Autism Spectrum Disorder: Causes And Symptoms

By Author: Manipal Hospitals
Total Articles: 19
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What is Autism Spectrum Disorder?
Autism spectrum disorder (ASD) is a neurological and developmental disorder that affects communication and behaviour. It is known to cause a triad of impairment in imagination, language and social interaction. ASD has a ‘spectrum’ word in it as there is an array of conditions and symptoms people experience. It includes various conditions that are diagnosed separately such as autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS) and Asperger syndrome.

According to the Centre for Disease Control and Prevention, US (CDC~2016), 1 in 54 individuals are affected by ASD. It is more than 4 times more common among boys than among girls.

Causes and Risk Factors of ASD
The exact cause of ASD is not known. The majority are idiopathic or due to acquired brain injury. Genetic factors play a major part in ASD and 15-40% will have an identifiable genetic cause. It may be caused by several genes acting together with environmental factors, some are secondary –syndromic. Children whose brother or sister have ASD are at a higher risk of also having ...
... ASD.

What are the signs and symptoms seen in Autism?
Presentation of symptoms differs between children with ASD; some are perceived by parents as different during infancy, others present with delayed speech development and a proportion regress and lose skills after the first year of life.

Red Flags

In infancy-absence of the social smile by 3 months, more interested in objects than faces, no response to name, inability to follow pointing hand and struggling to imitate actions, No vocalization by 6 months and babbling by 1year.

Commonly seen signs are:

Restricted and repetitive behaviour

Peculiar mannerisms

Unusual attachments to objects

Stereotypies include hand flapping, finger movements, rocking or twirling

Hyperactivity, delayed motor skills with poor coordination

Social skills deficits- prefer being alone, do not make eye contact

Learning difficulty, around 75% of children will have an intellectual disability

How is Autism Diagnosed?
Diagnosing ASD can be difficult, as there is no direct test. It takes the comprehensive holistic evaluation of an individual to place them in the spectrum. This involves developmental screening and comprehensive diagnostic evaluation.

What are the benefits of Early Diagnosis and Genetic Testing?
The intervention provided before three years of age has a much greater impact than intervention provided after age five. It will help in:

The child’s overall language development

Improvement in cognitive functions

Gains in the initiation of spontaneous communication

Understanding the genetic diagnosis

Helps identify other underlying health conditions.

Helps provide an understanding of recurrence risk and planning for a future pregnancy.

Genetic Associations

Current Autism Databases consist of around 1036 reported genes and 2274 reported Copy number variations (CNVs). It is advised to visit the best genetics hospital in Bangalore for early diagnosis. Some of the common genetic conditions and CNVs associated are:

Fragile-X syndrome

Rett syndrome

Angelman syndrome

Tuberous sclerosis

Phenylketonuria

Common CNVs- 1q21.1dup, 7q11.23 dup, 15q11-q13 dup, 16p11.2 del/dup and 22q11.2 del.

Recommended Genetic screening:

Pedigree analysis and clinical evaluation

Chromosomal microarray and Fragile-X testing as a first-tier investigation

MECP2 gene study for females

Targeted gene testing for a suspected specific syndrome

Metabolic testing if clinical indications are seen

How is Autism Spectrum Disorder treated?
Autism is not a medical condition with treatment or a "cure". However, it can be managed and support can be given to the people who need it. Research shows that early intervention can improve a child’s development. However, there is no single best treatment for ASD. Consult with a top genetics doctor in Bangalore to know more about the treatment procedure.

Recurrence risk in a future pregnancy:

If a Genetic cause is identified then accurate recurrence risk and prenatal diagnosis can be offered for future pregnancy. Otherwise, the risk of recurrence is 3-14%.