Boomerang dysplasia | |
---|---|
Other names | Dwarfism with short, bowed, rigid limbs and characteristic facies |
Boomerang dysplasia has an autosomal dominant pattern of inheritance. | |
Specialty | Medical genetics |
Boomerang dysplasia is a lethal form of osteochondrodysplasia [1] known for a characteristic congenital feature in which bones of the arms and legs are malformed into the shape of a boomerang. [2] Death usually occurs in early infancy due to complications arising from overwhelming systemic bone malformations. [1]
Osteochondrodysplasias are skeletal disorders that cause malformations of both bone and cartilage.
Prenatal and neonatal diagnosis of boomerang dysplasia includes several prominent features found in other osteochondrodysplasias, though the "boomerang" malformation seen in the long bones is the delineating factor. [2]
Featured symptoms of boomerang dysplasia include: dwarfism [3] (a lethal type of infantile dwarfism caused by systemic bone deformities), [4] underossification (lack of bone formation) in the limbs, spine and ilium (pelvis); [1] proliferation of multinucleated giant-cell chondrocytes (cells that produce cartilage and play a role in skeletal development - chondrocytes of this type are rarely found in osteochondrodysplasias), [5] brachydactyly (shortened fingers) and micromelia (undersized, shortened bones). [2]
The characteristic "boomerang" malformation presents intermittently among random absences of long bones throughout the skeleton, in affected individuals. [3] [6] For example, one individual may have an absent radius and fibula, with the "boomerang" formation found in both ulnas and tibias. [6] Another patient may present "boomerang" femora, and an absent tibia. [3]
Mutations in the Filamin B (FLNB) gene cause boomerang dysplasia. [1] FLNB is a cytoplasmic protein that regulates intracellular communication and signalling by cross-linking the protein actin to allow direct communication between the cell membrane and cytoskeletal network, to control and guide proper skeletal development. [7] Disruptions in this pathway, caused by FLNB mutations, result in the bone and cartilage abnormalities associated with boomerang dysplasia.[ citation needed ]
Chondrocytes, which also have a role in bone development, are susceptible to these disruptions and either fail to undergo ossification, or ossify incorrectly. [1] [7]
FLNB mutations are involved in a spectrum of lethal bone dysplasias. One such disorder, atelosteogenesis type I, is very similar to boomerang dysplasia, and several symptoms of both often overlap. [8] [9]
Early journal reports of boomerang dysplasia suggested X-linked recessive inheritance, based on observation and family history. [3] It was later discovered, however, that the disorder is actually caused by a sporadic genetic mutation fitting an autosomal dominant genetic profile. [8]
Autosomal dominant inheritance indicates that the defective gene responsible for a disorder is located on an autosome, and only one copy of the gene is sufficient to cause the disorder, when inherited from a parent who has the disorder. [10]
Boomerang dysplasia, although an autosomal dominant disorder, [8] is not inherited because those afflicted do not live beyond infancy. [1] They cannot pass the gene to the next generation.[ citation needed ]
This section is empty. You can help by adding to it. (July 2017) |
This section is empty. You can help by adding to it. (July 2017) |
Weissenbacher–Zweymuller syndrome (WZS), also called Pierre-Robin syndrome with fetal chondrodysplasia, is an autosomal recessive congenital disorder, linked to mutations in the COL11A2 gene, which codes for the α2 strand of collagen type XI. It is a collagenopathy, types II and XI disorder. The condition was first characterized in 1964 by G. Weissenbacher and Ernst Zweymüller.
Otospondylomegaepiphyseal dysplasia (OSMED) is an autosomal recessive disorder of bone growth that results in skeletal abnormalities, severe hearing loss, and distinctive facial features. The name of the condition indicates that it affects hearing (oto-) and the bones of the spine (spondylo-), and enlarges the ends of bones (megaepiphyses).
Collagen, type II, alpha 1 , also known as COL2A1, is a human gene that provides instructions for the production of the pro-alpha1(II) chain of type II collagen.
Tyrosine-protein kinase transmembrane receptor ROR2, also known as neurotrophic tyrosine kinase, receptor-related 2, is a protein that in humans is encoded by the ROR2 gene located on position 9 of the long arm of chromosome 9. This protein is responsible for aspects of bone and cartilage growth. It is involved in Robinow syndrome and autosomal dominant brachydactyly type B. ROR2 is a member of the receptor tyrosine kinase-like orphan receptor (ROR) family.
