Following the discovery of predisposing germline mutations in the POT1 gene, another shelterin complex component, for cutaneous malignant melanoma (CMM) [38,39,44], three families with germline variants in TERF2IP, including the nonsense mutation p.(R364Ter) and mutations co-segregating with cutaneous melanoma, were identified. Here, POT1 is linked to familial congenital mirror movements.