Clinical Scenario:
A 13-year-old boy is brought with a 2-year history of progressive unsteadiness while walking. His parents have noticed that he frequently trips and has increasing difficulty walking in the dark. He also has slurred speech.
On examination, he has a broad-based ataxic gait, positive Romberg sign and impaired heel-to-shin testing. Deep tendon reflexes are absent in both lower limbs, while plantar responses are extensor bilaterally. Vibration and joint-position sense are reduced in the feet. He has pes cavus and mild scoliosis.
Which of the following is the most likely diagnosis?
A. Ataxia-telangiectasia
B. Friedreich ataxia
C. Wilson disease
D. Duchenne muscular dystrophy
E. Hereditary spastic paraplegia
Correct answer & Explanation:
Correct answer: B. Friedreich ataxia
Explanation
Friedreich ataxia (FRDA) is the most common inherited ataxia beginning in childhood or adolescence. Typical onset is in the first or second decade, with a mean age of onset around 10–15 years.
The neurological findings in this case are characteristic:
- Progressive gait and limb ataxia → cerebellar and spinocerebellar tract involvement
- Positive Romberg sign → impaired proprioceptive input
- Loss of vibration and joint-position sense → involvement of the dorsal root ganglia/posterior columns
- Absent lower-limb reflexes → peripheral neuropathy
- Extensor plantar responses → corticospinal tract involvement
- Dysarthria → cerebellar involvement
The combination of ataxia + areflexia + impaired proprioception + extensor plantar responses is particularly suggestive of Friedreich ataxia.
Pes cavus and scoliosis are common musculoskeletal manifestations. A major extra-neurological association is hypertrophic cardiomyopathy, which occurs in approximately two-thirds of affected individuals. Diabetes or impaired glucose tolerance can also occur.
Ataxia-telangiectasia would be expected to have features such as conjunctival/skin telangiectasia and immunodeficiency. Wilson disease can cause neurological manifestations but usually has other characteristic hepatic or ophthalmological findings.
Exam pearl
Child/adolescent with progressive ataxia + absent reflexes + loss of vibration/proprioception + extensor plantars ± pes cavus, scoliosis and cardiomyopathy → Friedreich ataxia.
Reference
Bidichandani SI, Delatycki MB, Napierala M, et al. Friedreich Ataxia. GeneReviews®. University of Washington, Seattle. Updated June 26, 2025.
Delatycki MB, Corben LA. Clinical features of Friedreich ataxia. Journal of Child Neurology. 2012;27(9):1133–1137.
