Boomerang dysplasia is a lethal bone disorder characterized by bones malformed into a boomerang shape, especially in the arms and legs. It is caused by mutations in the FLNB gene, which regulates bone development. These mutations disrupt communication between cells and lead to abnormal bone and cartilage growth. Affected infants typically die in early infancy from complications of systemic bone malformations such as an underdeveloped rib cage and lungs.