by André Delacourte

General outline

Familial prion disease

Symptoms and course

GSS encompasses a diverse clinical spectrum ranging from progressive cerebellar ataxia or spastic paraparesis (both usually in combination with dementia), to isolated cognitive impairment resembling Alzheimer's disease.

The average age of onset is 46 years and the average duration of the disease is 60 months. GSS usually starts with clumsiness, unsteadiness and shakiness, together with rigidity in the limbs. Dementia sets in later and the patient may survive for several years.

Causes and risk factors

Due to different types of mutations on prion genes such as P102L, P105L, A117V, G131V, F198S, D202N, Q212P, Q217R, M232T.

Diagnostic procedures

For people with symptoms of GSS, the investigations are the same as for any other prion disease. However, in addition, a simple blood test should confirm the presence of a PrP gene mutation. EGG often but not always show characteristic changes. MRI will be done to eliminate other conditions such as a tumour. Blood and other biochemical tests are likely to be normal. The only definite diagnosis comes by post mortem. However in the case of inherited prion disease, the family history of neurological disease will be a very important pointer in the diagnosis.

Post-mortem examination: multicentric amyloid plaques stained with antibodies against prion protein.

Available services

National CJD Surveillance Unit Western General Hospital Crewe Road, Edinburgh EH4 2XU Scotland www.cjd.ed.ac.uk

In addition to surveillance and research they can organise intensive support for the person with CJD and their family.

Human BSE Foundation A charity set up by and for people who have been affected by vCJD. www.hbsef.org grahamsteel@hbsef.org

CJD Support Network Gillian Turner Birchwood, Heath Top, Ashley Heath Market Drayton Shropshire, TF9 4QR England www.cjdsupport.net

Prion Clinic Department of Neurology St Mary’s Hospital, Praed St. London, W2 1NY United Kingdom

References

• Kovacs et al, Mutations of the prion protein gene. Phenotypic spectrum. J. Neurol (2002) 249:1567-1582.