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Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion.
Ann Neurol. 1997 May; 41(5):675-82.AN

Abstract

We studied genotype-phenotype correlations in a group of 100 patients with typical Friedreich ataxia (FRDA), and in three groups of patients with atypical clinical presentations, including 44 Acadian FRDA, 8 late-onset FRDA (LOFA), and 6 FRDA with retained reflexes (FARR). All patients, except 3 with typical FRDA, carried two copies of the FRDA-associated GAA triplet repeat expansion. Overall, the phenotypic spectrum of FRDA appeared to be wider than defined by the currently used diagnostic criteria. Our study indicated the existence of several sources of variability in FRDA. Patients with larger GAA expansions tended to have earlier onset and were more likely to show additional manifestations of the disease. Mitotic instability of the expanded GAA repeats may partially account for the limited degree of correlation between expansion sizes as determined in lymphocytes and clinical parameters. Some clinical variants associated with specific FRDA haplotypes, such as Acadian FRDA and FARR, turned out to be unrelated to expansion sizes. No polymorphism in the frataxin coding sequence could be associated with these clinical variants.

Authors+Show Affiliations

Centre de Recherche Louis-Charles Simard, Montreal, Quebec, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9153531

Citation

Montermini, L, et al. "Phenotypic Variability in Friedreich Ataxia: Role of the Associated GAA Triplet Repeat Expansion." Annals of Neurology, vol. 41, no. 5, 1997, pp. 675-82.
Montermini L, Richter A, Morgan K, et al. Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion. Ann Neurol. 1997;41(5):675-82.
Montermini, L., Richter, A., Morgan, K., Justice, C. M., Julien, D., Castellotti, B., Mercier, J., Poirier, J., Capozzoli, F., Bouchard, J. P., Lemieux, B., Mathieu, J., Vanasse, M., Seni, M. H., Graham, G., Andermann, F., Andermann, E., Melançon, S. B., Keats, B. J., ... Pandolfo, M. (1997). Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion. Annals of Neurology, 41(5), 675-82.
Montermini L, et al. Phenotypic Variability in Friedreich Ataxia: Role of the Associated GAA Triplet Repeat Expansion. Ann Neurol. 1997;41(5):675-82. PubMed PMID: 9153531.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Phenotypic variability in Friedreich ataxia: role of the associated GAA triplet repeat expansion. AU - Montermini,L, AU - Richter,A, AU - Morgan,K, AU - Justice,C M, AU - Julien,D, AU - Castellotti,B, AU - Mercier,J, AU - Poirier,J, AU - Capozzoli,F, AU - Bouchard,J P, AU - Lemieux,B, AU - Mathieu,J, AU - Vanasse,M, AU - Seni,M H, AU - Graham,G, AU - Andermann,F, AU - Andermann,E, AU - Melançon,S B, AU - Keats,B J, AU - Di Donato,S, AU - Pandolfo,M, PY - 1997/5/1/pubmed PY - 1997/5/1/medline PY - 1997/5/1/entrez SP - 675 EP - 82 JF - Annals of neurology JO - Ann Neurol VL - 41 IS - 5 N2 - We studied genotype-phenotype correlations in a group of 100 patients with typical Friedreich ataxia (FRDA), and in three groups of patients with atypical clinical presentations, including 44 Acadian FRDA, 8 late-onset FRDA (LOFA), and 6 FRDA with retained reflexes (FARR). All patients, except 3 with typical FRDA, carried two copies of the FRDA-associated GAA triplet repeat expansion. Overall, the phenotypic spectrum of FRDA appeared to be wider than defined by the currently used diagnostic criteria. Our study indicated the existence of several sources of variability in FRDA. Patients with larger GAA expansions tended to have earlier onset and were more likely to show additional manifestations of the disease. Mitotic instability of the expanded GAA repeats may partially account for the limited degree of correlation between expansion sizes as determined in lymphocytes and clinical parameters. Some clinical variants associated with specific FRDA haplotypes, such as Acadian FRDA and FARR, turned out to be unrelated to expansion sizes. No polymorphism in the frataxin coding sequence could be associated with these clinical variants. SN - 0364-5134 UR - https://www.unboundmedicine.com/medline/citation/9153531/Phenotypic_variability_in_Friedreich_ataxia:_role_of_the_associated_GAA_triplet_repeat_expansion_ DB - PRIME DP - Unbound Medicine ER -