As we know, modern genetic research continues to generate new technology at a staggering pace, bringing us
new possibilities for healing as well as new moral challenges. Recently, with the 2012 debut of CRISPR-Cas9
technology, the engineering (think correction) of faulty human genes in vivo or in vitro has been made much easier. But alongside the specter of healing genetic diseases is another scenario, one that has haunted
biologists since the dawn of the Genomic Agethe evil scientist custom-crafting a human being with test tubes
and petri dishes. Since NCER has a special interest in monitoring technological research on human embryos, we
have assembled this powerpoint presentation as our position on prospective uses of CRISPR-Cas9.
PART ONE: WHAT IS CRISPR-Cas9?
CRISPR Cas9 is a genetic editing technique used to alter or edit (snip and splice) faulty genes in adult body
cells or, as an IVF technique, to genetically edit early animal and, most recently, human embryonic cells with
the end of correcting genetic diseases.
Previously, scientists have made enormous strides in their ability to do things with genes: modifying them, moving them from cell to cell, even animal to animal. Its been
possible, in theory, to treat genetic diseases like sickle cell anemia or beta-thalassemia by removing a patients bone
marrow, repairing the damaged gene, and then returning the repaired cells to the patient.
But that approach has not been successful in clinical praxis. Now, with CRISPR, the cost and the ease for
making the necessary genetic editing is such that its really feasible to tailor therapies to the genetic errors of the
patients own cells and essentially to correct their genetic disease.
The contents of the editing tool injected into the cell--the CRISPR-Cas9 complex--includes:
(1) An RNA guide molecule that is programmed to match the mutated gene of interest; (2) the enzyme, Cas9, attached to the
RNA molecule which cuts both strands of the DNA at the mutation point
so that (3) a DNA moleculethat is a copy of the genetic correction can be inserted.
The CRISPR enzyme (green and red) binds to a stretch of double-stranded DNA (purple and red), preparing
to snip out the faulty part.
Distinguish between the uses of CRISPR-Cas9
Genetically engineering somatic or body cells (SCGE)
Genetically engineering germline cells or early embryos (GLGE)
Genetically engineering spare embryos for research purposes (GESE)
o SCGE: the genetic changes end with the patient, they are not transmitted
to the patients descendants.CRISPR once proven safe and effective for use in SCGE in adult
humans would be therapeutic, would not alter the human genome, would be within acceptable clinical safety and efficacy standards,
and would, therefore, be morally acceptable.
o GLGE: not only affects the embryonic patient but all of his/her descendants.
CRISPR used for GLGE, i.e., in embryonic or germline cells for reasons cited below is morally unacceptable.
o GESE: genetic editing of spare embryos to better understand early human development.
Although the decision to alter a human germline cell or the cells of an early embryo may be valuable
to the embryonic patient, as the altered inheritance is carriedinto new genetic combinations,
uncertain and possibly undesirable consequences may ensue. And these
inheritable genetic changes cannot be erased.Good or bad, they will afflict all subsequent generations
of the edited patient.
GESEthe use of CRISPR-Cas9 to genetically engineer
spare embryosmight lead to increased knowledge
of early human embryonic development,but this research is intrinsically immoral:it constitutes an utilitarian, experimental use of embryonic human life resulting in
the direct destructionof endless numbers of spare human embryos who will be used for this
PART TWO: HOW IS CRISPR-Cas9 USED?
(1) To correct genetic diseases
in adult animal models
The CRISPR injection resulted in the normal Fah gene being expressed in 1/250 liver cells in the treated mice. Because these cells were much healthier than the
cells that still expressed the mutated Fah, they divided and produced more daughter cells. Thus, the percentage of healthy cells in the livers of the treated mice was rapidly increased, up to 33% over 30 days. The treated mice also had
significantly less liver damage than untreated mice.
CRISPR ADULT ANIMAL STUDIES PAVETHE WAY FOR CRISPRS
THERAPEUTIC USE IN HUMAN ADULTS (SCGE).
As the article in Nature BiotechnologyGenome editing with Cas9 in adult mice corrects a
disease mutation and phenotype concluded:
Our study indicates that CRISPR-Cas9-mediated genome editing is possible in
adult animals and has potential for correction of human genetic diseases.
The Huang team injected 86 human embryos and then waited 48 hours, enough time for the CRISPR-
Cas9 system and the molecules that replace the missing DNA to actand for the embryos to grow to about eight cells each. Of the 71 embryos that
survived, 54 were genetically tested. This revealed that just 28 were successfully spliced, and that
only a fraction of those contained the replacement genetic material. If you want to do it in normal embryos, you need to be close to 100%, Huang admitted, Thats shy we stopped. We still think
its too immature.
Whats more, Huangs team also found a surprising number of off-target mutations assumed to be introduced by the CRISPR-Cas9
complex acting on other parts of the genome. This effect is one of the principal safety concerns surrounding germline gene editing
because these unintended mutations could be harmful. The rates of such mutations were much higher than those observed in gene-
editing studies of mouse embryos or human adult cells. And Huang notes that his team likely only detected a subset of the unintended
mutations because their study looked only at a portion of the genome, known as the exome. Huang admitted, If we did the whole genome sequence, we would get many more [off-target
mutations]. Despite the troubling results, Huang and his team insist that the nonviable human embryos allow for a more meaningful
CRISPR model than an animal model or one using adult human cells.
CRISPR GLGE in early human embryos for
therapy paves the way for its
eugenics or non-therapeutic use in human embryos
PART THREE: What are the ethics of GLGE use of
Altering the human genomewhen there is no guarantee
of safety and efficacy.
Paving the way for designer babieswhere parents rights trump all;
childs rights are unequivocally denied(especially childs right to lifeand the right to be conceived
within a marital act of his parents unitive love).
Creating a eugenics culture:destroying basic human equality (ubermensch vs. untermensch);
encouraging research hubris;allowing humans who happen
to hold the medical/political powerto design other
non-consenting human beings.
Key to all discussion and future research is making a clear distinction between genome editing in somatic cells and in germ cells. A
voluntary moratorium in the scientific community could be an effective way to discourage human
germline modification and raise public awareness of the difference between these two techniques.
Legitimate concerns regarding the safety and ethical impacts of germline editing must not
impede the significant progress being made in the clinical development of approaches to potentially
cure serious debilitating diseases.
PART FOUR: PROPOSED NCER POSITION ON CRISPR-Cas9
NCERS POSITION ON THE USES OF CRISPR-Cas9:
Nebraska Coalition for Ethical Research encourages the continued use of CRISPR/Cas-9 in animal research and in adult human cell cultures as a means toward its eventual safe and efficacious use for the correction of disease genes in adult human beings.
NCER agrees with the calls for a self-imposed moratorium and an international meeting on the use of CRISPR/Cas-9 for germline genetic engineering on human embryos or human germ cells.
Regardless of the outcome of these initiatives, NCER strongly supports a permanent ban on the use of CRISPR/Cas-9 for germline genetic engineering because it:
Irresponsibly alters the human genome; Paves the way for designer human beings; Denies the childs right to give consent to an experimental technique; Contributes to a eugenics culture that obliterates the basis for:
o Human equality, autonomy, and freedomo Medicine and research that serves the human person, ando Neighborly love and respect between persons
NCER also opposes the research use of CRISPR-Cas9 to edit genes in spare embryos. Despite its good goalincreased genetic knowledge of early embryonic development, this research constitutes an utilitarian, experimental use of embryonic human beings resulting in their direct destruction.
For further discussion of CRISPR-Cas9, please see NCERs powerpoint presentation.