Here is a link to an article on the high rate of autism amongst Somalis in Minnesota. Key quote; "Out of 100 children in the Minneapolis Schools early childhood special education classroom program for autism, 25 percent of them are Somali. The district as a whole has only about 6 percent of students who speak or hear Somali language at home. " This is especially interesting because the same thing has been reported in Sweden. Also of note, these are the more severely, less well functioning types of autistic children, making it less likely this is a difference in diagnostic criteria.
The cause for the increase in autism diagnosis remains a mystery. In this article, vaccination is again blamed. There remains no credible science supporting this contention. Thimerasol has long been removed from vaccines, so it is difficult to blame vaccines as a cause for the Somalis. Also, other groups migrating into the U.S. should be showing the same increase if vaccines were causative. We have been vaccinating for a long time. This increase in autism we are seeing is relatively recent. The timing has never made sense to me.
There is evidence of genetic linkage for autism in the literature. Reports like these are important as they may serve as additional clues. As a result of this population, some have speculated on the influence of female testosterone and Vitamin D levels. Studies looking at seasonal incidence of autism and date of birth may be important. Most importantly, we need a true baseline for the incidence of autism in Somalia. We already have some clues there, as none of the children in Minnesota with autism were born in Somalia.
Some combination of genetics, environmental and behavioral factors remains our best bet here IMHO.