This month, we pore over null results from a study of the accuracy of emotion recognition skills in autistic people, clinical trials of a vasopressin drug called balovaptan, and an analysis of ‘systemizing’ abilities in autistic children.

People with autism have more mutations than others do in both mitochondrial DNA and nuclear DNA that affects mitochondrial function.

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.

Mice that lack a segment of chromosome 22 — a mutation associated with autism — have unusually sparse connections between brain regions.

Variants of some mitochondrial genes may contribute to autism — in some cases, by teaming up with genes in the nucleus.

The combination of obesity and diabetes in a pregnant woman substantially increases the likelihood that her child will have autism.

Telomeres, the structures at the tips of chromosomes, tend to be unusually short in people with autism and their immediate family members.

Children born to women who develop diabetes during the first or second trimester of pregnancy increase their risk of autism by 42 percent.

A single gene mutation leads to Rett syndrome, but other variants may modify the severity of an individual’s symptoms, according to a study published 28 February in PLoS One.

A handful of studies point to dietary deficiencies as a contributing factor in some forms of autism, suggesting that supplements — such as carnitine or certain amino acids — may help treat and even prevent the disorder.