Endosteal hyperostosis, Worth type

Endosteal hyperostosis, Worth type (also known as Worth disease, autosomal dominant endosteal hyperostosis, or Worth syndrome) is a rare genetic skeletal disorder characterized by increased bone density due to excessive bone formation on the inner (endosteal) surfaces of bones. It is caused by gain-of-function mutations in the LRP5 gene (low-density lipoprotein receptor-related protein 5), which plays a critical role in the Wnt signaling pathway that regulates bone formation and remodeling. The condition primarily affects the skeletal system, leading to generalized osteosclerosis (abnormally dense bones) that can be detected on radiographic imaging. Key clinical features include a wide, deep mandible (jaw) with a squared appearance (torus palatinus may be present), thickening of the cranial vault and long bones, and increased cortical bone density throughout the skeleton. Despite the markedly increased bone density, individuals with Worth type endosteal hyperostosis are generally in good health and may be relatively asymptomatic. The dense bones are typically resistant to fractures. Some patients may experience cranial nerve compression due to narrowing of skull foramina, which can lead to facial palsy or other neurological symptoms, though this is uncommon. The condition is usually identified incidentally on X-rays or through family screening. There is no specific curative treatment for Worth disease. Management is primarily supportive and based on surveillance for potential complications, particularly cranial nerve entrapment. Surgical intervention may be considered in rare cases where bony overgrowth causes nerve compression or other functional impairment. The prognosis is generally favorable, as most affected individuals lead normal lives with normal life expectancy. Genetic counseling is recommended for affected families given the autosomal dominant inheritance pattern.

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