A rare developmental disorder (1 in 20,000 live births) which is present at birth (congenital).

It consists of underdevelopment of some or all of the chest, shoulder girdle and upper limb on one side of the body.

It affects males more frequently than females.

What are the symptoms?

The severity and extent of abnormalities varies between individuals, and it is rare to have all the features of Poland syndrome.

There is hypoplasia (underdevelopment) of the ribs and chest wall.

The most common abnormality of the shoulder girdle and chest wall is absence of part of the chest muscle (pectoralis major) which makes the anterior (front) fold of the armpit.

In girls, this may be associated with undergrowth or complete absence of a breast, and a small or absent nipple and areola (the areola is the pink or brown circle around the nipple). There may also be absence (agenesis) or hypoplasia of other chest muscles (including pectoralis minor).

The affected arm may be underdeveloped.

Abnormalities of the hand vary from a mild change in skin crease patterns to complete absence of some fingers.

In some cases the skin, and sometimes bone, has not separated during development and is still joined together (Syndactyly). Short fingers can also occur (Brachydactyly).