Background: Friedreichs ataxia (FA) is an autosomal recessive neurodegenerative disorder characterised by progressive ataxia with limb muscle weakness, absent lower limb reflexes, extensor plantar responses, dysarthria, decreased vibratory sense and proprioception. The most common molecular abnormality is a GAA trinucleotide repeat expansion in intron 1 of the frataxin (FXN) gene. Patients with FA are at risk of getting increased blood sugar levels, or glucose intolerance, and around 20% progress to overt diabetes mellitus (DM). The cause of diabetes in FA is poorly understood. Glucose intolerance and diabetes can result from a shortage in insulin secretion by the insulin-producing β cells in the pancreas, from insulin resistance, or from a combination of both.
Case: A 15.5-year-old girl was admitted to the hospital with the complaints of weight loss, polyuria and polydipsia of 1-month duration. History revealed the presence of gait disturbance and pain in her soles for the last 3-years. Neurological examination demonstrated ataxic gait pattern, pes-cavus, intentional tremor, lower limb areflexia and fleksor plantar response. Thyroid gland was soft, and bilaterally 4 cm on palpation. Hyperglycaemia (390 mg/dl) had been detected on laboratory and further tests showed ketonuria, insulinopenia (1.53 μIU/ml), c-peptide of 1.08 ng/ml (N: 1.15) and HbA1c of 13.4%. Basal and bolus insulin treatment had been initiated. Diabetes autoantibodies (anti-insulin, -GAD, and -islet cell antibodies) were negative. Echocardiography were normal. Hyperthyroidism was detected (TSH: 0.03 μIU/ml (0.345.6), fT4: 1.79 ng/dl (0.611.12), fT3: 4.57 pg/ml (2.53.9)) with negative thyroid autoantibodies. Thyromasole was added to treatment. FTX gene analysis revealed homozygous >66 GAA tri-nucleotide repeats in intron 1 (N: -), which is consistent with FA.
Conclusion: FA should be considered in patients who presented with diabetes and ataxia. Non-autoimmune hyperthyroidism detected in this patient is a novel finding in FA.
01 Oct 2015 - 03 Oct 2015