Dr. Sergiu Pașcă

The farther away the species are,

the less likely it is, of course, that the cells will integrate.

So think about it.

It takes just a couple of weeks for the rat to make the cortex.

It takes us 20 weeks to make most of the cortical cells.

So the human cells are always behind.

The rat is finishing development very quickly.

The humans are trying, but they're keeping their pace.

So the integration between the two species happens at some level, but it's not perfect.

And that's actually not our goal.

Our goal has never really been to have perfect integration.

All we wanted to do is to have a better system where we can capture aspects of disease that we wouldn't be able to see in another way or test therapeutics that we wouldn't be able to test in any other way.

And so that's where this actually comes in handy, and it's been very useful.

So for some of these conditions, you know, it's more straightforward than for others.

You know, as you were saying, some of them are very deterministic.

So if you have like 321 chromosomes, you're going to have Down syndrome.

And that's going to be associated with the very classic presentation, you know.

But for others, it turns out, and I think that's where it's much more complicated than just testing and making a decision, is that what we call in genetics the penetrance of the genetic mutations is variable, meaning that you could have a genetic mutation

that in one patient could cause a very severe presentation or phenotype, and in another would be very mild.

It's not the case for Timothy syndrome, where actually it's quite predictable.