Waardenburg syndrome in childhood deafness in Cameroon

BACKGROUND: Waardenburg syndrome (WS) is a rare hereditary disorder essentially characterised by deafness and pigment disorders of the eyes, hair and skin. METHODS: Between October 2010 and December 2011, we identified six patients with WS during an aetiological survey of 582 deaf participants recruited in schools for the deaf and ear, nose and throat outpatient clinics in seven of the ten regions of Cameroon. Two classic characteristics of WS were used as diagnostic criteria: deafness and pigmentation abnormalities (heterochromia iridis, white forelock and depigmented skin patches). In addition, to identify dystopia canthorum, a sign of WS type I, we calculated the W-index. RESULTS: WS comprised 1% of the whole sample, 7% of the genetic cases, and 50% of the genetic syndromic cases. All patients with WS had severe to profound congenital sensorineural and symmetrical hearing loss with flat audiograms. They also had pigment disorders of the eyes and the skin. In the absence of dystopia canthorum, they were all classified as having WS type II. The pedigree was suggestive of autosomal dominant inheritance in two cases, and the four others seemed to be de novo cases. CONCLUSION: The results suggest that WS type II is the most common syndromic form of hearing loss among Cameroonians. This has implications for retrospective genetic counselling and hearing tests for earlier management in affected families.