bent bone dysplasia syndrome 1

Bent bone dysplasia syndrome 1 is a skeletal dysplasia characterized by significant abnormalities in bone formation and structure. The condition is caused by pathogenic variants in the FGFR2 gene and is inherited in an autosomal dominant pattern, meaning that a single altered copy of the gene is sufficient to cause the disorder. It presents at or around birth with a constellation of skeletal findings and is extremely rare, affecting fewer than 1 in 1,000,000 individuals. Although the condition is present from birth, the severity and combination of features can vary among affected individuals.

The clinical presentation of bent bone dysplasia syndrome 1 is marked by several characteristic skeletal and soft tissue features. Virtually all affected individuals exhibit short clavicles, decreased calvarial ossification, hypoplastic pubic bones, abnormally large globes, bent long bones, hypertelorism, clitoral hypertrophy, and hirsutism. In addition, some patients may also have features such as coronal craniosynostosis or a natal tooth, and a smaller subset may present with hepatosplenomegaly. Not all individuals experience every feature, and the severity of these findings can vary considerably.

This condition is caused by pathogenic variants in the FGFR2 gene, which plays a key role in bone development and cellular growth. As an autosomal dominant disorder, only one altered copy of FGFR2 is necessary to manifest the syndrome. This inheritance pattern means that an affected individual has a 50% chance of passing the variant on to their offspring, although the exact combination and severity of symptoms can differ even among members of the same family due to variable expressivity.

Currently, management of bent bone dysplasia syndrome 1 focuses on supportive care and symptom management, as no treatments have been specifically approved for this condition. Care is tailored to the individual and typically involves a multidisciplinary team to address the various skeletal and soft tissue manifestations that may impact health. Recommendations often include orthopedic monitoring, physiotherapy, and other supportive interventions as needed, and genetic counseling is advised so that families can fully understand the inheritance pattern and implications for future family planning. Patients should discuss treatment options with their healthcare team to determine which supportive therapies are most appropriate for their situation.

The long-term outlook for individuals with bent bone dysplasia syndrome 1 is highly variable, with severity and complications differing from one person to another. With current standards of care, many individuals receive supportive treatments that help manage symptoms and improve quality of life over time. Outcomes described in medical literature continue to evolve as standards of care improve, and families are encouraged to seek guidance from genetic counselors and specialists experienced with skeletal dysplasias for personalized information and ongoing support.