Study of FRDA gene in suspect Friedreich ataxia patients

Friedreich ataxia [FA] is an autosomal recessive disorder. Cause of about 2-4% of disease is a GAA triplet repeat expansion in the one allele and carries a point mutation as the other allele. This study was performed to investigate exons of FXN gene to find point mutations for the first time in Iran. In this descriptive study, 50 patients suspected to FA who referred to Special Medical Center were investigated. Genomic DNA was investigated by different PCR methods, including PCR for intron, Long PCR and PCR for exons of FXN gene. Then, products were sequenced and finally sequences were analyzed by related software. C to G nucleotide in intron 2 nt:825954, and T to C in intron 3 nt:832729 of FRDA gene were observed by sequencing method. Nucleotide G insertion was detected in exon 5a nt: 822225. Our study showed that diagnosis of FA is not simple because of clinical overlapping with other ataxia, some mutations in intron maybe affect on the disease which need more examination, and because of consanguinity marriage in Iran, some patients with homozygote mutation may show FA phenotype

[Clinical and molecular investigation of friedreich ataxia in Iranian patients]

Friedreich ataxia [FA] is an autosomal recessive disorder that caused by the expansion of GAA trinucleotide repeat in the first intron of gene X25 [1]. FA is characterized by progressive ataxia and deep tendon areflexia in the lower limbs, dysarthria, skeletal deformities, Cardiomyopathy, muscle weakness and diabetes mellitus may be also found. Cardiomyopathy occurs in almost patients with FA [2]. Cardiomyopathy is the most cause of death in FA patients [3]. Aim of present study was to evaluate the size of GAA repeat and it's correlation with age at onset and cardiomyopathy in these patients. Long PCR testing subsequently confirmed the diagnosing of FA and by identification of GAA repeat, an inverse correlation between size of repeat and age at onset and cardiomyopathy was found