Autism Spectrum Disorder

Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterised by challenges with social communication and interaction, and restricted or repetitive patterns of behaviour, interests, or activities. ASD is called a “spectrum” because it encompasses a wide range of symptoms, skills, and levels of support needed — from highly independent individuals to those requiring significant daily support.

Prevalence

ASD affects approximately 1 in 54 children in the United States, according to the CDC. In India, estimates suggest approximately 1 in 68 children may be affected, though awareness and diagnosis rates remain lower than in Western countries. ASD is approximately 4 times more common in boys than in girls.

Early Signs of ASD

• Limited eye contact and difficulty reading social cues

• Delayed speech and language development

• Repetitive behaviours (hand-flapping, rocking, lining up objects)

• Strong preference for routines and distress at changes

• Unusual sensory sensitivities (to sounds, textures, lights, or tastes)

• Difficulty understanding others’ feelings or expressing their own

The Genetics of ASD

ASD has a strong genetic component — heritability estimates range from 64–91%. However, ASD is genetically complex, involving hundreds of genes and gene variants rather than a single causative mutation. Key genetic findings include:

• Copy number variants (CNVs) — deletions or duplications of chromosomal segments — are found in approximately 10% of ASD cases

• De novo (new) mutations in genes like SHANK3, NRXN1, and CNTNAP2 are associated with ASD

• Rare inherited variants in synaptic genes play a role in ASD susceptibility

• If one identical twin has ASD, the other has a 60–90% chance of also having ASD

Diagnosis and Support

Early diagnosis and intervention are critical for improving outcomes in ASD. Behavioural therapies, speech therapy, occupational therapy, and educational support can make a significant difference. Genetic counselling can help families understand the genetic basis of ASD, assess recurrence risk, and navigate the diagnostic journey.