GENETIC EPIDEMIOLOGIC STUDIES OF EARLY-ONSET DEAFNESS IN THE UNITED-STATES SCHOOL-AGE POPULATION

Profound, early-onset deafness is present in 4-11 per 10,000 children, and is attributable to genetic causes in at least 50% of cases. Famil y history questionnaires were sent to 26,152 families of children with profound, early-onset deafness not known to be related to an environm ental cause. The probands were ascertained through the 1988-89 Gallaud et University Annual Survey of Hearing Impaired Children and Youth. Th e analysis is based on the responses that were received from 8,756 fam ilies. Classical segregation analysis was used to analyze the family d ata, and to estimate the proportions of sporadic, recessive and domina nt causes of deafness in the families. These data were consistent with 37.2% of the cases due to sporadic causes, and 62.8% due to genetic c auses (47.1% recessive, and 15.7% dominant). An earlier study using th e 1969-70 Annual Survey found 49.3% sporadic cases and 50.6% genetic, demonstrating that the proportion of sporadic cases of early-onset dea fness has significantly decreased since 1970.