Clinical features

Majority of patients (about 75%) present with typical Friedreich's ataxia:

• mean age of onset of symptoms is 10 to 15 years
• neurologic manifestations
  • gait ataxia
  • earliest symptom in vast majority of patients
  • limb ataxia
    • is an early feature of the disease
    • result in difficulty with handwriting, washing, dressing, use of cutlery and carrying drinks or food
  • absent lower limb reflexes
    • is an early sign present in almost all patients and reflects the underlying peripheral neuropathy.
  • weakness and wasting
    • a relatively late sign
    • more prominent in the lower limbs compared to the upper limbs
  • peripheral sensory neuropathy
    • reduced/absent vibration sense and proprioception
  • spasticity
  • visual disturbances
    • optic nerve atrophy – seen in around 25% of patients, often asymptomatic
    • abnormalities of eye movements e.g. - square wave jerks; abnormalities of saccades, pursuit, fixation
  • dysarthria
    • present in more than 90% of individuals
    • is an early sign
  • hearing loss
    • found in 8% to 13% of individuals
  • dysphagia
    • is common and present in around 92% of individuals with FRDA
  • cognition
    • cognition is generally not affected
    • there can be impairment in verbal fluency, visuoconstructive and visuoperceptual capacity, and motor and mental reaction times
• non neurological features
  • cardiac complications
  • hypertrophic cardiomyopathy
  • abnormal electrocardiogram
  • diabetes mellitus
  • skeletal abnormalities
    • scoliosis
    • foot abnormalities - pes cavus, talipes equinovarus
  • sleep disordered breathing and sleep apnoea
  • urinary frequency and urgency (1,2,3)

Atypical presentation is seen in 25% of patients with FRDA e.g. -

• late-onset FRDA (LOFA) and very late-onset FRDA (VLOFA)
  • onset is later than age 25 years
    • in LOFA, the age of onset is 26-39 years while in VLOFA, the age of onset is over 40 years
• FRDA with retained reflexes (FARR)
• FRDA in Acadian
  • have a later age of onset and of wheelchair confinement, and a much lower incidence of cardiomyopathy (1,2,3)

Reference:

• (1) Bidichandani SI, Delatycki MB. Friedreich Ataxia. 1998 Dec 18 [Updated 2014 Jul 24]
• (2) Delatycki MB, Corben LA. Clinical Features of Friedreich Ataxia. Journal of child neurology. 2012;27(9):1133-1137
• (3) Parkinson MH et al. Clinical features of Friedreich's ataxia: classical and atypical phenotypes. J Neurochem. 2013;126 Suppl 1:103-17