Abstract

현재까지 사망한 인간광우병 희생자 가운데 처음으로 M/V형 환자로 밝혀진 30세 남성(2008년 6월 입원, 2009년 1월 사망)에 대한 콜린지 박사팀의 사례 보고가 [랜싯]지에 실렸습니다. M/V형은 M/M형에 비해 잠복기가 더 긴 것으로 추정되며, 쿠루의 사례에 비추어 볼 때 잠복기가 수십년에 달할 수 있을 것으로 추정되고 있습니다.

영국의 [인디펜던트]지는 이 보고와 관련된 기사제목을 “과거에 예측했던 사람보다 더 많은 사람이 인간광우병에 감염되었을 수 있다”로 뽑았고… BBC 방송은 30세 남성 그랜트 굿윈(Grant Goodwin)의 실명과 사진을 공개했습니다. 영국의 166번째 vCJD 사망자 그랜트 굿윈씨는 처음으로 M/V형 프리온 유전자형을 가진 인간광우병 감염자로 밝혀졌으며, 전문가들은 이러한 형태의 감염자가 350명 가량 될 것으로 추정하고 있습니다.

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Case Report

출처 : The Guardian, Friday 18 December 2009
http://www.guardian.co.uk/science/2009/dec/18/vcjd-creutzfeldt-jakob-human-incubation

More people may be incubating variant CJD, the human version of so-called “mad cow disease”, than was previously thought, according to scientists who today report an unusual case of the disease. All those tested worldwide since 1994 when the first cases were identified have been MM homozygous.

However, a 30-year-old man who died of vCJD in January this year was found to have a different genetic makeup from the rest of the 200 or so people diagnosed around the world. Six months before the man was diagnosed with the disease, he had been admitted to hospital with personality changes, unsteadiness in walking that became progressively worse and intellectual decline. He told doctors he had severe leg pain and memory problems. Two months later, he developed visual hallucinations. The symptoms got progressively worse and an MRI scan confirmed vCJD. The symptoms and the course of the illness were not unusual for vCJD, but the man had a different genetic makeup from the rest of the 200 or so people diagnosed around the world to date.

Variant CJD is caused by prions, infectious agents which are made up mainly of proteins. The same prions cause vCJD and also BSE – bovine spongiform encephalopathy – which was dubbed “mad cow disease” because cattle who contracted it staggered when they tried to walk. Prion diseases affect the structure of the brain or other neural tissue and are currently untreatable and fatal.

Doctors from the MRC Prion Unit and National Prion Clinic at the UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery in London, report the unusual case in today’s Lancet medical journal. Tests showed that the man had a particular form of the human prion protein gene. All those tested world-wide since 1994 when the first cases were identified have been MM homozygous. However, this patient was MV heterozygous.

The observation could be of concern. In some other human prion diseases, such as kuru – thought to be linked to cannibalism in Papua New Guinea – people who are MV heterozygous have incubated the disease for longer than those who are MM homozygous before symptoms have shown. Some MV heterozygous patients are reported to have incubated kuru for over 50 years.

It is possible, doctors say, that vCJD takes longer to develop in people who are MV heterozygous than in MV homozygous people.

“The majority of the UK population have potentially been exposed to BSE prions but the extent of clinically silent infection remains unclear,” say the authors of the paper. About a third of the population have the MM homozygous genotype – and until now all the cases came from this group. If individuals with other genotypes are similarly susceptible to developing prion disease after exposure to BSE, further cases would be expected, they say. However, they add, it is possible that susceptibility to vCJD and incubation period may be influenced by other genetic factors which have not yet been identified.

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CJD victim ‘had different gene’

It is thought Grant Goodwin incubated the illness from early childhood 출처 : http://news.bbc.co.uk/2/hi/health/8419459.stm A 30-year-old man thought to have died in January from vCJD belonged to a genetic group that had not shown any signs of the disease, scientists say. In the UK, 166 people have died of variant CJD, linked to eating BSE-infected beef, and all were thought to have shared a certain gene. Writing in the Lancet, the scientists say Grant Goodwin, of Lanarkshire, had a different version of the gene. They estimate that up to 350 people in this group could get vCJD. Scientists have always thought that a second wave of vCJD cases would emerge some time after the first. This is the first indication that this theory is being born out with the identification of the first probable vCJD patient outside of the initial genetic group, BBC science correspondent Pallab Ghosh reports. Thomas Goodwin believes his son Grant was incubating the disease for much of his life It is probable because the diagnosis is based on observations of the progression of the disease rather than post-mortem tests which would have provided absolute confirmation of the disease, he adds. The case report written by Professor John Collinge, of the National Prion Clinic, and colleagues is a reminder that the disease has not gone away. Many thousands of people may be carrying the infection and although they will never show any symptoms, they have the potential to infect others. The majority of the UK population have potentially been exposed to BSE prions but the extent of clinically silent infection remains unclear Professor John Collinge, National Prion Clinic Father speaks about son’s decline vCJD is caused by infectious agents called prions. Prion diseases affect the structure of the brain or other neural tissue and are currently untreatable. Disease-causing prions are thought to consist of abnormally folded proteins, which spread by encouraging the normal healthy prion protein found on the surface of most cells in the body to change shape. Tests showed that Mr Goodwin had a heterozygous version of the gene which codes for the human prion amino acids valine (V) or methionine (M). ‘Incubation periods’ People can be V V (homozygous), M M (homozygous) or M V (heterozygous). Since 1994, around 200 cases of vCJD have been identified worldwide, and all those tested have been M M homozygous. However, Mr Goodwin was M V heterozygous. It is thought that 47% of the population have this version of the gene. Professor Collinge said: “The majority of the UK population have potentially been exposed to BSE prions but the extent of clinically silent infection remains unclear. “About a third of the UK population are M M homozygous. “If individuals with other genotypes are similarly susceptible to developing prion disease after BSE prion exposure, but with longer incubation periods, further cases would be expected.” The scientists have previously looked at another prion disease in New Guinea, called kuru, which is induced by eating infected human tissues. The original cases were all M M but more recently M V have appeared. They say this indicates that M V people can get prion diseases like kuru but have a much longer incubation period. A Department of Health spokesperson said: “”The Spongiform Encephalopathy Advisory Committee (SEAC) have noted this finding, which confirms the need for ongoing vigilance and robust surveillance of CJD. “We are continuing to provide resources for CJD surveillance and research, and the development of a test for vCJD remains a priority.”