Researchers have developed a highly sensitive assay for early diagnosis of the degenerative neurological condition Creutzfeldt-Jakob Disease (CJD). The assay has been developed by microbiologist Ryuichiro Atarashi of Nagasaki University, Japan, and his team.
CJD is a prion disease, in which an isomer of a common protein known as the prion protein (PrP) takes on an abnormal shape and becomes an infectious variant called PrPSc. This variant is thought to trigger the subsequent malformation of other PrP proteins. Unlike their normal counterparts, PrPSc prions cannot be broken down, and instead accumulate - often clustering in brain tissue.
The pockets of abnormal tissue that result cause brain tissue to develop a sponge-like appearance, and because prion conditions can be spread by affected humans or animals, the diseases are often referred to as transmissible spongiform encephalopathies (TSEs).
One problem that has plagued developers of non-biopsy diagnostic techniques is that it is often difficult to avoid false positives among samples taken from patients with neurodegenerative disorders other than CJD.
So Atarashi and his colleagues used a new assay known as a real-time quaking-induced conversion (RT-QUIC) assay. 'Quaking-induced' refers to in vitro shaking, which researchers believe helps to accelerate the reactions, enabling the assay to produce results more quickly.
The team tested cerebrospinal fluid samples from 18 people with CJD and 35 people with other neurodegenerative diseases. This pilot group produced no false positives, and CJD was correctly diagnosed more than 83 pc of the time.
"This technique allows definitive ante-mortem confirmation of CJD," Nature quoted Atarashi, who added that this is currently difficult because it demands the detection of PrPSc in patients' biopsy specimens, as saying.
The findings have been published online in Nature Medicine.