Corticosteroid therapy is a potential therapeutic treatment for patients with Friedreich ataxia (FRDA) and nephrotic syndrome, according to a study titled “Friedreich Ataxia and nephrotic syndrome: a series of two patients,” published in the journal BMC Neurology.
FRDA is a genetic, progressive, neurodegenerative disorder that causes damage to the nervous system and leads to impaired muscle coordination (ataxia). The disease, caused by the lack of the frataxin protein, can also cause scoliosis, urinary dysfunction, diabetes mellitus, optic atrophy, hearing loss, sleep apnea, and hypertrophic cardiomyopathy.
Nephrotic syndrome is a disorder that can sometimes be associated with FRDA. Researchers report two cases of individuals burdened with both conditions, strengthening a possible connection between these two diseases. One of the patients, a 13-year-old girl diagnosed at age 5 with FRDA, exhibited significant improvements upon corticosteroid treatment.
She did not have epilepsy, a link previously identified in a patient with nephrotic syndrome and FRDA. She was diagnosed with idiopathic nephrotic syndrome at age 7 by testing protein urine concentration (no renal biopsy was performed).
The young teen was treated with prednisone pulse therapy at 30 mg daily, and protein levels rapidly normalized in the urine. Her neurologic symptoms also improved through the steroid treatment, including control of her heel cords and hamstrings, and she regained her skills in balance as related to single-leg stance over the course of a year. Following a second steroid treatment, the patient had less fatigue and higher endurance.
The second patient was a 25-year-old male of Indian descent diagnosed with FDRA at age 10 and previously diagnosed with nephrotic syndrome when he was 2 years old, also by urine protein testing. He was treated with chronic steroids from age 2 to 10 but showed no improvement. His nephrologist switched the steroid treatment for cyclophosphamide over three months (at 100 mg) and the patient experienced no nephrotic syndrome relapses. However, his ataxia worsened following cessation of steroid therapy.
With the improvements observed in the first patient, researchers reviewed data from Children’s Hospital of Philadelphia (CHOP) and the Collaborative Clinical Research Network (CCRN) to look for patients reporting responses to corticosteroids: nine FDRA patients experienced improvements in balance, gait or speech with corticosteroid treatment and with other immunomodulatory therapies without steroid-induced worsening.
“The catabolic effect of steroids could provide a mechanism for the improvements seen in FRDA, as altered lipid metabolism has been documented in rat myocytes with diminished frataxin levels and in Drosophilia melanogaster. The present patient, taken with previous basic and scientific research, suggests the importance of pilot studies examining the efficacy of pulse steroid treatment as a potential therapy in FRDA,” the authors concluded in their study.