Protein deficiency and its quantity difference in individuals are the main cause

Medical researchers have been puzzled by the fact that two people with the same pathogenic gene mutation often have different onset time and severity In a recent issue of the biomedical journal Cell, Canadian scientists revealed an important cause of this phenomenon protein defects and their quantitative differences in individuals, laying a foundation for accurately predicting the disease development of patients with genetic diseases Andy Fraser, a professor in the Department of molecular genetics at the Donnell force center at the University of Toronto, said that genetic background - a unique set of DNA letters in each human genome affects the severity of any genetic disease The onset and severity of genetic diseases are quite different For example, people with mutations in the CFTR gene may develop cystic fibrosis, and patients may have breathing difficulties due to the accumulation of mucus in the lungs, or even life-threatening infections However, newborns diagnosed with the disease do not show any signs of the disease until adulthood At present, doctors can only tell patients that they have a certain genetic disease, but can not tell the severity of the disease Fraser says it's a bit like telling someone that there's going to be a car accident, but not whether it's just a minor collision or a car crash Changing this uncertainty will greatly help patients and allow doctors to focus on the most affected patients The mutation of pathogenic gene will destroy the function of gene By changing the sequence of DNA letters, the product protein of gene will eventually be defective, so that it can not complete its work in cells The genetic background will affect the quantity of protein products, just like the dimmer switch to fine regulate genes This means that each person will have thousands of unique proteins in different quantities If a person carries a mutation in a disease causing gene, the defective protein can cause the disease Fraser's team found that if the level of defective protein was just below the threshold, the effect of mutations prevailed, and the disease tended to be more severe By studying the genetic mutation effects of 250000 worms, and verifying the data with human cells, they found the same information: the severity of the disease is the result of protein defects and their number in each individual Fraser said the study found for the first time that it could predict the severity of the disease by measuring the specific individual gene activity of the mutation carrier The discovery could lead to new treatments to reduce the severity of genetic diseases.