Two genes have been associated with autistic spectrum disorders (ASD自闭症) in a new study of 661 families. Researchers writing in BioMed Central's newly launched journal Molecular Autism found that variations in the genes for two brain proteins, LRRN3 and LRRTM3, were significantly associated with susceptibility（感情，敏感性） to ASD. Anthony Monaco from the Wellcome Trust Centre for Human Genetics, University of Oxford, UK, worked with an international team of researchers to study four candidate genes in families from the UK, the Netherlands, Italy and Germany. He said, "To our knowledge, this is one of the most comprehensive genetic analyses of association between these important genes in brain connections and ASD risk". The proteins encoded by these two genes have been implicated in brain development, which is often impaired in autistic（孤僻的） individuals. In particular, LRRN3 is thought to play a role in the development and maintenance（维修，保养） of the nervous system, while LRRTM3 is part of a family of proteins thought to organize synaptic（突触的，联合的） connections.

According to Monaco, " A focused candidate gene study was carried out using association approaches to identify common variants in the UK cohort（支持者，同辈） and in additional European populations. This study covered four brain-enriched leucine（白氨酸，亮氨酸）-rich repeat candidates and taken together, there is converging（会聚的，趋同的） evidence that common genetic variants in LRRTM3 and LRRN3 confer susceptibility to ASD. Future studies of these genes and their function will provide valuable insights into their role in ASD pathogenesis（发病机理） ".