The ‘Perfect’ Baby?

The concept of designer babies refers to babies that have been given special traits through genetic engineering and modification. This could be done either by altering the genes of the egg, the sperm or via other techniques like PGT that deal with embryo selection largely.

In simple terms, gene-editing is the process of making certain changes to the genetic code or DNA. Dating back to 2018, a Chinese researcher named He Jiankui made startling revelations when he revealed that he had used CRISPR to make the world’s first genetically-edited babies! The couple who underwent the procedure subsequently gave birth to twins — Lulu and Nana! So, how does one go about with editing cells and selecting embryos?

Editing Cells

Genetic editing in humans could be perceived as being controversial. However, in recent years a plethora of genetic technologies have advanced and developed rapidly. With newer reproductive genetic technologies showing up, from non-invasive prenatal diagnosis (NIPD) to preimplantation genetic testing aka PGT (this differing from gene editing).

Dr Harsh Sethi, Head of Advanced Genomic Technologies Division, FRIGE Institute of Human Genetics, Ahmedabad sheds light here, “The PGT-M technology first screens the parents’ DNA to identify certain ‘landmarks’ that allows to distinguish the DNA from the mother and father.”

These landmarks usually are linked to genetic mutations. On being tested, these landmarks not only allow doctors to know whether a particular DNA carries a genetic mutation but also give information about its very source.

Dr Shruti Bajaj, Director and Consultant Clinical Geneticist, at The Purple Gene Clinic from Mumbai explains that PGT is popularly used in IVF centres across the country and the world today, to select embryos without specific genetic errors. However, she emphasizes that there is a fine line of difference between gene editing and PGT. She adds, “Gene editing deals more with modifying a target DNA molecule by either adding, removing or altering genetic material at specific locations”. Adding, “On the contrary, PGT or commonly known as ‘embryo selection’ does not involve the editing of the embryos but simply its testing being done”. The embryos then without traces of any pre-existing diseases are used.

Elaborating on the same, Dr Harsh Sethi says, “What differentiates gene editing from embryo selection is that it is usually meant to treat or cure any genetic disease by altering or supplementing the DNA sequence in a cell.”

Spotting Mechanism

While PGT and Gene editing are often wrongly synonymously used, the two, certainly serve different purposes. PGT-M typically involves spotting specific diseases which are usually due to ‘single-gene’ errors. In other words, one must know the precise disease they’re looking for if one wants to opt for PGT-M!

Dr Shruti quips, “We cannot blindly simply order a PGT-M for non-specific diseases”. She explains that PGT, too, comes with two variations. The one that is tweaked to test for specific monogenic diseases usually are called PGT-M while when the same PGT test is used to check for ‘numerical genetic aberrations’ in embryos, this is termed as PGT-A.

Dr Harsh shares that both techniques of PGT and gene editing usually offer high accuracy rates. He adds, “In rare instances, these could either fail to accurately edit the DNA or screen enough for the given DNA mutation”

Admitting that perhaps research in technology development is something that is still in process, he shares that gene therapy is gaining prominence in being able to treat several rare disorders, including Duchenne muscular dystrophy and spinal muscular dystrophy. Something that is now even available in India.

Pros & Cons

Newer reproductive techniques such as gene-editing or PGT and its types could seem promising, however they come with their own pros and cons. One of the biggest benefits for couples who choose PGT-M is the ability to screen and implant embryos that don’t carry any genetic defect!

“This allows couples to ensure that their children won’t be affected by any genetic disorder,” says Dr Harsh. Cautioning as well, “The technology here is prohibitively expensive as it usually requires highly sophisticated laboratory setups, skilled manpower and ultra-clean environment to perform the tests.”

Given the exorbitant rates for the technology deployed, it is a known fact that many couples are simply unable to afford a PGT-M. Further, the cost for these tests would also vary depending on that particular tier of the city.

Dr Shruti says, “It also depends on the disease being looked for along with the complexity of its genetic architecture and the number of embryos to be screened or tested”. These treatments usually could be expected to be anywhere around 2-2.5 lakh onwards, with this just being the start!

Another con of the technique includes the many misconceptions surrounding it, especially in terms of possible failure. Dr Harsh says here, “The technology could make an error; hence it is critical that after embryo selection — when pregnancy is at 16 weeks of gestation, the foetus should be tested for the presence of possible mutations from cells present in the amniotic fluid.”

Babies Ahead

While science seems to have taken a leap in terms of designing and modifying flaws with gene compositions, it is true that a large segment of the Indian population still prefers the ‘natural’ way out!

Couples who find difficulties in conceiving could also look at various other reproductive options, such as using donor sperm or donor oocytes or simply considering adoption. Couples wanting to experience parenthood might be right in switching to such options to avoid the birth of an ‘affected’ child. However, it's best that in most cases we leave such things for nature to decide on!