Friedreich ataxia

Friedreich ataxia (FA) is the most common inherited progressive ataxia. It carries an autosomal recessive inheritance ¹.

Pathology

The condition results from an expansion of an unstable GAA trinucleotide repeat located in chromosome 9q ^1,6.

In the posterior andlateral columns of the spinal cord there is a loss of myelinated fibers and gliosis 

Associations

• cardiomyopathy ^8-9 : most commonly hypertrophic cardiomyopathy 

Epidemiology

Thought to have an estimated prevalence of ~ 1:50,000. There is no recognised gender predilection.

Patient's typically present in childhood to adolescence. Those with a higher number of repeats (> 500) are thought to present at an earlier age and with signifcantly different clinical features ¹. 

Radiographic features

MRI : Brain / Spine

• may show thinning (reduction in AP diameter) of the cervical spine ²
• cerebral and cerebellar atrophy may also be evident ⁵
• DWI is a suitable non-invasive technique to quantify the extent of neurodegeneration in Friedreich ataxia, that appears more extended than previously reported, showing a microstructural involvement of structures such as optic radiation and middle cerebral peduncle ¹⁰.

Etymology

It is named after Nikolaus Friedreich : German physician (1825-1882)