Congenital contractural arachnodactyly (CCA), also known as Beals-Hecht syndrome, is a rare

autosomal dominant In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...

disorder. As with

Marfan syndrome Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with long arms, legs, fingers, and toes. They also typically have exceptionally flexible joints a ...

, people with CCA typically have an arm span that is greater than their height and very long fingers and toes. However, Beals and Hecht discovered in 1972 that, unlike Marfan's, CCA is caused by mutations to the

fibrillin-2 Fibrillin is a glycoprotein, which is essential for the formation of elastic fibers found in connective tissue. Fibrillin is secreted into the extracellular matrix by fibroblasts and becomes incorporated into the insoluble microfibrils, whi ...

(''FBN2'') gene rather than the

fibrillin-1 Fibrillin-1 is a protein that in humans is encoded by the ''FBN1'' gene, located on chromosome 15. It is a large, extracellular matrix glycoprotein that serves as a structural component of 10-12 nm calcium-binding microfibrils. These microfibr ...

(''FBN1'') gene.

Signs and symptoms

CCA is characterized by

contracture In pathology, a contracture is a permanent shortening of a muscle or joint. It is usually in response to prolonged hypertonic spasticity in a concentrated muscle area, such as is seen in the tightest muscles of people with conditions like spasti ...

s of varying degrees, mainly involving the large joints, which are present in all affected children at birth. The contractures may be mild and tend to improve over time, but permanently bent fingers and toes (

camptodactyly Camptodactyly is a medical condition that causes one or more fingers or toes to be permanently bent. It involves fixed flexion deformity of the proximal interphalangeal joints. Camptodactyly can be caused by a genetic disorder. In that case, it i ...

) are almost always present. In addition to long fingers and toes and a tall, slender body, people with CCA often have ears that appear to be crumpled, joint stiffness and underdeveloped muscles (muscular

hypoplasia Hypoplasia (from Ancient Greek ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.kyphoscoliosis Kyphoscoliosis describes an abnormal curvature of the spine in both a coronal and sagittal plane. It is a combination of kyphosis and scoliosis. This musculoskeletal disorder often leads to other issues in patients, such as under-ventilation of ...

). If kyphoscoliosis is present, it often becomes progressively worse and may require surgery. In some cases, the blood vessel that distributes blood from the heart to the rest of the body ( aorta) may be abnormally enlarged ( aortic root dilatation).

Causes

Congenital contractural arachnodactyly may be the result of new mutations in the ''FBN2'' gene or it may be inherited from a parent in an

pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Autosomal dominant - en

Diagnosis

CCA may be diagnosed through the physical characteristics associated with the disease of long, slender body and contractures of multiple joints, as well as other symptoms, such as muscular hypoplasia. Molecular

genetic tests Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

may be run using sequence analysis or

deletion Deletion or delete may refer to: Computing * File deletion, a way of removing a file from a computer's file system * Code cleanup, a way of removing unnecessary variables, data structures, cookies, and temporary files in a programming language * ...

duplication Duplication, duplicate, and duplicator may refer to: Biology and genetics * Gene duplication, a process which can result in free mutation * Chromosomal duplication, which can cause Bloom and Rett syndrome * Polyploidy, a phenomenon also known ...

analysis to look for mutations in the ''FBN2'' gene. Prenatal testing may be used for pregnancies with a risk of CCA, such as a parent or sibling with the disease.

Management

Joint contractures are treated using physical therapy to increase mobility and to improve the effects of underdeveloped muscles. Braces and/or surgery may be required to correct kyphoscoliosis. Children born with CCA are usually tested using echocardiograms every two years until the risks of an enlarged aorta (aortic root dilation) have been ruled out. If this is detected, it is managed with standard care for this condition.

Prognosis

Life expectancy may be affected by the disease symptoms present but it is not usually shortened for those with this disease.

References

External links

{{DEFAULTSORT:Beals Syndrome Cytoskeletal defects Systemic connective tissue disorders