Introduction: Hearing loss (HL), one of the commonest sensory disorders, can be caused by a variety of environmental and genetic factors 1. Genetic HL of nonsyndromic form can be caused by mutations in both nuclear and mitochondrial genes 3. Mitochondrial mutation (m.1555A>G) in the MTRNR1 gene is related to HL. The aim of this study is to describe the m.1555A>G genetic mutation in the MTRNR1 gene and its relationship with hearing loss plus medical literature review. Methods: A retrospective study of medical records of a patient who was diagnosed with profound hearing loss and m.1555A>G mutation. The medical literature review was performed using the MeshTerms: genetic hearing loss; non-syndromic hearing loss and m.1555A>G.