About half of parents of children with ASD notice their child's unusual behaviors by age 18 months, and about four-fifths notice by age 24 months. According to an article, failure to meet any of the following milestones "is an absolute indication to proceed with further evaluations. Delay in referral for such testing may delay early diagnosis and treatment and affect the long-term outcome". * No response to name (or eye-to-eye gaze) by 6 months. * No babbling by 12 months. * No gesturing (pointing, waving, etc.) by 12 months. * No single words by 16 months. * No two-word (spontaneous, not just echolalic) phrases by 24 months. * Loss of any language or social skills, at any age. The United States Preventive Services Task Force in 2016 found it was unclear if screening was beneficial or harmful among children in whom there is no concern. The Japanese practice is to screen all children for ASD at 18 and 24 months, using<unk> -specific formal screening tests. In contrast, in the UK, children whose families or doctors recognize possible signs of<unk>  are screened. It is not known which approach is more effective. Screening tools include the Modified Checklist for<unk>  in Toddlers (M-CHAT), the Early Screening of<unk> ic Traits Questionnaire, and the First Year Inventory; initial data on M-CHAT and its predecessor, the Checklist for<unk>  in Toddlers (CHAT), on children aged 18–30 months suggests that it is best used in a clinical setting and that it has low sensitivity (many false-negatives) but good specificity (few false-positives). It may be more accurate to precede these tests with a broadband screener that does not distinguish ASD from other developmental disorders. Screening tools designed for one culture's norms for behaviors like eye contact may be inappropriate for a different culture. Although genetic screening for<unk>  is generally still impractical, it can be considered in some cases, such as children with neurological symptoms and dysmorphic features. Some authors suggest that automatic motor assessment could be useful to screen the children with ASD for instance with behavioural motor and emotionals reactions during smartphone watching.
Autism
Schizophrenia
Tourettism
Reactive attachment disorder
Puberphonia
Intellectual disability
Selective mutism
Lesch–Nyhan syndrome