Waardenburg syndrome was first described by the Dutch ophthalmologist P. J. Waardenburg in 1951. The symptoms of the condition may develop at any age, but they can vary widely among affected individuals, and not all individuals with Waardenburg syndrome experience hearing loss, which is the most frequent symptom.
Waardenburg syndrome type 1 is characterised by several symptoms:
Common symptoms in Waardenburg syndrome type 2 include congenital hearing loss, which is more common than in type 1 and affects around 50 per cent of those affected, and pigmentation disorders of the hair, skin and eyes.
However, unlike type 1, the distance between the eyes does not increase in type 2.
Type 3, also referred to as Klein-Waardenburg Syndrome, shares similarities with the first two types in terms of hearing loss and pigmentation disorders.
However, individuals with this type have a wider nose and greater distance between their eyes.
The unique characteristic of type 3 is the presence of upper limb issues, which can be exhibited through arm or shoulder weakness or abnormalities in the extremities.
Type 4 Waardenburg syndrome is characterised by pigmentation disorders similar to other types and can also lead to hearing loss.
Additionally, individuals with this type of Waardenburg syndrome are often affected by Hirschsprung's disease, a condition that can cause severe constipation and intestinal obstruction.
The genetic cause of Waardenburg syndrome is diverse. Mutations in six different genes have been identified in individuals affected by the condition, which are PAX3 (2q36.1), MITF (3p14-p13), SNAI2 (8q11.21), SOX10 (22q13.1), EDNRB (13q22.3), and EDN3 (20q13.32).
Mutations in some genes cause types 1 and 3 of Waardenburg syndrome to follow an autosomal dominant mode of inheritance. This means one parent with the mutation is enough for it to be inherited. Types 2 and 4 also follow a dominant mode of inheritance but can be inherited recessively. In this case, the altered genes may remain hidden for several generations before appearing.
Waardenburg syndrome has an estimated worldwide incidence of 1 in 20,000-40,000 people, with types 1 and 2 being more common and types 3 and 4 being less common. The syndrome is responsible for about 3% of all cases of congenital hearing loss.
Currently, there is no known cure for Waardenburg syndrome.
However, the syndrome does not affect life expectancy, and people affected by it can lead a normal life. It is important to manage the symptoms as they arise. The typical treatments for the syndrome are: