ANTLEY BIXLER SYNDROME PDF
A number sign (#) is used with this entry because of evidence that Antley-Bixler syndrome with disordered steroidogenesis (ABS1) is caused by homozygous or. Antley–Bixler syndrome, also called trapezoidocephaly-synostosis syndrome, is a rare, very severe autosomal recessive congenital disorder characterized by. This page from Great Ormond Street Hospital (GOSH) explains the causes, symptoms and treatment of Antley-Bixler syndrome and where to get help.
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Antley-Bixler Syndrome is a rare genetic disorder that is primarily characterized by distinctive malformations of the head and facial craniofacial area and additional skeletal abnormalities. For example, the disorder is typically associated with premature closure of the fibrous joints cranial sutures between particular bones of the skull craniosynostosis.
Many affected infants and children also may have a prominent forehead, underdeveloped midfacial regions midfacial hypoplasiaprotruding eyes proptosisand other craniofacial abnormalities.
Additional skeletal malformations are usually present, such as fusion of certain adjacent bones of the arms e. In addition, certain joints may become permanently flexed or extended in fixed postures joint contracturesresulting in restricted movements.
Rare Disease Database
Antley-Bixler Syndrome often appears to be inherited as an autosomal recessive trait. However, according syndromd researchers, other cases may result from spontaneous sporadic genetic changes mutations that may be transmitted as an autosomal dominant trait.
Antley-Bixler Syndrome is typically characterized by distinctive malformations of the head and facial craniofacial area. In most affected infants, there is premature closure of the fibrous joints sutures between bones of the front, upper sides, and back portion of the skull i. As a result, the head may appear abnormally short and broad brachycephalic and when viewed from above appears like a antkey. Additional craniofacial abnormalities may include a large, prominent forehead frontal bossing, underdeveloped middle regions of the face midfacial hypoplasia ; a bixlet nose with a low nasal bridge; protruding eyes proptosis ; and low-set, malformed dysplastic ears.
Antley-Bixler Syndrome is also characterized by additional, distinctive skeletal abnormalities. These may include fusion of adjacent bones of the arms, particularly the forearm bone on the thumb side of the arm radius and the long bone of the upper arm radiohumeral synostosis.
In some syndroem infants, antleu bony or thin layer of tissue may block the passageway between the nose and throat choanal stenosis or atresialeading to difficulties breathing. In such cases, without prompt, biixler treatment, potentially life-threatening complications may result. There are many affected individuals, however, who live relatively long longs. Some individuals with Antley-Bixler Syndrome may have additional physical abnormalities.
The specific underlying cause of Antley-Bixler Syndrome remains unclear. In many cases, the disorder appears to be inherited as an autosomal recessive trait. However, in other affected individuals, Antley-Bixler Syndrome is thought to be caused by spontaneous sporadic mutations of a gene known as FGFR2 that may be transmitted as an autosomal dominant trait in subsequent generations. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother.
In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease but usually will not show symptoms.
The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is 25 percent. Fifty percent of their children risk being carriers of the disease but generally will not show symptoms of the disorder. Twenty-five percent of their children may receive both normal genes, one from each parent, and will be genetically normal for that particular trait.
The risk is the same for each pregnancy. Parents of several individuals with Antley-Bixler Syndrome have been closely related by blood consanguineous. In recessive disorders, if both parents carry the same gene for the same disease trait, there is an increased risk that their children may inherit the two genes necessary for development of the disease.
The risk of transmitting the disorder from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child. As mentioned above, sporadic dominant mutations of the FGFR2 gene have been identified in some individuals with Antley-Bixler Syndrome. This gene regulates encodes the production of a protein known as a fibroblast growth factor receptor FGFR. According to researchers, genetic mutations that disrupt the functioning of such proteins may result in certain abnormalities during embryonic development, such as malformations of the craniofacial area and the limbs.
The gene that encodes the fibroblast growth factor receptor-2 protein has been mapped to the long arm q of chromosome 10 10q Chromosomes are found in the nucleus of all body somatic cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Chromosomes are further subdivided into bands that are numbered.
In a few individuals with symptoms characteristic of Antley-Bixler Syndrome, associated abnormalities have appeared to result from maternal use of the antifungal medication fluconazole during early pregnancy. The implications of these findings are unknown. According to cases reported in the medical literature, Antley-Bixler Syndrome has appeared to affect females more often than males.
Since the disorder was originally described inmore than 20 cases have been discussed in the literature. Symptoms of the following disorders can be similar to those of Antley-Bixler Syndrome. Comparisons may be useful for a differential diagnosis:.
Primary Craniosynostosis is a rare disorder of the skull that may be inherited as an autosomal dominant or autosomal recessive genetic trait. Premature closure of the bones sutures in the skull result in an abnormally shaped head. The severity of the symptoms and shape of the skull depend on which skull bones are prematurely closed.
