Mitochondrial-membrane Protein-Associated Neurodegeneration (MPAN) is an inherited autosomal recessive disorder caused by mutations in the C19orf12 gene. This gene is found on chromosome 19 and is believed to play a role in fatty acid metabolism.
MPAN has distinctive clinical symptoms that differentiate it from other forms of NBIA.
Onset occurs in childhood to early adulthood with spasticity that is more prominent than dystonia, weakness in muscles caused by motor axonal neuropathy, optic atrophy, and neuropsychiatric (mental disorder due to disease of the nervous system) changes.
Most affected individuals are still able to walk as they reach adulthood.
Psychiatric signs are common, including impulsive or compulsive behavior, depression and frequent mood changes.
Unlike most other forms of NBIA, the vast majority of individuals with MPAN develop progressive cognitive decline.
Clinical Diagnosis of MPAN
An eye exam and an MRI of the brain (T2 –weighted) that shows iron accumulation in the globus pallidus and substantia nigra are keys to diagnosing MPAN.
The most common symptoms are speech and gait difficulties, optic atrophy, generalized dystonia, spasticity and parkinsonism.
Commonly, all age groups experience a decline in cognitive ability that progresses to dementia; prominent neuropsychiatric abnormalities; and movement problems caused by nerve cell abnormalities.
Studies reveal a loss of nerve cells, widespread iron deposits, and abnormal axons (a part of nerve cells) called spheroid bodies, in the basal ganglia.
Lewy neurites, which are abnormal clusters of protein that develop inside the nerve cells, are present in the globus pallidus, and Lewy bodies and neurites are widespread in other areas of the midbrain and in regions of the globus pallidus called the corpus striatum.
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Consider treating with drugs that act on dopamine in the brain.
Neuropsychiatric symptoms may require treatment by a psychiatrist.
Medical providers also may seek to manage the disease by performing regular eye exams, as well as neurological tests for dystonia, spasticity and parkinsonism. That may include evaluation of the affected individual’s ability to walk and speak for possible physical, occupational and/or speech therapy.
Please see the link on this page for more detailed clinical information on MPAN at Gene Reviews, which was used as a source for some of the above information. Gene Reviews is primarily for the use of genetics professionals so the terminology and information may be difficult to understand for the general public.
Gene Review Authors: Allison Gregory, MS, CGC, Monika Hartig, MD, Holger Prokisch, PhD, Tomasz Kmiec, MD, Penelope Hogarth, MD, and Susan J Hayflick, MD.
Please visit the NBIA Disorders Association website, which was used as a primary source for the above information.