Autism Spectrum Disorder: Causes and Symptoms

Posted On May 07, 2020

Dr. Mitesh Shetty

HOD & Consultant - Medical Genetics

Manipal Hospitals - Old Airport Road - Bengaluru

autism disorder treatment in Bangalore

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%. 

Dr Mitesh Shetty

Head of Department & Consultant, Medical Genetics

Manipal Hospitals Bangalore – Old Airport Road