Abstract
The prevalence of ASD has changed dramatically recently. Centers for Disease Control and Prevention (CDC) reported that the ASD prevalence among 8 - year- old children was 1.47% (one in 68) in the Autism and Developmental Disabilities Monitoring (ADDM) Network surveillance conducted by CDC within 2010, and the prevalence increased by 120% in a decade. Moreover, the ASD prevalence among children aged 3 - 17 years was 2.24% (one in 45) in the 2014 National Health Interview Survey (NHIS) , which showed significant increase (1.25%) compared to the survey from 2011 to 2013. The methods of epidemiological survey of developmental disorders varies, which can be seen in the ADDM and NHIS, where different sampling strategies are used, including different age groups and using different diagnostic criteria. Therefore, the ASD prevalence reported in those surveys are not directly comparable. In addition, previous biological researches suggested the existent of endophenotype. New research methods combining behavioral assessments in community placements with biological assessments using biomarkers has been established overseas for early detection of ASD. Check- up systems for early detection of ASD, which is based on scientific methodology, is needed in Japan as well. The evaluation of the biological characteristics of ASD accurately and non- invasively is required in the future.
