Deafness means partial or complete hearing impairment and is one of the most 
prevalent sensory defects in humans. It can be due to genetic or environmental 
causes or a combination of both and may be Syndromic (associated with additional 
clinical features) or nonsyndromic (no other recognizable abnormal associated 
phenotype). The overall impact of hearing impairment is greatly influenced by 
the severity of hearing defect and by the age of onset. If defect is severe and 
presents in early childhood, it has dramatic effect on speech acquisition and 
thereby cognitive and psychosocial development. The mutations shown in the paper 
results in the conformational changes of protein and influence the phenotype of 
the affected individuals. For recessive cases of deafness it is possible to 
reduce the incidence of deafness by carrier screening in the families with 
multiple affected individuals and genetic counselling. Pendred Syndrome can be 
characterized by the triad composed of familial goitre, abnormal perchlorate 
discharge and congenital deafness.