Neuropathy Ataxia and Retinitis Pigmentosa
NARP

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Prevalence of clinical parameters (%)







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Pubmed id number as a reference Organ system affected
Number of patients in the reference Percent affected patients (Between 0 and 1, eg. 0.1 = 10%)
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List of symptoms



Symptom/sign Organ system Percent affected Pubmed id Added on(yyyy-mm-dd) Edit/add reference
Retinitis pigmentosa nervous 100 % 2137962 2011-10-18
Basal ganglia pathology nervous 100 % 20953793 2012-07-25
Neuropathy nervous 100 % 20953793 2012-07-25
Cerebellar atrophy nervous 80 % 20953793 2012-07-25
Cerebral atrophy nervous 80 % 20953793 2012-07-25
Retinitis pigmentosa nervous 80 % 20953793 2012-07-25
Muscle weakness skeletal 80 % 20953793 2012-07-25
Ataxia nervous 75 % 2137962 2011-10-05
Neuropathy nervous 75 % 2137962 2011-10-05
Areflexia nervous 60 % 20953793 2012-07-25
Dysmetria nervous 60 % 20953793 2012-07-25
Babinski's sign nervous 50 % 2137962 2011-11-16
Dysarthria nervous 40 % 20953793 2012-07-25
Optic atrophy nervous 25 % 2137962 2011-10-05
Short stature skeletal 25 % 2137962 2011-10-05
Mental retardation nervous 25 % 2137962 2011-10-05
Nystagmus nervous 20 % 20953793 2012-07-25
Tremor nervous 20 % 20953793 2012-07-25



List of references:


A new mitochondrial disease associated with mitochondrial DNA heteroplasmy.
I J Holt, A E Harding, R K Petty, J A Morgan-Hughes,

A variable combination of developmental delay, retinitis pigmentosa, dementia, seizures, ataxia, proximal neurogenic muscle weakness, and sensory neuropathy occurred in four members of a family and was maternally transmitted. There was no histochemical evidence of mitochondrial myopathy. Blood and muscle from the patients contained two populations of mitochondrial DNA, one of which had a previously unreported restriction site for AvaI. Sequence analysis showed that this was due to a point mutation at nucleotide 8993, resulting in an amino acid change from a highly conserved leucine to arginine in subunit 6 of mitochondrial H(+)-ATPase. There was some correlation between clinical severity and the amount of mutant mitochondrial DNA in the patients; this was present in only small quantities in the blood of healthy elderly relatives in the same maternal line.

American journal of human genetics - Mar 1990



Heterogeneous patterns of tissue injury in NARP syndrome.
Jeffrey M Gelfand, Jacque L Duncan, Caroline A Racine, Leslie A Gillum, Cynthia T Chin, Yuhua Zhang, Qing Zhang, Lee-Jun C Wong, Austin Roorda, Ari J Green,

Point mutations at m.8993T>C and m.8993T>G of the mtDNA ATPase 6 gene cause the neurogenic weakness, ataxia and retinitis pigmentosa (NARP) syndrome, a mitochondrial disorder characterized by retinal, central and peripheral neurodegeneration. We performed detailed neurological, neuropsychological and ophthalmological phenotyping of a mother and four daughters with NARP syndrome from the mtDNA m.8993T>C ATPase 6 mutation, including 3-T brain MRI, spectral domain optical coherence tomography (SD-OCT), adaptive optics scanning laser ophthalmoscopy (AOSLO), electromyography and nerve conduction studies (EMG-NCS) and formal neuropsychological testing. The degree of mutant heteroplasmy for the m.8993T>C mutation was evaluated by real-time allele refractory mutation system quantitative PCR of mtDNA from hair bulbs (ectoderm) and blood leukocytes (mesoderm). There were marked phenotypic differences between family members, even between individuals with the greatest degrees of ectodermal and mesodermal heteroplasmy. 3-T MRI revealed cerebellar atrophy and cystic and cavitary T2 hyperintensities in the basal ganglia. SD-OCT demonstrated similarly heterogeneous areas of neuronal and axonal loss in inner and outer retinal layers. AOSLO showed increased cone spacing due to photoreceptor loss. EMG-NCS revealed varying degrees of length-dependent sensorimotor axonal polyneuropathy. On formal neuropsychological testing, there were varying deficits in processing speed, visual-spatial functioning and verbal fluency and high rates of severe depression. Many of these cognitive deficits likely localize to cerebellar and/or basal ganglia dysfunction. High-resolution retinal and brain imaging in NARP syndrome revealed analogous patterns of tissue injury characterized by heterogeneous areas of neuronal loss.

Journal of neurology - Mar 2011