Prenatal pruning of neurons with copy number variants; and more

Pruning method: Many neurons in the prenatal brain are rife with copy number variants, most of which are eliminated before birth or shortly thereafter, a new study reports. Investigators conducted whole-genome sequencing in neurons from human postmortem brains from before birth to older than 90 years. On average, 25 percent of prenatal cortical neurons carried copy number variants, but the number of neurons with aberrant genomes dropped more than fourfold after birth. Neurons with high numbers of copy number variants also showed altered expression of synaptic genes, suggesting that these cells failed to form connections—and ended up targeted for removal. 

Autism research spotted this week:

• “Systematic functional interrogation of neurodevelopmental disorder risk variants” bioRxiv
• “Parkinsonism co-occurrence among older autistic adults, adults with intellectual disability, and a control sample of adults in national health care claims data” Autism
  See also: “Large study links autism to Parkinson’s disease”
• “Machine learning-derived subtypes of autism reveal distinct genetic contributions from common and rare variants” medRxiv
  See also: “The spectrum goes multidimensional in search of autism subtypes”
• “Associations between simple and complex executive function skills and adaptive function in a sample of 3-year-olds enriched for variation in autism and ADHD traits” The Journal of Child Psychology and Psychiatry
• “Comparing the phenotypic and genetic differences between autistic regression and autism without regression using the SPARK cohort” medRxiv