The fatal brain disease Creutzfeldt-Jakob disease (CJD) is caused by infectious agents known as prions which are composed of rogue proteins that can grow and spread in the brain. One of the well-known ways people have become infected with prions is following treatment (usually during childhood) with human growth hormone prepared from pituitary glands removed from deceased people, some of whom may have had a prion infection. This type of treatment stopped many years ago (in 1985 in the UK) when the risk of it causing CJD came to light, but several people a year continue to develop this form of CJD because prion infections can take decades to develop. The MRC Prion Unit has been conducting a long-term clinical study on prion diseases in the UK as part of its research to develop effective treatments for these conditions. In the course of this research, we perform detailed studies on brain samples where patients and their families consent to donate tissue for our research. Recently, we looked at eight patients who had developed CJD after treatment with growth hormone. Surprisingly, we found that four had significant or severe changes in their brains normally seen in Alzheimer’s disease (AD) which are very rarely seen in patients of this age group. Two others had more localised changes and only one of the eight had none. These changes are the build-up of protein deposits known as amyloid-beta (or Aß for short). We also showed that pituitary glands from patients that had Aß in their brains often also contained Aß, so we think that Aß as well as prions might have contaminated batches of growth hormone. We and other scientists around the world have suspected for many years that other rogue proteins might sometimes behave like prions and cause disease in a similar way. Indeed experiments from several laboratories have shown that Aß deposits form, after a prolonged period of time, in the brains of some laboratory animals when they are injected with extracts of brain tissue from patients who had died of Alzheimer’s disease. It is therefore thought that Alzheimer protein deposits might act as “seeds” which trigger the formation and spread of more seeds rather like prions do. Up until now there has been no evidence that this has actually happened in humans or whether this would be sufficient to cause Alzheimer’s disease. These new findings suggest transfer of such seeds from some batches of growth hormone to humans has occurred although we do not know whether the protein deposits we saw in the brains would have led on to the full picture of Alzheimer’s disease had these patients lived longer and not died of CJD.
Our findings relate to the specific circumstance of cadaver-derived human growth hormone injections, a treatment that was discontinued many years ago. It is possible our findings might be relevant to some other medical or surgical procedures by which CJD can rarely be transmitted, but evaluating what risk, if any, there might be requires much further research.
There is absolutely no suggestion from our work that AD is a contagious disease or that there would be any risk to relatives, spouses or carers of patients with AD. Studies in the past have not found any association between AD and blood transfusion.
This work does however contribute to the growing research interest in parallels between prion disease like CJD and Alzheimer’s disease and whether they may share features that might provide insights to advance diagnosis, prevention and treatment in the future.
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Commonly asked questions
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The National Prion Clinic (NPC) is the national referral centre for prion disease and is part of the University College London Hospitals NHS Foundation Trust (UCLH). It is funded by the NHS to provide diagnosis and care for patients with, or suspected to have, any form of human prion disease (Creutzfeldt-Jakob disease, CJD). The clinic is integrally linked with the MRC Prion Unit at the Institute of Neurology, a Postgraduate Research Institute of University College London. The NPC provides diagnosis and care for all forms of prion disease (inherited, iatrogenic, sporadic and variant CJD). We aim to review new patients within a week of referral. The NPC also plays a key role in facilitating research to promote early diagnosis and the development of potential therapies.
The following sections provide information on prion disease, the services we offer and research into prion disease (CJD).
Open Day feed back form
Thank-you for attending the open day held on 29th January. We really value the time taken to complete the feed back form. The responses were overall very positive, it is important that you feel supported in your role as a patient/carer. We would like to hear if you have ideas about how our service could be improved and how to support you in this role. We will also be sending out questionnaires to everyone that attended the open day.
Once again thank-you for taking the time to complete the feedback form, feel free to offer any further feed-back directly to your Nurse or Doctor, or via the Prion-help contact email address: firstname.lastname@example.org
National Prion Clinic describe a new form of inherited prion disease that causes diarrhoea
Prion diseases usually cause problems with balance and thinking skills due to damage in the brain and other parts of the central nervous system. They are caused by a normal body protein, called the prion protein, changing shape, depositing in brain tissue, and becoming toxic to nerve cells (Background to Prion Disease). The National Prion Clinic team now report the investigation of a new disease in a single large family, caused by a gene mutation. This gene mutation makes a short version of the prion protein and uncouples it from attachment to the surface of cells. The newly identified prion disease is unusual because the symptoms start with diarrhea. The symptoms typically commence when patients are in their thirties, and then over the next 10 years the symptoms gradually progress and involve loss of sensation in the feet, and low blood pressure on standing. It is only 20 years later that problems with thinking skills start. Deposits of abnormal prion protein were found throughout the body, for example, in the gut, nerves, heart, and lungs. Doctors should now be aware that if they have a patient with unexplained diarrhea and signs of a neuropathy it’s worth checking the prion protein gene for abnormalities.
National Prion Clinic develop a new way to measure progression in prion disease: the MRC Scale
The National Prion Clinic team have developed a rating scale for prion diseases, that will have major implications in future treatment trials. In a paper published in the top neurological scientific journal Brain, the team describe a precise way to track how patients with prion disease are progressing.
The use of the MRC Prion Disease Rating Scale or “MRC Scale” in short form, in the National Monitoring Prion Cohort has revealed there are three distinct patterns of change: 1. slow progression associated with genetic forms of disease, 2. rapid progression associated with any form of the disease, and 3. a proportion of patients that survive in a comatose state sometimes for prolonged periods of time.
The paper is based on follow-on work from a MRC funded clinical trial PRION-1 (2004-2007), using the anti-malarial drug – quinacrine, which concluded that there was a need for a definitive prion disease rating scale. The PRION-1 study raised lots of questions, in particular about how to measure the progress of patients through the disease. Some rating scales we have used in the past were poor at measuring patient progression, though questions about every-day activities seemed to match clinical reality. The new rating scale is based on interviews with 71 families, we’ve taken into account the experience of the disease from the perspective of patients, their relatives and carers to find out what are the important symptoms of the disease. Questions focus on speech, memory, continence, mobility and self-care, which are all important aspects of how the disease impacts on families. We appreciate and acknowledge the contribution of carers and relatives to this research work.
The Science and Technology Committee held an oral evidence session on variant Creutzfeldt-Jakob Disease (vCJD) and the ongoing risk it poses to the UK at which Prof. John Collinge gave evidence.
Briefing note for patients, carers and health professionals