Ataxia in children: Case

This boy has Friedreich ataxia. The cardinal constellation is a progressive limb and gait ataxia over two years in a teenager, with scanning speech and clumsiness of the hands, absent knee and ankle reflexes, extensor plantar responses, loss of position and vibration sense in the lower limbs, bilateral pes cavus, a thoracic scoliosis, and a hypertrophic cardiomyopathy on the echocardiogram. The onset is in adolescence and before twenty-five, and the combination of absent lower limb reflexes with an extensor plantar response and dorsal column loss is the signature that separates Friedreich ataxia from a pure cerebellar lesion. The diagnosis is confirmed by the targeted genetic test for the GAA trinucleotide repeat expansion in the FXN gene, and the condition is the most common inherited ataxia in populations of European descent, inherited in an autosomal recessive pattern.

Confirming the diagnosis and the mechanism

The clinical picture alone makes the diagnosis highly probable, and the confirmatory test is the genetic test for the GAA trinucleotide repeat expansion in the FXN gene on chromosome nine. Friedreich ataxia is autosomal recessive, and the GAA repeat expansion reduces the production of frataxin, a mitochondrial protein that assembles iron-sulphur clusters for the electron transport chain. The loss of frataxin starves the metabolically demanding neurons of the dorsal root ganglia and the dorsal columns, and the cardiomyocytes of the heart, which is the single mechanism that produces the sensory ataxia, the loss of position and vibration sense, the cardiomyopathy, and the diabetes. I would arrange the FXN genetic test as the first and definitive investigation, and I would perform a magnetic resonance imaging to document the cerebellar and spinal cord involvement and to exclude a structural lesion, though the genetic test is the diagnostic anchor. [5]

The cardiac and endocrine surveillance

The cardiomyopathy is the leading cause of death in Friedreich ataxia, so the cardiac surveillance is the single most important systemic element of the plan. I would refer him to cardiology for a baseline and serial echocardiography and a cardiology opinion on the hypertrophic cardiomyopathy, and I would monitor for arrhythmia. I would screen for diabetes with an annual fasting glucose and glycated haemoglobin, because diabetes mellitus is part of the multisystem disease and affects the prognosis and the management. The scoliosis warrants orthopaedic assessment and monitoring for progression, and the pes cavus may need podiatry input. [10]

The disease-modifying therapy and the broader care

I would refer this boy to a Friedreich ataxia or a neurology service for consideration of omaveloxolone, the first disease-modifying therapy for the condition. The MOXIe trial showed that omaveloxolone, which activates nuclear factor erythroid 2-related factor 2 and restores the antioxidant and mitochondrial defences that frataxin loss impairs, improved the modified Friedreich Ataxia Rating Scale score compared with placebo, and a delayed-start analysis confirmed a durable benefit, which supports treating early. The natural history study by Rummey and colleagues documented the heterogeneity of neurological progression, which has consequences for the prognosis and the trial design, and the 2025 Lancet Neurology review by Reetz brought the multisystem burden and the therapeutic horizon up to date. [7] [6] [11]

The broader care, framed by the clinical management guidelines of Corben and colleagues, is multidisciplinary. I would arrange physiotherapy to preserve mobility and balance and the timely provision of walking aids and, ultimately, a wheelchair, occupational therapy for the activities of daily living, and speech therapy for the dysarthria. I would address the psychosocial impact of a chronic progressive genetic diagnosis on a teenager, with attention to his mental health, his education, and his future planning. [10]

Genetic counselling, prognosis, and follow-up

I would arrange genetic counselling for the autosomal recessive inheritance, which explains that both parents are carriers and that each sibling has a one in four chance of being affected, and I would offer carrier testing to his younger sister with appropriate counselling. The reproductive options, including prenatal and preimplantation genetic diagnosis, are discussed with the family and the genetic service. The prognosis is that of a progressive degenerative disease, with loss of ambulation typically within ten to fifteen years of onset and a reduced life expectancy driven by the cardiomyopathy, though the natural history is heterogeneous and the arrival of omaveloxolone offers the prospect of slowing the neurological decline, particularly when started early. I would plan the transition of care to the adult neurology and cardiology services as he approaches adulthood, with the goal of preserving function, communication, and quality of life. [5] [6]