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Reviewed September 2011
What is boomerang dysplasia?
Boomerang dysplasia is a disorder that affects the development of bones throughout the body. Affected individuals are born with inward- and upward-turning feet (clubfeet) and dislocations of the hips, knees, and elbows. Bones in the spine, rib cage, pelvis, and limbs may be underdeveloped or in some cases absent. As a result of the limb bone abnormalities, individuals with this condition have very short arms and legs. Pronounced bowing of the upper leg bones (femurs) gives them a "boomerang" shape.
Some individuals with boomerang dysplasia have a sac-like protrusion of the brain (encephalocele). They may also have an opening in the wall of the abdomen (an omphalocele) that allows the abdominal organs to protrude through the navel. Affected individuals typically have a distinctive nose that is broad with very small nostrils and an underdeveloped partition between the nostrils (septum).
Individuals with boomerang dysplasia typically have an underdeveloped rib cage that affects the development and functioning of the lungs. As a result, affected individuals are usually stillborn or die shortly after birth from respiratory failure.
How common is boomerang dysplasia?
Boomerang dysplasia is a rare disorder; its exact prevalence is unknown. Approximately 10 affected individuals have been identified.
What genes are related to boomerang dysplasia?
Mutations in the FLNB gene cause boomerang dysplasia. The FLNB gene provides instructions for making a protein called filamin B. This protein helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin B attaches (binds) to another protein called actin and helps the actin to form the branching network of filaments that makes up the cytoskeleton. It also links actin to many other proteins to perform various functions within the cell, including the cell signaling that helps determine how the cytoskeleton will change as tissues grow and take shape during development.
Filamin B is especially important in the development of the skeleton before birth. It is active (expressed) in the cell membranes of cartilage-forming cells (chondrocytes). Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone (a process called ossification), except for the cartilage that continues to cover and protect the ends of bones and is present in the nose, airways (trachea and bronchi), and external ears. Filamin B appears to be important for normal cell growth and division (proliferation) and maturation (differentiation) of chondrocytes and for the ossification of cartilage.
FLNB gene mutations that cause boomerang dysplasia change single protein building blocks (amino acids) in the filamin B protein or delete a small section of the protein sequence, resulting in an abnormal protein. This abnormal protein appears to have a new, atypical function that interferes with the proliferation or differentiation of chondrocytes, impairing ossification and leading to the signs and symptoms of boomerang dysplasia.
Read more about the FLNB gene.
How do people inherit boomerang dysplasia?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Almost all cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
Where can I find information about diagnosis or management of boomerang dysplasia?
These resources address the diagnosis or management of boomerang dysplasia and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about boomerang dysplasia?
You may find the following resources about boomerang dysplasia helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for boomerang dysplasia?
What if I still have specific questions about boomerang dysplasia?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding boomerang dysplasia?
acids ; actin ; atypical ; autosomal ; autosomal dominant ; bronchi ; cartilage ; cell ; cytoskeleton ; differentiation ; dysplasia ; expressed ; gene ; omphalocele ; ossification ; pelvis ; prevalence ; proliferation ; protein ; protein sequence ; respiratory ; septum ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (3 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.