Clinical Presentation of the Longest Reported Living Individual With Bent Bone Dysplasia— <i>FGFR2</i> ‐Related

The FGFR2 gene, encoding the FGFR2 protein, plays a crucial role in embryonic cell development, particularly in bone tissue. Bent Bone Dysplasia (BBD), FGFR2-related (MIM# 614592), is a rare severe skeletal dysplasia characterized by craniofacial differences, reduced bone mineral density, and bowed long bones. Only 14 individuals have been reported, of which the majority died prenatally or neonatally. We report the clinical trajectory of a 4-year-old male with BBD, FGFR2-related (FGFR2, c.1141T>G), who initially presented neonatally with respiratory insufficiency requiring intubation, facial dysmorphism, and skeletal differences. He is able to walk, is interactive, has a tracheostomy for mechanical ventilation at night and a gastrostomy tube, and continues to make steady developmental progress. He is currently the longest reported living individual and with BBD, FGFR2-related in the literature to date. Our findings suggest that BBD, FGFR2-related is not definitively lethal perinatally. While the risk for complications and early postnatal death remains high, as demonstrated in previous literature, survival beyond the early postnatal period is possible. This report broadens the known postnatal developmental and medical trajectory of BBD, FGFR2-related, which is crucial for providing comprehensive genetic counseling.