The recessive mode of transmission accounts for approximately 75% of inherited non syndromic deafness cases. We have previously designed the conditions for linkage studies of this highly heterogeneous disorder [Guilford et al. (1994) Nature Genet. 6, 24-28]. Here, using a similar approach, we have studied the segregation of a gene responsible for congenital, profound and fully penetrant sensorineural deafness in a consanguineous family living in an isolated region of Lebanon. A maximum lod score of 8.03 (theta = 0.00) was detected with a new polymorphic marker, AFMa052yb5 (D2S2144). Observed recombinants and homozygosity mapping define a maximum interval of 2 cM for this gene, DFNB6, which lies between AFMb346ye5 (a new polymorphic marker) (D2S2303) and AFM254vc9 (D2S174) on chromosome 2p22-23.