The sibling study conducted in this paper examined 664 infants between 18 and 36 months who had an older biological sibling with diagnosed autism spectrum disorder (ASD). Published earlier this month, the study found that nearly 19% of the infants developed ASD, with a three fold increase in risk for males. While previous studies had shown an increase in risk, the risk was estimated to be only 3-10%. Given the large scale of trial, the data accounted for many potential biases which may have influenced findings in previous studies. This insight emphasises the need for screening and close observation from birth, particularly in boys, as early identification and thus early intervention is currently considered the best method in improving the symptoms and reducing effects of ASD.

Full article: http://pediatrics.aappublications.org/content/early/2011/08/11/peds.2010-2825.full.pdf+html
Summary: http://pediatrics.aappublications.org/content/early/2011/08/11/peds.2010-2825
PMID: 21844053

Title: Recurrence Risk for Autism Spectrum Disorders: A Baby Siblings Research Consortium Study
Authors: Ozonoff S, Young G S, Carter A, Messinger D, Yimiya N, Zwaigenbaum L et al
Journal Title: Pediatrics