What are the diagnostic criteria for Autism Spectrum Disorder (ASD) in a 3-year-old female?

Diagnostic Criteria for Autism Spectrum Disorder in a 3-Year-Old Female

The diagnosis of ASD in a 3-year-old female requires persistent deficits in social communication and social interaction across multiple contexts, plus at least two types of restricted, repetitive patterns of behavior, with symptoms present in early development causing clinically significant impairment. 1

Core Domain 1: Social Communication and Social Interaction Deficits

All three of the following must be present across multiple contexts 1:

• Deficits in social-emotional reciprocity: Reduced sharing of emotions and interests, failure to initiate or respond to social interactions, abnormal back-and-forth conversation 1, 2

• Deficits in nonverbal communicative behaviors: Poor integration of verbal and nonverbal communication, abnormalities in eye contact and body language, deficits in understanding and use of gestures, complete lack of facial expressions and nonverbal communication 1

• Deficits in developing, maintaining, and understanding relationships: Difficulties adjusting behavior to suit various social contexts, difficulties in sharing imaginative play or making friends, absence of interest in peers 1

Core Domain 2: Restricted, Repetitive Patterns of Behavior

At least two of the following four must be present 1:

• Stereotyped or repetitive motor movements, use of objects, or speech: Motor stereotypies, lining up toys, echolalia, idiosyncratic phrases 1

• Insistence on sameness, inflexible adherence to routines, or ritualized patterns: Extreme distress at small changes, difficulties with transitions, rigid thinking patterns, ritualized patterns of verbal or nonverbal behavior 1

• Highly restricted, fixated interests: Abnormal in intensity or focus, strong attachment to or preoccupation with unusual objects 1

• Hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of environment: Apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement 1

Additional Required Criteria

Timing and developmental presentation 1:

• Symptoms must be present in the early developmental period (typically recognizable by age 2-3 years) 1
• At age 3, symptoms should be fully manifest, though some may have been masked by learned strategies 1
• Diagnostic stability is well established in children aged 24 months and older 1

Functional impairment 1:

• Symptoms must cause clinically significant impairment in social, occupational, or other important areas of current functioning 1

Exclusion criteria 1:

• Disturbances are not better explained by intellectual disability or global developmental delay (though ASD and intellectual disability frequently co-occur) 1

Severity Specification

Specify current severity level separately for social communication and restricted/repetitive behaviors based on support required 1:

• Level 3 "Requiring very substantial support": Severe deficits causing severe impairments in functioning 1
• Level 2 "Requiring substantial support": Marked deficits, impairments obvious even with supports in place 1
• Level 1 "Requiring support": Without supports, deficits cause noticeable impairments 1

Comprehensive Diagnostic Assessment Components

Direct observation using standardized measures 3, 1:

• Autism Diagnostic Observation Schedule (ADOS) - sensitivity 91%, specificity 76% 2
• Direct observation of social interaction patterns and restricted/repetitive behaviors 3

Structured parent interview 3, 1:

• Autism Diagnostic Interview-Revised (ADI-R) - sensitivity 80%, specificity 72% 2
• Detailed developmental history including timing of symptom onset 3

Cognitive and language assessment 3, 1:

• Formal cognitive testing to assess intellectual functioning 3
• Language evaluation to differentiate from primary language disorders 4

Medical evaluation 3:

• Formal audiogram to rule out hearing loss 3
• Physical examination including Wood's lamp examination for tuberous sclerosis 5

Genetic Testing Recommendations

First-tier genetic evaluation 3:

• Chromosomal microarray (CMA) 3, 5
• Fragile X DNA testing 3, 5
• MECP2 gene testing in females 3, 5

Clinical genetics consultation 5:

• Thorough clinical genetics evaluation identifies underlying etiology in 30-40% of individuals 5
• Genetic counseling should be provided to all families with recurrence risk information 3

Common Pitfalls to Avoid

• Do not delay evaluation based on "wait and see" approach, as early identification enables timely intervention with significantly improved outcomes 5
• Do not focus only on core ASD symptoms - screen for common comorbidities including sleep difficulties (13%), anxiety (11%), depression (20%), and epilepsy (21% with co-occurring intellectual disability) 2
• Do not fail to assess adaptive functioning across all domains, as this impacts severity specification and treatment planning 3