Friedreich's ataxia (FA) is one of the genetic syndromes sometimes associated with diabetes and the most common
hereditary ataxia. It is a autosomal recessive
neurodegenerative disease, caused by a mutation in the FRDA gene, which originates decreased expression of
frataxin, a
mitochondrial protein involved in
iron metabolism. The disorder is usually manifest in childhood and is characterised by
ataxia,
dysarthria,
scoliosis and feet
deformity. About two thirds of patients have
hypertrophic cardiomyopathy, 10% have diabetes and 20% have another
glucose homeostasis disorder. Both
insulin resistance and beta-cell dysfunction are implicated in this patients' diabetes pathophysiology. The mean half-life
is 35 years. Cause of death is usually related to
cardiomyopathy or
diabetes' complications. We report the case study of two twin sisters with 28 years old, in whom FA was diagnosed in the first decade, both of them with diabetes since their early twenties. A third sister with FA is reported, with no
glucose homeostasis disorder. They also have two healthy male brothers. Based in this cases, the FA associated diabetes pathophysiology is discussed, concerning the therapeutic approach to these patients and to their diabetic relatives without
neurologic symptoms. The role of molecular genetic testing and genetic counselling are also debated.