International Journal of Medical Advances and Discoveries

International Journal of Medical Advances and Discovery ISSN 2756-3812 Vol. 1 (1), pp. 001-006, December, 2010. © International Scholars Journals

Full Length Research paper

Clinical and molecular genetic findings in a Friedreich’s Ataxia Tunisian family

Yosr Bouhlal¹, Ghada El Euch-Fayeche¹, Fayçal Hentati¹, Rim Amouri¹

¹ Laboratoire de Neurobiologie Moléculaire et de Neuropathologie, Institut National de Neurologie, 1007 la Rabta Tunis – Tunisia

Accepted 15 November, 2010

Abstract

The most common mutation in Friedreich’s ataxia (FA) is an expanded GAA trinucleotide repeat in the first intron of the FXN (Frataxin) gene. A clear correlation between the size of the expanded alleles and phenotype severity was found as the major determining factor. The objective of this study was to report clinical and molecular data of 10 patients homozygous for pathological FXN GAA expansions. Clinical evaluation was preformed for all the patients. GAA expansions were detected by Tripled Primed PCR (TP-PCR) and GAA allele size was estimated by Long Range PCR (XL-PCR). Clinical features were variable within the same family with no correlation between age at onset, worsening score or tendon reflexes status. All patients were homozygous for the pathological GAA expansions. No obvious relationship was found between the different clinical features and size of GAA repeats. In conclusion, factor controlling phenotypic expression in FA may be related to other factors than FXN GAA expansions.

Key Words: Friedreich’s ataxia, GAA expansion, intrafamilial variability.