Boomerang dysplasia
Lethal skeletal disorder with boomerang-shaped limb bones.
Boomerang dysplasia is a lethal form of osteochondrodysplasia, a skeletal disorder that causes malformations of both bone and cartilage. It is known for a characteristic congenital feature in which the bones of the arms and legs are malformed into the shape of a boomerang. Death usually occurs in early infancy due to complications arising from overwhelming systemic bone malformations.
Quick Facts
- Differential
- Larsen syndrome, Greenberg dysplasia, Spondylocarpotarsal synostosis syndrome
Facts from the source article.
Lore & Background
Boomerang dysplasia presents prenatally and neonatally with several prominent features found in other osteochondrodysplasias, though the 'boomerang' malformation seen in the long bones is the delineating factor. Featured symptoms include a lethal type of infantile dwarfism caused by systemic bone deformities, underossification in the limbs, spine and ilium, proliferation of multinucleated giant-cell chondrocytes, brachydactyly, and micromelia. The characteristic boomerang malformation presents intermittently among random absences of long bones throughout the skeleton; for example, one individual may have an absent radius and fibula with the boomerang formation in both ulnas and tibias, while another may present boomerang femora and an absent tibia.
Reader's Guide
Boomerang dysplasia is significant as a lethal osteochondrodysplasia that highlights the critical role of the Filamin B (FLNB) gene in skeletal development. FLNB is a cytoplasmic protein that regulates intracellular communication and signalling by cross-linking actin to allow direct communication between the cell membrane and cytoskeletal network, guiding proper skeletal development. Disruptions in this pathway, caused by FLNB mutations, result in the bone and cartilage abnormalities associated with the disorder. Chondrocytes, which have a role in bone development, are susceptible to these disruptions and either fail to undergo ossification or ossify incorrectly. Early journal reports suggested X-linked recessive inheritance, but it was later discovered that the disorder is caused by a sporadic genetic mutation fitting an autosomal dominant profile. Because those afflicted do not live beyond infancy, they cannot pass the gene to the next generation, making boomerang dysplasia a non-inherited autosomal dominant disorder. FLNB mutations are involved in a spectrum of lethal bone dysplasias, including atelosteogenesis type I, which is very similar and shares several overlapping symptoms.
Did You Know?
- Boomerang dysplasia is caused by mutations in the Filamin B (FLNB) gene.
- Boomerang dysplasia is not inherited because those afflicted do not live beyond infancy.
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