/09/08/jmedgenet-2020-107098 )