The prevalence of all types of<unk>  is estimated at around 1 in 42,000. Types 1 and 2 are by far the most common, with type 1 appearing to be slightly more common. In a 2015 review looking at 417 patients, type 1 was found to be the most common type, encompassing around half of all cases (47%), while type 2 was the second-most common type, encompassing around a third (33%). The vast majority (around 85%) of type 2 cases are type 2A. The prevalence of type 2B is unknown, as it was only reported in one 1996 study. Type 2C has so far only been found in one Italian family, and type 2D had only been found in 2 unrelated patients . The number of known cases of type 2E that involved neurological abnormalities was reported to be 23 , while the number of the rest is unknown. Type 3 is rarer than types 1, 2 and 4, comprising less than 2% of cases. Type 4 appears to encompass around a fifth of cases (19%). Of its subtypes, type 4C is by far the most common (about 71% of type 4), followed by type 4A (19%) and type 4B (10%). It is estimated that<unk>  is present in 2–5% of congenitally deaf people. Congenital deafness comprises around half of deafness as a whole. About 1 in 30 students in schools for the deaf have<unk> . The variable presentation of the syndrome makes it difficult to arrive at precise figures for its prevalence.
Waardenburg syndrome
Van Den Bosch syndrome
Alder–Reilly anomaly
Wildervanck syndrome
Aagenaes syndrome
Pelger–Huët anomaly
Singleton Merten syndrome
Koolen–De Vries syndrome