A 3 year old child presents with developmental delayed in speech. He has difficulty in communication and social interactions. His teachers and parents are worried that he is not making any friends. He is observed to have unusual routines and repetitive activities. What is the likely diagnosis?
First, the core concept here is the diagnosis of neurodevelopmental disorders. The key signs mentioned are speech delay, social interaction issues, and repetitive activities. These are classic red flags for ASD according to DSM-5 criteria.
Now, why is the correct answer ASD? The DSM-5 outlines persistent deficits in social communication and restricted, repetitive patterns of behavior. The child's difficulty in making friends and unusual routines fit these criteria. Early signs in toddlers like lack of joint attention or imaginative play also point to ASD.
Looking at the wrong options: if another option was Down syndrome, that's a genetic disorder with physical features and intellectual disability, but not primarily characterized by the social and behavioral issues described. ADHD might involve hyperactivity and inattention, but not the repetitive behaviors. Language disorders focus on speech without the social interaction deficits. Rett syndrome is a rare genetic disorder affecting girls, leading to loss of motor skills, which isn't mentioned here.
The clinical pearl is to remember that ASD is typically diagnosed in early childhood with those specific social and behavioral markers. Early intervention is crucial for better outcomes. So the correct answer should be the one corresponding to ASD.
**Core Concept**
This question assesses the clinical recognition of **autism spectrum disorder (ASD)** in early childhood. Key diagnostic features include delayed speech, impaired social communication, and stereotyped/repetitive behaviors, as outlined in DSM-5 criteria for neurodevelopmental disorders.
**Why the Correct Answer is Right**
The child’s symptoms—speech delay, poor social interaction, and repetitive routines—align with **DSM-5 criteria for ASD**. Early signs include lack of joint attention (e.g., not pointing to share interests), failure to develop peer relationships, and insistence on sameness. These behaviors are **neurodevelopmental in origin** and typically manifest by age 3.
**Why Each Wrong Option is Incorrect**
**Option A:** *Down syndrome* is associated with intellectual disability, distinct facial features, and hypotonia, but not the core social/behavioral deficits of ASD.
**Option B:** *Attention-deficit/hyperactivity disorder (ADHD)* involves inattention or hyperactivity, not repetitive behaviors or impaired communication.
**Option C:** *Selective mutism* is an anxiety disorder causing speech inhibition in specific settings (e.g., school), but it does not involve social interaction deficits or repetitive routines.
**Clinical Pearl / High-Yield Fact**
**ASD screening should occur at 18–24 months** during routine pediatric visits. Early intervention with behavioral therapy improves outcomes. Remember the **3 C’s**: **Communication, Social interaction, and Repetitive Behaviors** as diagnostic pillars.
**Correct Answer: D. Autism Spectrum Disorder**