Beals Syndrome Health Article

Definition

Beals syndrome, also known as Beals contractural arachnodactyly (BCA), congenital contractural arachnodactyly, or Beals-Hecht syndrome, is a rare genetic disorder that involves the connective tissue of the skeleton.

Description

Individuals diagnosed with Beals syndrome usually have long, thin, fingers and toes that cannot be straightened out because of contractures, meaning a limited range of motion in the joints of their fingers, hips, elbows, knees, and ankles. They also have unusual external ears that appear crumpled. Contractures of the elbows, knees, and hips at birth are very common. Some babies also have clubfoot, causing one or both feet to be turned in towards each other at the ankles. In most individuals, the contractures improve with time and the clubfoot responds well to physiotherapy.

The condition occurs when fibrillin, an important component of the body's connective tissue (the glue and scaffolding of the body; for example, bones, cartilages, tendons, and fibers) is not made properly by the body. The gene responsible for making fibrillin is called FBN2 and it is located on chromosome 5. Any mutation (change) occurring in the FBN2 gene results in Beals syndrome.

Genetic profile

Beals syndrome is caused by a mutation occurring in a gene. Genes are units of hereditary material passed from a parent to a child through the egg and sperm. The information contained in genes is responsible for the development of all the cells and tissues of the body. Most genes occur in pairs: one copy of each pair is inherited from the egg cell produced by the mother and the other copy of each pair comes from the sperm cell of the father. One of these genes (called FBN2) tells the body how to make fibrillin-2, a specific type of protein. Proteins are substances made in the body that consist of chemicals called amino acids. Fibrillin-2 is an important part of connective tissue. Connective tissue provides structural support and elasticity to the body. It is made up of various components, including elastic-like fibers, and fibrillin-2 is thought to play a role in ensuring that the elastic fibers of the connective tissue are assembled properly early in development; however, the precise function of fibrillin-2 remains unknown. People with Beals syndrome have a mutation in one copy of their FBN2 gene. As a result, the fibrillin-2 they make is unable to work properly and this causes the BCA symptoms.

Beals syndrome is inherited as a dominant condition. In dominant conditions, a person needs to have only one altered gene copy to develop the condition. The mutation in the FBN2 gene that causes Beals syndrome can be inherited from a parent who is also affected with BCA. Individuals with Beals syndrome have a 50% chance in each pregnancy to have a child with Beals syndrome.

Sometimes Beals syndrome cannot be traced back to a parent with the condition. In these cases, the genetic change is said to be a spontaneous mutation. This means that some unknown event has caused the FBN2 gene (which functions normally in the parent) to mutate in either the sperm of the father or the egg of the mother. If fertilization occurs, the resulting individual will have Beals syndrome. A person who has Beals syndrome due to a spontaneous mutation can then pass on this altered FBN2 gene to his or her future children.

Demographics

Beals syndrome affects males and females of all ethnic groups. It is a rare condition and accurate estimates of the number of affected people are not available.

Signs and symptoms

Besides the general appearance displayed by persons with Beals syndrome (tall and thin, contractures, with typical crumpled ear), symptoms of the disorder vary from one affected individual to the next. Sometimes, arms are disproportionately long for the height of the person. Other less common features may include a small chin, protruding forehead, and a high arch in the roof of the mouth (palate).

An abnormal bending or twisting of the spine (kyphosis/scoliosis) is seen in about half of individuals diagnosed with Beals syndrome and can occur in early infancy. This bending and twisting of the spine tends to worsen over time. Some individuals may also have an abnormal indentation or protrusion of their chest wall. Decreased muscle bulk, especially in the lower legs, is also a common sign of Beals syndrome.

Less common symptoms of Beals syndrome include heart and eye problems. The most frequent heart problem involves one of the heart valves (mitral valve prolapse) and may necessitate medication prior to dental or other surgeries so as to prevent infection. More serious heart problems may occur but are rare. The aorta, the major blood vessel carrying blood away from the heart, may rarely enlarge. This condition usually requires medication to prevent further enlargement or occasionally, surgery. A small number of individuals with Beals syndrome may also be nearsighted and require eye glasses.