Atypical presentations of RECQL4-related syndromes.

RECQL4-related syndromes are a group of rare cancer-predisposition syndromes caused by biallelic pathogenic/likely pathogenic variants (PV/LPV) in the DNA helicase gene, RECQL4. Genetic testing is typically prompted by the presence of one or more hallmark clinical features, and in the absence of such manifestations, diagnosis may be delayed or even missed. We describe five patients with biallelic germline mutations in RECQL4 who presented atypically, without the hallmark clinical manifestations of this syndrome. Three of these patients developed osteosarcoma, underscoring the importance of recognizing atypical presentations of Rothmund-Thomson syndrome (RTS) to allow for early awareness and surveillance for cancer.