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Friedreich's Ataxia - Clinical

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FRIEDREICH'S ATAXIA (freed'rikes at'aksy'uh)

nb. italics are used to explain or expand clinical description
This is a clinical description, which I have edited, and reformatted. I have added the Italic notes, and the footnote. Friedreich's Ataxia encompasses variations due to individual responses to the key disease effects. These effects are noted below and are common to all sufferers, although the intensities and chronology is widely variable,

A multisystem disorder characterized by progressive ataxia and neurological, cardiac, musculoskeletal, and endocrine manifestations.

  1. incidence: 1/100,000 live births (average Caucasian)
    Canada 1/37,000, US 1/50,000, Italy 1/22,000, Japan below 1/1,000,000, Africa ~ unknown
  2. age of onset: usually prior to 10 years of age (but as late as 16 years)
  3. risk factors: familial - autosomal recessive
  4. chrom.#: 9q13-q21.1
  5. gene: frataxin

    clinical features similar in members of same family
    by chronology of symptoms but not necessarily by rate of progression
    heterozygotes are phenotypically normal
    this is a fancy way of saying the gene behaves in a typical single gene recessive manner, ie. 1 in 4 offspring of carriers etc.

PATHOGENESIS: nb. read '->' as 'leading to..'
genetic defect -> impaired expression of frataxin -> accumulation of iron within the mitochondria of affected cells -> production of free radicals within the affected cells -> cell death -> phenotypic expression in the nervous system (CNS and peripheral nerves), cardiac tissue and pancreas

phenotypic indicates that the effect is identical between sufferers at least at cell level, although the effects at individual level are often quite diverse

  1. Neurological Manifestations
    1. Ataxia (unsteadiness)
      initial presentation in 95% of cases slowly progressive -> loss of ambulation within 20 yrs
    2. Cerebellar Dysfunction
      1. dysarthria (explosive) - speech becomes hard to synchronize
      2. dysdiadokokinesia - fast or complex motion difficult
      3. finger-nose ataxia - next doctor who asks this, I'll poke HIS eyes!
      4. Dysfunctions more common & severe in the lower limbs than upper limbs
      5. head titubation - head wobble
      6. ocular dysmetria - the doctor moves a finger before the subject eyes and observes the eye movement. Dysmetria is overshooting, misdirection, and wobbling of gaze direction, causing Nystagmus, double vision, and wandering focus. (and all BEFORE you hit the scotch!)
      7. positive Romberg test - while still able to stand, get subject to stand, legs together, then close eyes. the positive result refers to sight balance remaining whilst ear balance has failed. ie. closey eyes, fally over.
      8. Reflexes absent - deep tendon reflexes - extensor plantar reflex
        note here that since a gene test has been in use, some people with hyper reflexes have been re-classified as FARR Friedreich's ataxia with retained reflexes. Hyper reflexes also occur in many SCAs (spinocerebellar ataxias)

    3. Sensation
      1. loss of vibration and position sense
      2. impaired light touch and pain sensation - variable between none and hyper on same subject, ie. most of us suffer cuts unnoticed, but can't tolerate a lentil in a shoe. I ripped a toenail off, and did not notice

    4. Others
      1. normal intelligence
      2. neurosensory hearing loss - cannot separate voices from background sounds, for example
      3. muscle weakness in hands and feet - inability to determine pressure, I have watched a pen fall from my fingers in disbelief whilst my perception was that I had it gripped

  2. Cardiac Manifestations
    Hypertrophic Cardiomyopathy (in 90% of patients)
    1. systolic ejection murmur - you need a doctor with a stethoscope for this one (or a nurse with black stockings!)
    2. SOBOE, palpitations, chest pain (angina), arrhythmias, congestive heart failure, death
      SOBOE = Shortness Of Breath On Exertion.
      Congestive heart failure and Sudden Cardiac death are the major cause of death in FA. The usually quoted average life span is 37 with most deaths in the teens and early twenties who account for around half FA deaths

  3. Musculoskeletal Manifestations
    1. hammer toes
    2. pes cavus (high-arched feet)
    3. progressive kyphoscoliosis - hunch back which can affect breathing
      my speculation is that all of these, and the cardiomyopathy are the result of inability to relax muscles, which shorten, and cause bad heart function, walking on toes (heels off ground) curled fingers etc. Please comment on this hypothesis

  4. Endocrine Manifestations
    1. insulin dependent diabetes mellitus
    2. onset in 3rd decade in 10-20% of patients

  1. Evoked Potentials
    abnormal auditory brainstem, spinal somatosensory, visual evoked potentials

  2. EMG
    slowed nerve conduction velocities in affected limbs

  3. ECG
    reduced T wave amplitude, RVH and/or LVH, arrhythmias

  4. Imaging Studies
    x-rays to follow musculoskeletal manifestations

  5. Serum
    abnormal glucose tolerance test, hyperglycemia

  1. Supportive
  2. no treatment available to stop progression of disease

  3. symptomatic treatment of various manifestations


The above is a definitive overview of FA and includes both early and late symptoms, most of which an FAer will suffer sooner or later. Personally I don't yet have diabetes, nor kyphoscoliosis. Also my eyesight is fine, but my arms are getting too short to read a book! Most of the rest I have to some degree. I have used a wheelchair since about 1985 and indoors since 1991 about when I stopped driving. My last nine years driving was with hand controls. I could not carry a cup of drink unspilt from 1970 diagnosed 1978 at first visit to 'neuro' (a very rare result apparently!) But still had the tests to confirm. It is an easy diagnosis, but very few doctors are aware of it. There is a gene test now, but the symptoms above are easily checked and the seven Neurological symptoms define it distinctly, although they may not all appear at first, but are usually present before 16 years of age. The lack of reflexes tends to be our first symptom. (except those with FARR)

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Updated: 26 October 2002 . . . Checked: 11 Sept 2002