CRISPR Gene-Editing Could End Genetic Diseases, But Gene Experts Call for Strict Regulation

With the development and refinement of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Cas9 gene-editing technology, medical science is on the cusp of a new era in which embryonic gene treatments could potentially wipe out heartbreaking and deadly birth defects and hereditary disease.
By on 09/29/2020 2:00 PM

Source: MedicineNet Health News

Want to choose your kid's eye color? How about, maybe, tweak her DNA so she'll be a track star? Even better – make sure it's a "her" or "him," depending on your preference...

Not so fast, say international medical authorities convened to come up with gene editing protocols. Top U.S. and British health authorities together released a report this month on the technical and scientific considerations to embryonic gene editing once new techniques are clinically tested and approved for use – something that has not happened yet in any nation, according to the report.

When embryonic germline gene editing, that is, introducing genetic changes that can be passed down from parent to child, has proven safe in pre-clinical and clinical trials, applying this technology should be limited to couples who cannot otherwise have healthy babies. Furthermore, the clinical practice of germline editing should have a robust, international system of oversight with whistleblower protections, according to the international consortium of medical authorities.

With the development and refinement of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Cas9 gene-editing technology, medical science is on the cusp of a new era in which embryonic gene treatments could potentially wipe out heartbreaking and deadly birth defects and hereditary disease.

But these processes now in development require strict oversight and protocols because the stakes are so high. Embryonic DNA editing errors could haunt families for generations. This is why most of the international medical authorities – from the World Health Organization and various national science bodies – have been working on the governance and ethics of germline editing.

This latest nuts-and-bolts draft of a regulatory framework for allowing CRISPR babies comes from the International Commission on the Clinical Use of Human Germline Genome Editing, a working group composed of researchers and clinicians from the U.S. National Academy of Medicine, National Academy of Sciences, and the British counterpart to the national academies, The Royal Society. As of Sept. 29, the document was published in draft form, but not yet peer-reviewed.

"Rapidly advancing technical capabilities in genome editing, and the reported use of heritable human genome editing (HHGE) in 2018 leading to the birth of children whose DNA had been edited, led to renewed global calls for consideration of the scientific, societal, and governance issues associated with this technology," the report states.

A rogue Chinese scientist in 2018 gene-edited twin girls with the aim of adding genes that make them more resistant to HIV, according to previous reporting by MedicineNet. The scientific community was horrified by the experiment, roundly excoriated as sloppy, dangerous and unethical. The gene editing technology Chinese researcher He Jiankui used to illegally edit the embryos is not yet safe for germline editing.

He is serving a three-year prison sentence in China for illegal medical practice in connection with the experiment, according to Scientific American.

How Does CRISPR Work?

Scientists for decades have been editing genes using various technologies, some more accurate and efficient than others, but all of which require lots of labor for relatively uncertain results, according to the NIH Genetics Home Reference.

"The CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods," the NIH states. "CRISPR-Cas9 was adapted from a naturally occurring genome editing system in bacteria. The bacteria capture snippets of DNA from invading viruses and use them to create DNA segments known as CRISPR arrays."

"The CRISPR arrays allow the bacteria to 'remember' the viruses (or closely related ones)," the NIH states. "If the viruses attack again, the bacteria produce RNA segments from the CRISPR arrays to target the viruses' DNA. The bacteria then use Cas9 or a similar enzyme to cut the DNA apart, which disables the virus."

Scientists use this CRISPR enzyme to "snip" out pieces of unwanted DNA and replace them with a segment edited to be healthy. This could theoretically cure deadly genetic disorders like Tay Sachs that leads to infant death or sickle cell anemia which is also a big cause of death and disability, among many others.

Not only would each CRISPR baby be free of these conditions, every subsequent generation in the baby's family would also be free of these disorders.

But the power of germline editing works both ways, as the international commission pointed out; an error could blight an entire family line into the indefinite future. That's why bioethicists, researchers and clinicians alike were horrified by He's announcement he had edited baby twin girls.

What Should You Do if Genetic Disease Runs in Your Family?

If you are susceptible to an inherited disease or if you have a genetic condition in your family and you want to have children, your current options include genetic counseling.

Genetics professionals are healthcare professionals with specialized degrees and experience in medical genetics and counseling. Genetics professionals include geneticists, genetic counselors and genetics nurses, according to the National Human Genome Research Institute (NHGRI).

Your health care provider may refer you to a geneticist - a medical doctor or medical researcher - who specializes in your disease or disorder. A medical geneticist has completed a fellowship or has other advanced training in medical genetics. While a genetic counselor or genetic nurse may help you with testing decisions and support issues, a medical geneticist will make the actual diagnosis of a disease or condition. Many genetic diseases are so rare that only a geneticist can provide the most complete and current information about your condition, according to the NHGRI.

Along with a medical geneticist, you may also be referred to a physician who is a specialist in the type of disorder you have. For example, if a genetic test is positive for colon cancer, you might be referred to an oncologist. For a diagnosis of Huntington disease, you may be referred to a neurologist, according to the NHGRI.

Genetic professionals work as members of health care teams providing information and support to individuals or families who have genetic disorders or may be at risk for inherited conditions. According to the NHGRI, genetic professionals may perform the following services:

  • Assess the risk of a genetic disorder by researching a family's history and evaluating medical records.
  • Weigh the medical, social and ethical decisions surrounding genetic testing.
  • Provide support and information to help a person make a decision about testing.
  • Interpret the results of genetic tests and medical data.
  • Provide counseling or refer individuals and families to support services.
  • Serve as patient advocates.
  • Explain possible treatments or preventive measures.
  • Discuss reproductive options.

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