Patient 1

A 37-year-old woman presented to the ataxia clinic with 1 year of increasing unsteadiness and episodes of recent falls. She had behavioural problems from an early age and had Asperger's syndrome. She had undergone bilateral cataract extraction at the age of 10 years. She also had diarrhoea as a child. She had three older siblings all of whom were well with no other family history of neurological illness.

On examination, she had an ataxic gait, increased tone in all four limbs with brisk reflexes and bilaterally extensor plantars. Despite the absence of tendon xanthomata, the combination of ataxia and early-onset cataracts prompted testing for serum cholestanol. This was significantly raised, in keeping with the diagnosis of CTX. She also had significantly increased urinary bile acids.

MRI of the brain showed diffuse symmetrical high T2 signal changes affecting the deep cerebellar nuclei and extending into the white matter of both cerebellar hemispheres (figure 1). In addition, there were multiple white matter lesions in both cerebral hemispheres, which were largely peripheral. There was mild cerebellar atrophy. The patient was treated with chenodeoxycholic acid (CDA) and statins. On follow-up, she appeared to …