A flurry of Phelan-McDermid syndrome papers: Four studies published this week advance knowledge about Phelan-McDermid syndrome, also known as 22q13 deletion syndrome. The condition is characterized by intellectual disability, developmental delays, behavioral abnormalities and often autism, with considerable variability. A natural-history analysis of data from two cohorts of people with Phelan-McDermid syndrome described delays in acquiring basic skills and regression or loss of skills. A genetic study found that people with small deletions have less impairment overall than those with large deletions or sequence variants. Zeroing in on sensory neural processing, researchers showed that people with the condition have altered responses to auditory stimuli as measured with electroencephalography, and again, the larger the deletion, the greater the change. Finally, children with Phelan-McDermid syndrome displayed greater severity of intellectual disability than those with tuberous sclerosis complex or PTEN hamartoma tumor syndrome.