An osteochondrodysplasia, or skeletal dysplasia, is a disorder of the development of bone and cartilage. Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia. Nonetheless, if taken collectively, genetic skeletal dysplasias or osteochondrodysplasias comprise a recognizable group of genetically determined disorders with generalized skeletal affection. These disorders lead to disproportionate short stature and bone abnormalities, particularly in the arms, legs, and spine. Skeletal dysplasia can result in marked functional limitation and even mortality.
Multiple epiphyseal dysplasia (MED), also known as Fairbank's disease, is a rare genetic disorder that affects the growing ends of bones. Long bones normally elongate by expansion of cartilage in the growth plate near their ends. As it expands outward from the growth plate, the cartilage mineralizes and hardens to become bone (ossification). In MED, this process is defective.
Pseudoachondroplasia is an inherited disorder of bone growth. It is a genetic autosomal dominant disorder. It is generally not discovered until 2–3 years of age, since growth is normal at first. Pseudoachondroplasia is usually first detected by a drop of linear growth in contrast to peers, a waddling gait or arising lower limb deformities.
Laminopathies are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear lamina. Since the first reports of laminopathies in the late 1990s, increased research efforts have started to uncover the vital role of nuclear envelope proteins in cell and tissue integrity in animals. Laminopathies are a group of degenerative diseases, other disorders associated with inner nuclear membrane proteins are known as nuclear envelopathies.
Filamin B, beta (FLNB), also known as Filamin B, beta , is a cytoplasmic protein which in humans is encoded by the FLNB gene.
Oculodentodigital syndrome is an extremely rare genetic condition that typically results in small eyes, underdeveloped teeth, and syndactyly and malformation of the fourth and fifth fingers. It is considered a kind of ectodermal dysplasia.
Keutel syndrome (KS) is a rare autosomal recessive genetic disorder characterized by abnormal diffuse cartilage calcification, hypoplasia of the mid-face, peripheral pulmonary stenosis, hearing loss, short distal phalanges (tips) of the fingers and mild mental retardation. Individuals with KS often present with peripheral pulmonary stenosis, brachytelephalangism, sloping forehead, midface hypoplasia, and receding chin. It is associated with abnormalities in the gene coding for matrix gla protein, MGP. Being an autosomal recessive disorder, it may be inherited from two unaffected, abnormal MGP-carrying parents. Thus, people who inherit two affected MGP alleles will likely inherit KS.
EEM syndrome is an autosomal recessive congenital malformation disorder affecting tissues associated with the ectoderm, and also the hands, feet and eyes.
Fibrochondrogenesis is a rare autosomal recessive form of osteochondrodysplasia, causing abnormal fibrous development of cartilage and related tissues.
Gerodermia osteodysplastica (GO) is a rare autosomal recessive connective tissue disorder included in the spectrum of cutis laxa syndromes.
Hydrops-ectopic calcification-moth-eaten skeletal dysplasia is a defect in cholesterol biosynthesis. Greenberg characterized the condition in 1988.
Lethal congenital contracture syndrome 1 (LCCS1), also called Multiple contracture syndrome, Finnish type, is an autosomal recessive genetic disorder characterized by total immobility of a fetus, detectable at around the 13th week of pregnancy. LCCS1 invariably leads to prenatal death before the 32nd gestational week. LCCS1 is one of 40 Finnish heritage diseases. It was first described in 1985 and since then, approximately 70 cases have been diagnosed.
Fryns syndrome is an autosomal recessive multiple congenital anomaly syndrome that is usually lethal in the neonatal period. Fryns (1987) reviewed the syndrome.
Eiken syndrome, also known as "Eiken skeletal dysplasia", is a rare autosomal bone dysplasia with a skeletal phenotype which has been described in a unique consanguineous family, where it segregates as a recessive trait. First described in 1985, the syndrome primarily affects the development of bones, leading to short stature, long limbs, and joint dislocations. Eiken syndrome is caused by mutations in the PTH1R gene, located on chromosome 3, and is involved in skeletal development.
Severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN) is a very rare genetic disorder. This disorder is one that affects bone growth and is characterized by skeletal, brain, and skin abnormalities. Those affected by the disorder are severely short in height and commonly possess shorter arms and legs. In addition, the bones of the legs are often bowed and the affected have smaller chests with shorter rib bones, along with curved collarbones. Other symptoms of the disorder include broad fingers and extra folds of skin on the arms and legs. Developmentally, many individuals who suffer from the disorder show a higher level in delays and disability. Seizures are also common due to structural abnormalities of the brain. Those affected may also suffer with apnea, the slowing or loss of breath for short periods of time.
Atelosteogenesis type I is a rare autosomal dominant condition. This condition is evident at birth and is associated with a very poor prognosis for the baby. It may be diagnosed antenatally.