Mohr-Tranebjærg syndrome

Mohr-Tranebjærg syndrome (MTS), also known as Deafness-dystonia-optic neuronopathy syndrome, is a rare X-linked recessive genetic disorder characterized by sensorineural hearing loss, dystonia, and optic atrophy. The syndrome was first described by Torben Mohr and Lisbeth Tranebjærg in the late 20th century.

Clinical Features

The primary symptoms of Mohr-Tranebjærg syndrome include progressive sensorineural deafness, dystonia, and optic atrophy. The hearing loss typically begins in early childhood and progresses to profound deafness by adolescence. Dystonia, a movement disorder characterized by involuntary muscle contractions, usually develops in late childhood or early adolescence. Optic atrophy, which leads to vision loss, typically begins in adolescence or early adulthood.

Other symptoms may include intellectual disability, behavioral problems, and neurological abnormalities such as seizures and ataxia.

Genetics

Mohr-Tranebjærg syndrome is caused by mutations in the TIMM8A gene, which is located on the X chromosome. This gene provides instructions for making a protein that is involved in the transport of proteins into the mitochondria, the energy-producing centers of cells. Mutations in the TIMM8A gene disrupt this process, leading to the symptoms of Mohr-Tranebjærg syndrome.

Because MTS is an X-linked recessive disorder, it affects males more severely than females. Females with a mutation in one of their two X chromosomes are typically carriers of the disorder, while males with a mutation in their only X chromosome are affected by the syndrome.

Diagnosis and Treatment

Diagnosis of Mohr-Tranebjærg syndrome is based on the presence of characteristic clinical features and can be confirmed by genetic testing.

There is currently no cure for MTS. Treatment is symptomatic and supportive, and may include hearing aids or cochlear implants for hearing loss, medications or physical therapy for dystonia, and low-vision aids for vision loss.

See Also

• Dystonia
• Optic atrophy
• Sensorineural hearing loss
• X-linked recessive inheritance

NIH genetic and rare disease info

• NIH info on Mohr-Tranebjærg syndrome

Mohr-Tranebjærg syndrome is a rare disease.

Mohr-Tranebjærg syndrome Resources
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