Clues that problems with mitochondria contribute to autism have been accumulating for decades. In the past five years, a mutant mouse and a flurry of findings have energized the field.

Doctors often conflate autism and intellectual disability, and no wonder: The biological distinction between them is murky. Scientific progress depends on knowing where the conditions intersect — and part ways.

Here is a roundup of news and research for the week of 27 January.