To elucidate the association of frataxin with the pathophysiology of diabetes, we evaluated the mRNA levels of frataxin in leukocytes of patients with type 2 diabetes (T2D).
The main conditions combining diabetes and cerebellar ataxia are Friedreich ataxia, ataxia associated with anti-GAD antibodies, autoimmune polyglandular syndromes, aceruloplasminemia, and cerebellar ataxia associated with hypogonadism (especially Holmes ataxia/Boucher-Neuhäuser syndrome).
In compound heterozygotes, expression of partially functional mutant frataxin delays age of onset and reduces diabetes mellitus, compared to those with no frataxin expression from the non-expanded allele.
The inability to produce normal levels of the mitochondrial protein frataxin causes the hereditary degenerative disorder Friedreich's Ataxia (FRDA), a syndrome characterized by progressive gait instability, cardiomyopathy and high incidence of diabetes.
In conclusion, a heterozygous expansion of the X25/frataxin GAA repeat in healthy individuals is associated with insulin resistance and might be considered a genetic co-factor in the pathogenesis of mitochondrial subtypes of diabetes.
Friedreich's ataxia patients are generally homozygous for the long repeats and exhibit diabetes as pronounced comorbidity.Ristow et al. recently reported an association between the intermediate-length normal allele in the frataxin gene and type 2 diabetes.