Question: What causes Poland syndrome ?
Answer: What causes Poland syndrome? The cause of Poland syndrome is unknown. Most evidence supports the idea that something abnormal happens during the sixth week of fetal development. This event most likely involves the vascular (blood and lymph) system. Speculations include: An interruption of the embryonic blood supply of the arteries that lie under the collarbone (subclavian arteries). This could be caused by the forward growth of the ribs reducing the flow of blood. A malformation of the subclavian arteries causes a reduced amount of blood delivered to the developing tissues on one side of the body.
Source: GARD

Question: Is Poland syndrome inherited ?
Answer: Is Poland syndrome inherited? Poland syndrome is rarely inherited and generally sporadic. Sporadic refers to the chance occurrence of a non-genetic disorder or abnormality that is not likely to recur in a family. In the few reported familial cases, researchers suggest that the condition may have stemmed from an inherited susceptibility to events such as interruption of blood flow that may predispose a person to the anomaly (i.e., make a person more likely to develop the anomaly).
Source: GARD