Autism Spectrum Disorder
The most likely diagnosis is autism (Answer A). This child presents with the classic triad of impairments required for autism diagnosis: marked deficits in social relatedness (poor eye contact, refusal to be held), severe communication impairment (language regression from 20 words to nonverbal), and restricted/repetitive behaviors (ritualistic toy lining, hand flapping, insistence on routine). 1
Why Autism is the Correct Diagnosis
This case demonstrates textbook autism with language regression, which is a recognized presentation pattern. The child meets all three DSM-IV-TR diagnostic domains for autistic disorder:
Social Relatedness Impairments
- Poor eye contact is a hallmark feature of autism in preschool children 1
- Refusal to be held indicates marked impairment in social-emotional reciprocity 1
- Lack of interest in social interaction distinguishes autism from other developmental disorders 1
Communication/Play Deficits
- Language regression (speaking 20 words at age 2, then stopping at 2.5 years) is a recognized pattern in autism, though less common than delayed onset 1
- Total lack of verbal communication at age 5 represents severe impairment 1
- Normal hearing test rules out deafness, a common parental concern that mimics autism 1
- The ability to write alphabets demonstrates some cognitive capacity despite absent speech 1
Restricted Interests and Repetitive Behaviors
- Hours spent lining up toys represents adherence to nonfunctional routines 1
- Hand flapping is a classic stereotyped motor mannerism seen in autism 1
- Extreme distress when routine is interrupted indicates marked resistance to change 1
Why Other Diagnoses Are Incorrect
Asperger Syndrome (Answer D) is Excluded
Asperger syndrome requires no clinically significant delay in language development, which this child clearly has. 1 The defining feature of Asperger disorder is relatively preserved language with social deficits, whereas this child has severe language impairment with regression to complete mutism. 1
Attention Deficit Disorder (Answer B) is Excluded
ADHD does not cause language regression, poor eye contact, hand flapping, or ritualistic behaviors. 2 ADHD symptoms must be present before age 12 across multiple settings and involve inattention/hyperactivity, not the social communication deficits and stereotypies seen here. 2
Mental Retardation/Intellectual Disability (Answer C) is Excluded
The ability to write alphabets at age 5 demonstrates cognitive skills inconsistent with global intellectual disability as the primary diagnosis. 1 While autism frequently co-occurs with intellectual disability, the prominent social deficits, stereotypies, and insistence on sameness point to autism as the primary condition. 1, 3 Children with isolated intellectual disability typically maintain social interest and do not show the ritualistic behaviors or sensory peculiarities characteristic of autism. 1
Clinical Significance and Prognosis
Early diagnosis is critical because intervention effectiveness increases with earlier implementation. 1 The absence of communicative speech by age 5 is a negative prognostic indicator for ultimate outcome. 1 This child requires:
- Immediate referral for comprehensive autism evaluation using standardized measures like the Autism Diagnostic Observation Schedule 3
- Intensive behavioral interventions such as Early Start Denver Model, which show small to medium effect sizes for improving language and social communication 3
- Screening for common comorbidities including epilepsy (21% prevalence in autism with intellectual disability), sleep difficulties, anxiety, and depression 3
Common pitfall to avoid: Do not delay diagnosis waiting for the child to "grow out of it" or attributing symptoms solely to hearing problems when audiometry is normal. 1 Parents commonly express concern that their child might be deaf due to inconsistent responsiveness, but normal hearing with poor social communication points directly to autism. 1