Poland syndrome ... (Poland syndrome)
Poland's syndrome is a process in which affected individuals born with absent or underdeveloped muscles on one side of the body, resulting in disturbances that may affect the chest, shoulder, arm and hand. The extent and severity of abnormalities vary among affected individuals to others.
In people with Poland syndrome is usually absent the pectoralis major. In most affected individuals, the missing part is the large section of the muscle that normally extends from the upper arm to the breastbone. The pectoralis major muscle abnormality can cause the breast to appear concave. In some cases, they may be absent or underdeveloped additional muscles on the affected side of the torso, including the muscles of the chest, and shoulder side wall. There may also be abnormalities in the rib cage, as shorter and remarkable ribs due to lower subcutaneous fat. They can also develop abnormalities in the breast and nipple and axillary hair may be sparse or abnormal distribution. In most cases, abnormalities in the chest area do not cause health problems or affect the movement.
Many people with Poland syndrome have abnormalities of the hand on the affected side, usually including brachydactyly, syndactyly underdeveloped vestigial fingers. This combination of anomalies of the hand is called symbrachydactyly. Some affected individuals have only one or two of these features, or have a slight abnormality of hands is hardly noticeable. The radius and ulna are shortened in some people with Poland syndrome, but this reduction can also be difficult to detect. Mild cases of Poland syndrome without the participation of the hand may not be evident until puberty, when it becomes evident asymmetry between the two sides of the chest. On the contrary, severely affected individuals have abnormalities of the chest, hand, or both, that are evident at birth. In rare cases, most affected people have abnormalities of internal organs such as dextrocardia, in which a lung or a kidney or heart has an abnormal situation standing on the right side of the chest. Rarely, abnormalities in the chest and hand occur on both sides of the body; however, it is unclear whether this condition is a variant of Poland 's syndrome or a different entity.
The cause of Poland syndrome is unknown. It is believed to be due to an interruption of blood flow during development before birth, which occur approximately the sixth week of embryonic development and affects the blood vessels become the subclavian and vertebral arteries on either side of organism. Normally the arteries supplying blood to embryonic tissues that give rise to the chest wall and hand on their respective sides. Variations on the site and extent of the disruption can explain the variety of signs and symptoms that occur in Poland syndrome. The anomaly of the apical ectodermal ridge, which helps direct development of the extremities, may also be involved in this process. In rare cases, it is believed that Poland's syndrome is due to a genetic change that can be transmitted from parents to children, but have not been identified related genes.
Most cases of Poland syndrome are sporadic, meaning they are not inherited and occur in people with no history of the disease in their families. Rarely, this entity is transmitted from generation to generation in families. In these families the process appears to be inherited in an autosomal dominant pattern, which means that a copy of an altered gene in each cell is sufficient to express the process, although they have not identified associated genes.