How common is poland anomaly?
According to Genetics Home Reference, Poland syndrome has been estimated to occur in 1 in 20,000 newborns. This disorder occurs more than twice as often in males than in females. Poland Syndrome affects the right side of the body in about 75 percent of the time. Mild cases of Poland syndrome without hand involvement may not be visible until puberty, when the differences between the two sides of the chest become more apparent. Some cases of Poland syndrome may not be diagnosed because mild cases without hand involvement may never come to medical attention.