Employees at UCSF Benioff Children's Hospital in Oakland were the first in the United States to test genome editing directly in the body of a living person, rather than by injecting previously edited cells into it. The doctors had to take such a risky step because the patient suffered from an incurable genetic disease, from which it was not possible to save him by other means. It is too early to judge whether the doctors managed to defeat the disease, since the first results of experimental treatment should manifest themselves in about two months.
The patient who agreed to the risky treatment was Brian Maddox, who suffers from Hunter's syndrome. This is one of the forms of mucopolysaccharidosis, a rare recessive X-linked genetic disease resulting from a deficiency of a number of enzymes and leading to the accumulation of protein-carbohydrate complexes and fats in cells. As a rule, it manifests itself in a person only when he inherits the defective gene from both parents. The disease gradually begins to affect various organs and tissues, and its symptoms appear already in the second year of a person's life.
Previously, Hunter syndrome was treated exclusively symptomatically, with bone marrow transplantation and artificial enzyme injections. Such supportive therapy is costly to patients and costs more than $ 100,000 a year. Doctors at the Oakland Children's Hospital decided on experimental treatment in the case of Brian Maddox only because he underwent more than 25 operations in his life to remove all kinds of hernias, bone growth into the spinal cord and other unpleasant procedures. Of course, the 44-year-old man was willing to do anything to get a chance to recover.
The main difference between the experimental technique was the fact that the genome was edited directly in the patient's body. Earlier, we recall that editing took place over cells extracted from the body, or even grown separately. Tellingly, instead of the CRISPR gene editing technology popular today, scientists used an alternative - Zinc Finger Nuclease. It involves the introduction into the body of neutralized viruses that carry a coded tool for editing the genome. The instrument is synthesized in liver cells, after which it begins to actively rule the genome of the organism. In this case, it is necessary that at least 1% of liver cells have a correct copy of the required gene. Otherwise, the treatment will be ineffective.
As we said earlier, the results of experimental treatment can be judged no earlier than two months later. Brian Maddox himself is well aware that this experiment may end in nothing, but he still does not lose hope that his life will finally become at least a little more comfortable and easier. According to him, for 15 years he was waiting for scientists to learn how to edit the human genome and be able to save it. Well, we wish this person good luck and hope that the treatment will really benefit him.
Sergey Gray