[browardchad]

Crucial to the Walsh team's findings was the collaboration of scientists in Jordan, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, Turkey, and the United Arab Emirates. These researchers enrolled 104 families in the study, including 88 families with marriages among cousins. That was an important factor, as rare or recessive genes occur twice as often in such families.

Does this "inclusion" somehow skew the study?

"When we talked to each other, we realized, gee, a lot of our genes that are involved in autism are also their genes that are involved in learning in the brain," Walsh says. "There is nothing more powerful in science than these kinds of serendipitous collisions between people working in related but somewhat distinct fields."

Gee, I'm mystified: why wouldn't the genes involved be related to "learning in the brain?" 

[neverdem]

Does this "inclusion" somehow skew the study?

I'm not a geneticist, but what makes you ask that? There's so much they don't know about what's going on with genetics, that when you can match traits to the various changes, you finally gain some insight.