This disorder is present at birth. In Kleeblattschadel Deformity, a type of Craniosynostosis, there is premature closure of multiple or all bones of the skull.
This condition causes the head to from a cloverleaf shape. The head may be larger than normal due to accumulation of fluid hydrocephaly in the skull. Plagiocephaly, another form of craniosynostosis, is characterized by the premature closure of the bones on one side of the skull.
The forehead may bulge and the orbit of the eye may be flat on one side.
Camptomelic Syndrome is a rare congenital skeletal disorder that is inherited as an autosomal recessive genetic trait.
It is characterized by short stature with bowing and an angular shape of the long bones of the legs. The bones of the shoulder and the pelvis are often abnormal.
Eleven pairs of ribs instead of the usual twelve may also be present. A flat face with widely spaced eyes and a small jaw may also be found in children with this disorder. Respiratory distress due to the underdevelopment of the rib cage, is the most serious complication of this condition.
Acrocephalosyndactyly Syndromes are rare disorders of infancy congenital that are characterized by a pointed head caused by the premature closure of the cranial sutures of the skull.
Antley–Bixler syndrome – Wikipedia
Other physical characteristics may include webbed fingers and a variety of skeletal deformities. Some characteristics of these syndromes are similar to those in Antley-Bixler Syndrome. Apert Syndrome is a rare inherited disorder characterized by mental retardation along with zntley of the head, fingers, and toes.
Apert Syndrome is also known as Acrocephalosyndactyly Type I. The head has a long narrow appearance with a pointed top acrocephaly or oxycephaly and some fingers may be webbed syndactyly. Crouzon Disease is a rare inherited disorder characterized by the premature closure of the bones of the skull craniosynostosis accompanied by unusual facial features, mental retardation, and disturbances in vision and hearing.
This disorder is also known as Acrocephalosyndactyly Type II. Spinal anomalies bkxler also be present. Saethre-Chotzen Syndrome is a rare congenital disorder thought to be inherited as an autosomal dominant genetic trait. This disorder is characterized by various craniofacial and skeletal abnormalities. Pfeiffer Syndrome is a rare disorder inherited as an autosomal dominant genetic trait that primarily affects the bones.
This disorder is also known as Acrocephalosyndactyly Type V.
Infants with Pfeiffer Syndrome usually have a short, pointed head acrobrachycephaly and other deformities of the face, jaws, and teeth. Webbed fingers or toes syndactyly and other abnormalities of the thumbs or big toes syndroome also occur. Symptoms can vary from mild to severe. Carpenter Syndrome is a rare inherited disorder characterized by abnormalities of bixxler head, hands, and genitals.
Mental retardation is also present in children with this disorder. This disorder is also known as Acrocephalopolysyndactyly Type II. Carpenter Syndrome is a form of craniosynostosis, marked by the premature closure of the bones of the skull resulting in an abnormally shaped head.
Other features may include down- slanting eyes, a flattened nose, low-set eyes, and an usually small jaw. Obesity and heart anomalies may also occur. Sakati Syndrome or Acrocephalopolysyndactyly Type III is a rare inherited disorder characterized by an abnormally shaped head and abnormalities of the fingers. Goodman Syndrome is a rare inherited disorder of infancy characterized by abnormalities of the head, hands, and genitals.
The head is typically abnormally shaped and the eyes may be low-set.
Mental retardation does not occur and hand deformities are less pronounced than in Carpenter Syndrome. In some cases, a diagnosis of Antley-Bixler Blxler may be suggested before birth prenatally based upon specialized tests such as ultrasound. During fetal ultrasonography, reflected sound waves are used to generate an image of the developing fetus. Ultrasound studies may reveal characteristic findings that may be associated with the disorder. The diagnosis of Antley-Bixler Syndrome is usually made after birth postnatally based upon a thorough clinical evaluation and characteristic physical findings.
Specialized testing, such as syndrrome advanced imaging techniques, may also be conducted to detect certain findings that may be associated with the disorder. The treatment of Antley-Bixler Syndrome is directed toward the specific symptoms that are apparent in each individual.
Such treatment may require the coordinated efforts of a team of medical professionals who may need to systematically and comprehensively plan an affected child’s treatment. In individuals with Antley-Bixler Syndrome, treatment may include surgical repair of malformations.
For example, in those with choanal atresia or stenosis, surgery or other appropriate methods may be required to decrease the airway obstruction or correct the malformation.
Surgery may also be recommended to correct certain craniofacial, skeletal, cardiac, urogenital, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors.
Early intervention may be important in ensuring that affected children reach their potential. For example, physical therapy is typically recommended to help improve the range of movement at certain joint contractures. Genetic counseling will also be of benefit for individuals with Antley-Bixler Syndrome and their families.