Congenital contractural arachnodactyly represents a broad spectrum of characteristics. The features are quite variable, both within and between families. The classic form is characterized by a Marfan-like appearance (tall and slender with arm span exceeding height), arachnodactyly (long slender fingers and toes), 'crumpled' ears, contractures of major joints from birth (particularly knees, elbows, fingers, toes, and hips), bowed long bones, muscular hypoplasia (underdeveloped muscles), kyphosis/scoliosis, aortic root dilation, and various craniofacial abnormalities (such as micrognathia, high arched palate, scaphocephaly (premature fusion of the sagittal suture of the skull leading to a long, narrow head), brachycephaly (premature fusion of the coronal suture, leading to a short skull), and frontal bossing).
At the most severe end of the spectrum is a rare type with very few reported cases. In addition to the typical skeletal findings (arachnodactyly, joint contractures, scoliosis) and abnormally shaped ears, infants with the severe/lethal form have multiple cardiovascular and gastrointestinal abnormalities.
The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
|Signs and Symptoms||Approximate number of patients (when available)|
|Abnormality of the helix||90%|
|Abnormality of the palate||90%|
|Camptodactyly of finger||90%|
|Disproportionate tall stature||90%|
|External ear malformation||90%|
|Elbow flexion contracture||86%|
|Knee flexion contracture||81%|
|Abnormality of the mitral valve||7.5%|
|Aortic root dilatation||-|
|Atria septal defect||-|
|Autosomal dominant inheritance||-|
|Bicuspid aortic valve||-|
|Calf muscle hypoplasia||-|
|Mitral valve prolapse||-|
|Patent ductus arteriosus||-|
|Ulnar deviation of finger||-|
|Ventricular septal defect||-|
Congenital contractural arachnodactyly is caused by mutations in the FBN2 gene. The FBN2 gene provides instructions for producing the fibrillin-2 protein. Fibrillin-2 binds to other proteins and molecules to form threadlike filaments called microfibrils. Microfibrils become part of the fibers that provide strength and flexibility to connective tissue. Additionally, microfibrils hold molecules called growth factors and release them at the appropriate time to control the growth and repair of tissues and organs throughout the body. A mutation in the FBN2 gene can reduce the amount and/or quality of fibrillin-2 that is available to form microfibrils. As a result, decreased microfibril formation weakens the elastic fibers and allows growth factors to be released inappropriately, causing tall stature, deformities of the fingers and toes, and other characteristic features of congenital contractural arachnodactyly.
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.
Genetic Analysis of Limb Malformation Disorders
University of Washington SOM
Department of Pediatrics
Division of Genetics & Developmental Medicine
1959 NE Pacific St. HSB RR349 B
Seattle, WA 98195-6320 USA
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My nephew has been diagnosed with Beals syndrome (also known as congenital contractural arachnodactyly). Can you provide me with information? See answer
I have Beals syndrome (also known as congenital contractural arachnodactyly). I am a 19-year-old female and I was wondering how tall I would be because of this condition? The symptom is having a tall stature, but how tall? I'm 5'3 right now. See answer