What is (are) Waardenburg syndrome ?
Waardenburg syndrome is a group of genetic conditions that can cause hearing loss and changes in coloring (pigmentation) of the hair, skin, and eyes. Although most people with Waardenburg syndrome have normal hearing, moderate to profound hearing loss can occur in one or both ears. The hearing loss is present from birth (congenital). People with this condition often have very pale blue eyes or different colored eyes, such as one blue eye and one brown eye. Sometimes one eye has segments of two different colors. Distinctive hair coloring (such as a patch of white hair or hair that prematurely turns gray) is another common sign of the condition. The features of Waardenburg syndrome vary among affected individuals, even among people in the same family.  The four known types of Waardenburg syndrome are distinguished by their physical characteristics and sometimes by their genetic cause. Types I and II have very similar features, although people with type I almost always have eyes that appear widely spaced and people with type II do not. In addition, hearing loss occurs more often in people with type II than in those with type I. Type III (sometimes called Klein-Waardenburg syndrome) includes abnormalities of the upper limbs in addition to hearing loss and changes in pigmentation. Type IV (also known as Waardenburg-Shah syndrome) has signs and symptoms of both Waardenburg syndrome and Hirschsprung disease, an intestinal disorder that causes severe constipation or blockage of the intestine.