Mohr-Tranebjaerg Syndrome

At a glance

It is a novel rare genetic type of mitochondrial disease. It is characterized by deafness and dystonia. Progressive deafness becomes evident at age 3 to 5 years. Severe dysarthria and occasional bizarre posturing of head and neck are possible. Clinically, the features include the presence of dystonia, spasticity, dysphagia, and optic atrophy that appear in adult life. Patients are prone to seizures and lactate acidosis.

Synonyms

MTS; Dystonia-Deafness Syndrome; DDS; Deafness-Dystonia-Optic Atrophy Syndrome; DDP; Deafness Syndrome, Progressive, with Blindness, Dystonia, Fractures, and Mental Deficiency.

Incidence

There are few cases reported in the literature. The exact incidence remains unknown.

Genetic inheritance

It is believed inherited as an X-linked recessive inheritance. It is caused by a mutation on the TIMM8A (DDP) gene. A mutation in the same gene has been found as the cause of the Jensen Syndrome.

Pathophysiology

Pathologic changes are represented mainly by neuronal loss and glioses in the basal ganglia. This illness is a novel type of mitochondrial disease consisting of a defect in mitochondrial oxidative phosphorylation (OXPHOS), specifically caused by deficiencies in carrier proteins.

Clinical aspects

Progressive deafness occurs at age 3 to 5 years. It is a progressive syndrome, which includes myopia, decreased visual acuity, and abnormal electroretinogram, leading to cortical blindness, dystonia, fractures, and mental deficiency. The female carrier showed signs of minor neuropathy and mild hearing impairment.

Precautions before anesthesia

No specific precautions; however, in comparison to the other mitochondrial illnesses, blood sugar level and electrocardiogram should be considered.

Anesthetic considerations

Patients may develop lactic acidosis and seizure peroperatively.

Pharmacological implications

As reported with other mitochondrial diseases, use of neuromuscular blocking drugs is associated with significant implications, so careful monitoring is advisable.

Other conditions to be considered

• Jensen Syndrome (Opticoacoustic Nerve Atrophy with Dementia Syndrome): Characterized by profound sensorineural hearing loss with onset in infancy, followed in adolescence by progressive optic nerve atrophy with loss of vision and in adulthood by progressive dementia. It is inherited as an X-linked recessive pattern. Extensive intracerebral calcification affecting meninges, vessels, and neurons has been reported. Moderate diffuse wasting of skeletal muscles is reported and should be carefully assessed before anesthesia.

• ☞Mitochondrial Disease: Progressive multiorgan disease. The mitochondrial myopathies are a rare group of conditions affecting the respiratory chain and oxidative phosphorylation. A total of five proteins complexes make up the mitochondrial electron transport chain (see☞Diseases Complex).

References