The hearing impairment worsens over time, and most affected individuals have profound hearing loss by age 10.Individuals with Mohr Tranebjærg syndrome have normal vision during childhood, but they may develop vision problems due to breakdown of the nerves that carry information from the eyes to the brain (optic atrophy). Affected individuals can develop an increased sensitivity to light (photophobia) or other vision problems beginning in adolescence. Their sharpness of vision (visual acuity) slowly worsens, often leading to legal blindness in mid-adulthood. Genetics
This condition is caused by mutations in the TIMM8A gene. This gene is located on the long arm of X chromosome (Xq22). The protein encoded by this gene localizes to the intermembrane space in mitochondria where it functions in the import of nuclear encoded proteins into the mitochondrial inner membrane. How this produces the clinical picture is not yet clear. The pattern of inheritance is X-linked recessive. Where the female is a carrier, male offspring have a 50 percent chance of inheriting the disease and female offspring have a 50 percent chance of being a carrier. Where the male is affected, male offspring do not inherit the pathogenic mutation and females are obligate carriers.TIMM8A is also referred to as DDP. Koehler determined the function of the DDP gene and concluded that the Mohr-Tranebjaerg syndrome is a novel type of mitochondrial disease that is most likely caused by a defective mitochondrial protein-import system. Diagnosis
A combination of hearing impairment and recurrent infections due to XLA in a male patient should elicit sequencing of the TIMM8A gene.
Neuroimaging is employed to verify the presence of cerebral atrophy. In cases of suspected CGS; testing for XLA is possible. Differential diagnosis
This is long and includes

Arts syndrome
Autosomal recessive nonsyndromic sensorineural deafness type DFNB
Friedreich ataxia
MELAS syndrome
Mitochondrial DNA depletion syndrome (encephalomyopathic form with methylmalonic aciduria)
McLeod neuroacanthocytosis syndrome
Pendred syndrome
Usher syndrome type 1 and 2
Wolfram syndrome
X-linked spinocerebellar ataxia type 3 and 4

Treatment
Symptomatic Treatment
The treatment for Mohr-Tranebjærg vary depending on the symptoms and the evolution of these symptoms over time. Since hearing loss is prevalent in those with Mohr-Tranebjærg, hearing aids, devices, or cochlear implants are considered for increasingly serious cases. Immunoglobin
In those patients with secondary complications from the syndrome, intravenous immunoglobin may act to prevent infections in X-linked agammaglobulinemia, an inherited immune system disorder that can reduce the ability to fight infections. Similarly, those with XLA should avoid live viral vaccines. Patients that reach adulthood should seek regular evaluations from a neurologist to test the advancement of possible dementia and psychiatric manifestations

Genetic Counseling
Since the pattern of inheritance for Mohr-Tranebjærg is known to be X-linked recessive, genetic counseling is considered beneficial to families with known carriers. In the case that a female is a carrier, the statistical risk of male offspring inheriting the disease is 50%, while the probability that a female offspring will be a carrier is 50%. However, when a male is the carrier, the probability of having a female carrier offspring is 100%, and male offspring will not have any chance of inheriting the syndrome.