On paper, the promise of “hypoallergenic cats” sounds great.

For the first time, people who love cats but are allergic to the furry little guys would be able to open up their homes to them. More cat lovers and more homes for cats is always a good thing, right?

Maybe not in this case.

The quest to create cats who do not trigger allergies depends on CRISPR gene editing, a method that allows scientists to edit, delete and replace sections of the genome. In this case, Virginia-based biotech company InBio wants to edit the genome of domestic felines to block Fel d 1 (Felis domesticus allergen I), a protein produced in cat saliva and in tiny subdermal exocrine glands, which secrete the protein via the same ducts that allow a cat’s fur to grow out from its skin.

Since cats are fastidious neat freaks and groom themselves constantly, the Fel d 1-carrying saliva is applied to their coats several times a day. When it dries, it contaminates a cat’s living space by flaking off the fur as dander or by shedding.

That’s why people who are allergic to cats can suffer symptoms like sneezing, itching and watery eyes not only from petting them, but also from spending time in homes where cats live.

What does Fel d 1 do, and why do cats need it?

The problem is that no one knows why cats produce Fel d 1 and what purpose it serves. Other proteins, like Fel d 4 found in pheromones and Fel d 2, help cats communicate by scent and prevent certain fluids from leaving the bloodstream, respectively.

Take a look at this quote from Nicole Brackett, a geneticist at InBio: (The emphasis on certain words is ours)

“The gene sequences don’t appear to be that well conserved over the course of evolution, which suggest things about whether or not the gene is essential,” Brackett told BioSpace, a life sciences publication. “An essential gene, one that would be required for survival or viability, generally doesn’t change much over evolution, and we’re seeing change between the exotic and domestic cat that suggests that maybe those sequences are not conserved, and maybe the protein is not essential.”

While we understand scientists have to be circumspect, especially regarding research that breaks new ground, that’s a lot of hedging and a lot of uncertainty. (It’s also not clear if Brackett is comparing domestic feline Fel d 1 levels to wild cats — felis sylvestris and lybica — wild felids in general, or hybrids like Bengals and Savannah cats, which are more commonly called exotics.)

The team members developing the allergen gene edit assume Fel d 1 doesn’t have a critical function because individual domestic cats and other species of felids may produce different quantities of the protein.

But that’s a huge assumption, and it’s also presumptuous to assume we humans would know whether the gene edits have a major impact on felines. After all, we still don’t always know when cats are in pain or the reasons for many of their behaviors, and we don’t know what sort of cascade effect can be triggered by shutting down the production of a protein.

The race to make cats hypoallergenic

Companies see a huge opportunity for profit in the cat allergy alleviation market. Last year, Purina announced to much fanfare the availability of a new kind of cat food the company claimed would drastically reduce allergens after about three weeks of putting kitties on the new grub.

The claims haven’t been independently verified, and most press coverage is either credulous or consists of marketing masquerading as news coverage, like this advertisement from Purina that is presented like a news story in USA Today.

Back when a company called HypoCat announced it had conducted successful trials of a “vaccine” that would “neutralize’ Fel d 1, we spoke with immunologist Kamal Tirumalai, who pointed out that humans making such profound changes to companion animals for the sake of human convenience “passes neither the scientific nor the moral smell test.”

Like others, Tirumalai said she worried about unintended consequences.

“A vaccine given to cats to reduce their allergenicity for humans burdens them unnecessarily when human allergy to cats is primarily a human problem and should have a human solution in the form of reducing people’s cat allergies,” Tirumalai told PITB at the time. “Cats are perfect as they are. Why should they be the ones forced to change in order to be accommodated by a human whose immune system happens to have a problem with one of their proteins? This solution just doesn’t pass the moral smell test.”

HypoCat uses an injection to “induce anti-Fel d 1 antibodies in the cat,” while the CRISPR technique would snip the relevant DNA out entirely.

So far, Brackett and her colleagues have deleted one of two cat cells that produce Fel d 1 in samples in a petri dish, and have not made any changes to live animals. The experiments yielded a “55 percent knockout rate” for the Fel d 1 allergen, Brackett said, “which we were really happy with.”

Designer kittens: Gattaca for cats

If subsequent attempts are successful and the company sees commercial promise in editing feline genes, the process could be used to create “designer kittens” or to alter the genomes of existing cats. Brackett told Smithsonian magazine that the goal is to accomplish the latter.

But if it turns out the edits don’t work for existing cats, or the designer kitten trend becomes a thing, there’s another major moral concern similar to the objections to cat cloning. If people buy designer kittens, they’re not opening their homes to the millions of cats who need them.

Manipulating feline DNA isn’t a novel idea. A decade ago, a research team spliced genes from jellyfish using a different method to create cats who glow in UV light as part of a study into feline immunodeficiency virus (FIV).

Ultimately it comes down to what we’re willing to do for the sake of our own convenience. At a time when declawing has finally been outlawed in two states and dozens of cities, and people are more conscientious than ever with regard to their pets, do we want to risk their health so we don’t have to pop a few Benadryl?