Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016719 (Friedreich's ataxia)
 2,098 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The brain-stem involvement in Friedreich's ataxia (FA) was studied by using brain-stem auditory evoked potentials (BAEPs) and the blink reflex. Ten out of 18 patients had abnormal BAEPs, the main abnormality being complete absence of responses and disappearance of wave V. Combined degeneration of the peripheral and central acoustic pathways probably accounts for these findings. The blink reflex was abnormal in 50% of the cases. The outstanding abnormality was bilateral delay of late responses with normal early response, which could be correlated with the known pallor of the descending trigeminal tracts. In contrast with BAEP findings, blink reflex abnormalities did not correlate with either the age of patients or the severity and duration of the disease. These data suggest a difference in susceptibility to degeneration between the auditory system and neuronal system subserving the blink reflex. We conclude that systematic BAEP and blink reflex recording is useful in the electrophysiological evaluation of FA patients.
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PMID:Brain-stem auditory evoked potentials and blink reflex in Friedreich's ataxia. 189 51

Friedreich's ataxia is the most common inherited ataxia. Ninety-six percent of patients are homozygous for GAA trinucleotide repeat expansions in the first intron of the frataxin gene. The remaining cases are compound heterozygotes for a GAA expansion and a frataxin point mutation. We report here the identification of 10 novel frataxin point mutations, and the detection of a previously described mutation (G130V) in two additional families. Most truncating mutations were in exon 1. All missense mutations were in the last three exons coding for the mature frataxin protein. The clinical features of 25 patients with identified frataxin point mutations were compared with those of 196 patients homozygous for the GAA expansion. A similar phenotype resulted from truncating mutations and from missense mutations in the carboxy-terminal half of mature frataxin, suggesting that they cause a comparable loss of function. In contrast, the only two missense mutations located in the amino-terminal half of mature frataxin (D122Y and G130V) cause an atypical and milder clinical presentation (early-onset spastic gait with slow disease progression, absence of dysarthria, retained or brisk tendon reflexes, and mild or no cerebellar ataxia), suggesting that they only partially affect frataxin function. The incidence of optic disk pallor was higher in compound heterozygotes than in expansion homozygotes, which might correlate with a very low residual level of normal frataxin produced from the expanded allele.
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PMID:Friedreich's ataxia: point mutations and clinical presentation of compound heterozygotes. 998 22

We report a 60-year-old man with a 6-year history of tremor in his hands. He noted the onset of short of breath and gait disturbance in 1994; both of these symptoms were slowly progressive. Then recently he developed fever two months prior to the present admission. He was admitted to the rheumatology department of our hospital and neurological consultation was asked on December 13, 2000. On neurologic examination, he showed Gottron sign and fine crackle in both lungs. Pertinent neurological findings were bilateral dysmetria in finger-to-nose and heel-to-knee tests and a broad-based gait. In addition, he showed intention tremor in upper extremities more on the left. Romberg sign was positive. Deep tendon reflexes were decreased. Vibratory sensation was reduced at the wrists. The patient's hemoglobin was 11.1 g/dl, with a mean corpuscular volume of 92.0 fl. Vitamin B12 level was 190 (reference range, >230 pg/ml). Serum lactic acid, pyruvic acid and ceruloplasmin were slightly elevated. Chest X-ray showed interstitial pneumonia. Muscle biopsy showed grouping of small angular fiber. Brain MRI showed diffuse atrophy of the cerebral cortex and the cerebellum hemisphere. Thalamotomy did not improve his tremor. He was admitted again in November 2001. General worsening of his neurological findings was observed. IL2-receptor was markedly elevated. Serum anti-Hu, Yo and Ri antibodies were negative. An anaplastic carcinoma was found in his jejunum. He died from respiratory failure in February 2002. He was discussed in a neurological CPC and the chief discussant arrived at a conclusion that the patient had paraneoplastic syndrome. Other diagnosis entertained included MERRF, GSS, Ramsay Hunt syndrome, subacute combined degeneration, spinocerebellar degeneration. Majority of the participants thought that paraneoplastic syndrome was most likely. Post-mortem examination revealed poorly differentiated carcinoma in the small intestine. Myeline pallor was noted in the posterior and the lateral columns in the thoracic spine. Neuronal cell loss was observed in the Purkinje cell and granular cell layer in the cerebellum. Sural nerve demonstrated loss of myelinated fibers and grouping of small fibers. Neuropathological findings were consistent with Friedreich ataxia; nevertheless, no mutation was reported in frataxin in Japan. The neuropathologist concluded that neuropathological diagnosis was a spinocerebellar ataxia with neuropathological similarities to Friedreich ataxia.
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PMID:[A 60-year-old man with intention tremor as an initial symptom followed by cerebellar ataxia, peripheral neuropathy and dementia]. 1614 16

Optic neuropathy is common in mitochondrial disorders, but poorly characterized in Friedreich's ataxia (FRDA), a recessive condition caused by lack of the mitochondrial protein frataxin. We investigated 26 molecularly confirmed FRDA patients by studying both anterior and posterior sections of the visual pathway using a new, integrated approach. This included visual field testing and optical coherence tomography (OCT), pattern visual evoked potentials (P-VEPs) and diffusion-weighted imaging. The latter was used to study optic radiation by calculating water apparent diffusion coefficients (ADC). All patients suffered optic nerve involvement with their disorder. Different patterns of visual field defects were observed and a variably reduced retinal nerve fiber layer thickness was seen by OCT in all cases. P-VEPs were abnormal in approximately half of the patients. Decreased visual acuity and temporal optic disc pallor were present in advanced stages of the disease, but only five patients were symptomatic. Two of these patients suffered a sudden loss of central vision, mimicking Leber's hereditary optic neuropathy (LHON), and of the other three symptomatic patients two were noted to be compound heterozygotes. ADC values of optic radiations in patients were significantly higher than controls (P < 0.01). Retinal nerve fiber layer thickness at OCT and P-VEPs correlated with age at onset and ICARS total score. ADC values correlated with age at onset, disease duration, GAA triplet expansion size, ICARS total score and P-VEPs. Visual pathway involvement is found consistently in FRDA, being previously underestimated, and we here document that it also involves the optic radiations. Occasional LHON-like cases may occur. However, optic neuropathy in FRDA substantially differs from classic mitochondrial optic neuropathies implying a different pathophysiology of visual system degeneration in this mitochondrial disease.
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PMID:Visual system involvement in patients with Friedreich's ataxia. 1893 86