Diseases

Yes. For reasons not understood, Poland syndrome is twice as likely to involve the right side of the body.

Geneticists currently hold that Poland syndrome is rarely inherited and generally is a sporadic event. There are rare instances where more than one individual has been identified with Poland syndrome either in the immediate or extended family. Experience with an affected parent passing the syndrome to offspring has been described. Similarly, there are reports in the literature of affected siblings born to unaffected parents. The exact mode of genetic transmission has not been determined. Research is centering on inherited mechanisms dealing with intrauterine reduction of blood flow to the affected areas.

The severity of Poland syndrome is variable, and it is possible for mild cases not to be evident until puberty when breast tissue and chest muscle mass development become more obvious. It is felt, therefore, that cases may be misdiagnosed and underreported. Experts currently are reporting an incidence of one in 10,000 to one in 100,000 live births. For reasons unknown, boys are more likely than girls to have Poland syndrome.

When the changes of Poland Syndrome are noted, the diagnosis can be suspected in the newborn period. Specialized studies (x-rays, computerized tomography [CT scans]) and magnetic resonance imaging (MRI) studies may be utilized to delineate the anatomy of the involved area(s). Such an understanding is necessary for reconstructive surgery (see below). Mild cases of Poland syndrome may not be apparent until the child has matured or even until puberty. During this time, differences in body development may be more pronounced—especially in female breast development.

Reconstructive surgery is the main treatment for those with Poland syndrome. Either existing chest muscle or transplanting muscle from another body area may be used to develop symmetry between the affected and unaffected side. If chest-wall ribs are underdeveloped or missing, bioengineered cartilage can be implanted to help give the chest a more normal appearance. Reconstructive surgery may be considered in males as young as 13 years of age. In females, in order to ensure breast similarity in size and character, reconstructive surgery is often postponed until breast development on the uninvolved side has been completed. Therapeutic tattooing can be uses to create the appearance of an areola and nipple.

While the complete expression of the physical changes associated with Poland syndrome vary among patients, common themes include:

1. underdevelopment or absence of the main chest muscle (pectoralis) as well as secondary muscles of the chest and armpit region;
2. the end of the pectoralis muscle attachment to the breastbone (sternum) is absent;
3. the nipple, areola, and (in females) underlying breast tissues are underdeveloped or absent;
4. short and webbed fingers (cutaneous syndactyly) on the affected side; and
5. armpit hair on the affected side is missing.

Other names for Poland syndrome include Poland sequence, Poland anomaly, Poland syndactyly, and absence of the pectoralis muscle with syndactyly.

The cause of Poland syndrome is not known. The disorder is currently considered "a nonspecific developmental field defect" occurring at about the sixth week of fetal development. Diminished blood flow through the subclavian artery that supplies blood to the arm has been blamed, but final proof for this idea is lacking. Speculation has involved two hypotheses. One proposes that the underlying ribs on the affected side grow too quickly in a forward growth plane and thus reduce the flow of blood in the arteries leading to the overlying pectoralis muscle and arm on the affected side. Another proposal is that a malformation of the embryonic blood vessel serving the pectoralis muscle and arm/hand on that side of the body limits blood flow to these structures. To date no animal research has provided conclusive support for these proposals.

First described by the 19th-century British anatomist Sir Alfred Poland, Poland syndrome is a unique pattern of one-sided malformations that are present at birth (congenital malformations). Poland syndrome is noted for the underdevelopment or absence of the chest (pectoralis) muscles on one side of the body as well as webbing of the fingers (cutaneous syndactyly) on the hand of the same side (ipsilateral side) of the body.

The child with Poland syndrome usually is entirely normal except for the problems already noted. The skin in the involved area may be abnormally thinned or missing underlying fat normally present beneath the skin. Very rarely, the rib cage on the involved side may be underdeveloped or missing. Equally rare may be the abnormal development of the shoulder blade (scapula) or bones of the forearm (radius and ulna) on the affected side of the body. Spine and kidney malformations are also occasionally reported in patients with Poland syndrome. Intelligence is not impaired in Poland syndrome.