Imran Haque And The Happenings With The Human Genome: CRISPR 2.0November 29, 2017
Medical technology and practices have been advancing at an incredible rate over the past few decades, and one of the premier breakthroughs in the space is CRISPR. At a high level, CRISPR is a process that allows editing DNA sequences and gene function, which opens up a world of possibilities when it comes to developing new medicine and treatments. However, CRISPR as we know it today is not a perfectly precise tool, as it requires the rewrite of entire subsections of DNA or a genome. A new breakthrough in a joint study by Harvard and MIT has resulted in a new process called base editing, which gives researchers the ability to edit minute portions of DNA. In other words, if a single word needed changing in a paragraph, CRISPR would require rewriting the entire paragraph with one word changed while base editing would allow changing the specific word itself.
To help us understand the implications of base editing will be Dr. Imran Haque, an internal medicine specialist and general practitioner based out of Asheboro, North Carolina. Dr. Imran Haque is very excited about base editing because of the tremendous implications it has on the future of treating genetic diseases. Today, treating genetic diseases often requires a minute change in the patient’s DNA, but implementing that change is incredibly difficult. Dr. Imran Haque will be relying on his experience of 15 years as a doctor to help explain exactly how base editing, or CRISPR 2.0, can revolutionize the way genetic diseases are treated and how it can ultimately lead to more effective medicine.
The Human Genome
The human genome contains billions of proteins that have been categorized into different letters: A, C, G, and T. Each of these letters pair off to form the iconic double strand in DNA – A with T and C with G. Every day, the DNA replicates itself many times each day, but the process is not always perfect. Errors called “Point Mutations” can occur, where a single letter pair could be swapped, deleted, or erroneously inserted. Point mutations can seem like a small problem at first, but it’s important to realize that the issue will snowball and have huge implications down the line as the incorrect DNA will replicate over time. In fact, Dr. Imran Haque points out that point mutations are the largest cause of genetic diseases in people, where 32,000 of 50,000 changes in the human genome are directly attributable to point mutation.
The Strength of Base Editing
Handling point mutations is the strength of base editing. When a point mutation is discovered today, targeting the exact incorrect letter pair is a laborious process. Even with CRISPR, making a minute change requires removing out the entirety of the DNA strand and replacing it with a new DNA strand that has no point mutation, much like replacing an entire paragraph of text to change one word. Base editing, on the other hand, allows researchers to directly target the erroneous base pair, a much more precise and less invasive process. In fact, a study conducted by a David Liu, a Harvard chemistry professor and member of the Broad Institute, found that it was possible to directly target and swap DNA letter A into G without affecting the rest of the DNA strand. In other words, he was able to change an A-T base pair into a G-C pair in one stroke, something that has been much more difficult without base editing. Dr. Imran Haque believes that base editing will become an extremely valuable tool in the arsenal of medical practitioners around the world – the goal of the base editing is not to replace CRISPR, but to be a more specialized tool applicable for certain diseases. While CRISPR is like a pair of scissors, base editing is more like a pencil.
The Implications of Base Editing
The vast majority of genetic diseases rise as a result of point mutations – 32,000 of 50,000 genetic diseases are attributable to point mutations. Being able to precisely target the letter pair that was copied erroneously will be a huge asset in treating a wide variety of genetic diseases. Base editing already existed in a limited capacity today – the ability to switch G into A, and that letter swapping combination accounts for about 15% of disease-related point mutations. The ability to switch G to A has already been used in practice to cure diseases such as anemia, but that is just a first step towards the right direction. Using the base editing process found by Liu, Dr. Imran Haque believes that a tremendous of diseases can be tackled and cured. In fact, Liu’s research team has already used their base editing tool to correct a number of point mutation-induced diseases. Hereditary hemochrotasis is a disorder that causes the body to absorb an excess of iron, which can lead to liver diseases, heart problems, and diabetes in the future – and that’s just one example of a disease that Liu has used base editing to suppress. Liu is also conducting research on how base editing can be used to cure blood diseases, hereditary deafness, hereditary blindness, and neurological disorders.
Base Editing is a step Towards the Future of Treating Genetic Diseases
Dr. Imran Haque looks forward towards a future of more effective medicine, and he believes that base editing is a direct answer to treating many hereditary genetic diseases. Being able to edit specific base pairs in the DNA was previously a cumbersome task that had possibility of side effects, and base editing introduces the ability to directly edit the problem area without touching other parts of the DNA strand. In addition, being able to catch, minimize, and treat certain genetic conditions caused by point mutations will lead to cheaper overall healthcare, as the cost of treatment is no longer greatly extended. Ultimately, base editing is a step forward for medicine, especially in the realm of treating genetic diseases.