Friedreich's Ataxia

Question 1

Friedreich’s Ataxia

Genetics

Answer 1

Friedreich’s ataxia is the most common of the early-onset hereditary ataxias.

It is an AUTOSOMAL RECESSIVE, trinucleotide repeat disorder characterised by a GAA repeat in the X25 gene on chromosome 9 (frataxin).

Friedreich’s ataxia is unusual amongst trinucleotide repeat disorders in NOT demonstrating the phenomenon of anticipation.

Question 2

Clinical Features

Answer 2

The typical age of onset is 10-15 years old.

Gait ataxia and kyphoscoliosis are the most common presenting features.

• absent ankle jerks/extensor plantars
• cerebellar ataxia
• optic atrophy
• spinocerebellar tract degeneration

Question 3

What are other features (non neuro) associated with Friedreich’s Ataxia

Answer 3

hypertrophic obstructive cardiomyopathy (90%, most common cause of death)

diabetes mellitus (10-20%)

high-arched palate

Question 4

Management

Answer 4

Management is supportive.

It is important to screen for and manage complications e.g. type 1 diabetes mellitus.

Genetic counselling should be offered to the patient and their family.

Question 5

Diagnosis

Answer 5

Diagnosis is by genetic analysis.