Mitochondrial membrane protein-associated neurodegeneration (MPAN) is a rare subtype of neurodegeneration with brain iron accumulation disease (NBIA).
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Epidemiology
MPAN usually presents before 10 years old. At least one case of late-onset (35 years old) has been reported 3. Less than a hundred of cases have been reported so far and it accounts for approximately 5% of cases of NBIA 1.
Clinical presentation
Clinical features consist of early onset of gradually worsening varying neurological symptoms that overlap with those of PKAN. Neurological manifestations described include: parkinsonism, muscle atrophy, dysphagia, dysarthria, incontinence, ocular-motor disturbance, incontinence, cerebellar signs, psychiatric disorders, cognitive disorders, etc. 1
Pathology
MPAN is an autosomal-recessive genetic disorder caused by a mutation of the C19orf12 gene associated with inappropriate brain iron deposition.
Radiographic features
MRI
The most important findings are seen on T2-WI.
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T2:
- hyperintense linear signal in the medial medullary laminae (in-between the segments of the globus pallidus) 2
- hypointense signal in the globus pallidus (nonspecific finding suggestive of brain iron deposition) and, albeit less frequent, in the substantia nigra 2
- nonspecific periventricular hyperintensities 2
The eye of the tiger sign usually associated with PKAN has been described in at least two cases 2.
Cerebellar atrophy has also been described in some cases.