[Analyzing the relationship between genotype and phenotype of common deafness genic in two hereditary hearing loss...

To investigate the relationship between genotype and phenotype of common deafness genes by analyzing genotype and degree of hearing loss in deaf patients from deafness pedigrees.

Two small deafness pedigrees were selected. Nine locus mutations of four deafness genes were detected, and pure tone audiometry on family members were conducted simultaneously.

In LGR-1 pedigree, I :1, I :2, I :4, and II :5 carried single heterozygous mutation, which manifested by mild-moderate deafness in phenotype; while II :3 and II :4 genotype were double heterozygous mutation, and II :2 and III :1 genotype were composite mutation, both manifested by severe or profound deafness in phenotype. In HXL-2 pedigree, I :1 and I :2 carried single heterozygous mutation, which manifested by mild-moderate deafness while II :2, II :3, II :5 and III :2 presented with severe or profound deafness in phenotype, and II-1 genotype was double heterozygous, which manifested by profound deafness.

Patients who suffer from single heterozygous mutation mostly manifest with mild-moderate deafness in phenotype, and severe or profound deafness may be caused by other undetected mutations. Those who suffer from double or composite heterozygous mutations manifest with severe or profound deafness. Thus, there exists certain positive correlation between genotype and phenotype.