Importance of congenital cytomegalovirus infections as a cause for pre-lingual hearing loss

BackgroundNo large population based studies of newborn hearing screening have reported the population frequency of more than one specific form of deafness.ObjectivesTo combine available data on the overall incidence of pre-lingual deafness with estimates for specific causes to gain insight into age-related changes in the prevalence of the major causes of pre-lingual deafness.Study designThe incidence of deafness in England was adjusted for the exclusion of unilateral losses to obtain an overall estimate of 1.86 per 1000 births in the United States. Longitudinal data were used to estimate that the prevalence rises to 2.70 per 1000 at age 4. The genetic component was estimated sentinel phenotype analysis, and studies of single entities were integrated to estimate the prevalence of specific causes.Results and conclusionsCongenital CMV infections and connexin mutations are the two major causes of deafness at birth, while causes for enlarged vestibular aqueduct along with congenital CMV infection are the major causes of pre-lingual hearing loss that is not expressed at birth. By molecular screening tests on newborn blood spots for four known causes, 60% of the infants who develop late onset pre-lingual hearing loss could be identified at birth.