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Selected article Neurodegeneration with brain iron accumulation. Intend to add more general information and the symptoms (hopefully).

Sources following

Background
Initially called Hallervorden-Spatz syndrome. Describes a group of disorders characterized by an accumulation of brain iron and the presence of axonal spheroids in the central nervous system. Onset can occur at different ages, from early childhood to late adulthood. Iron accumulation can occur any where in the brain, with accumulation typically occurring in globus pallidus, substantia nigra pars reticula, striatum and cerebellar dentate nuclei. Symptoms can include various movement disorders, seizures, visual disturbances, and cognitive decline, usually in combination. The known causes of NBIA disorders are mutation in genes directly involved in iron metabolism, impaired phospholipid and ceramide metabolism, lysosomal disorders, as well as mutations in genes with unknown functions. The most common cause of NBIA is mutations in the PANK2 gene that cause pantothenate kinase associated neurodegeneration (PKAN) caused by an error in the metabolism of coenzyme A. There appears to be no particular type mutation that causes defective protein; mutations have been found on all 7 exons. Magnetic resonance imaging (MRI) is used to distinguish between the different forms of NBIA due to the accumulation of iron in different areas of the brain. Patients typically fall into two different categories: (1) early onset, rapid progression or (2) late onset, slow progression. The first type is considered to be the classic presentation, while they second type is the atypical presentation. Phenotypes of the different disorders appear to be dependent on age, i.e. amount of iron accumulation, cognitive ability. An effective treatment has yet to be found. In many cases electrical stimulation of the globus pallidus has been shown to produce improvement of dystonia severity

Classic presentation
Symptoms tend to present themselves at an age of 3 to 4 years old. Initially the symptoms are postural or gait difficulties that progress to pyramidal-extrapyramidal syndrome and dystonia. The extrapyramidal symptoms include behavior changes and dementia. The condition progresses resulting with the children in wheelchairs within a few years. Sleep analysis shows altered sleep architecture and overall less sleep, rapid eye movement (REM) sleep abnormalities absent. Iron accumulation in the brain results in a typical pattern, the pattern is referred to as "the eye of the tiger sign" defined by a pattern of central hyperintensity in an area of hypointensity.

Atypical presentation
Due to mutations in the PLA2G6 gene. Early onset patients have infantile neuroaxonal dystrophy (INAD); symptoms of which include mental and motor retardation which progressively gets worse, cerebellar ataxia, truncal hypotonia, pyramidal signs, and early visual disturbances due to optic atrophy. The "eye of the tiger sign" is not usually present when MR imaging is used, there is no central hyperintensity. However, iron deposit typically occur in the substantia nigra.