This document discusses current theories on the etiology (causes) of autism spectrum disorder (ASD). It notes that ASD is a complex neurological and developmental disorder that affects social interaction, communication, and behavior. While there is no single known cause, factors discussed include genetic factors like mutations and chromosomal abnormalities. Environmental factors like advanced parental age or pregnancy/birth complications may also play a role. Theories are that ASD has both genetic and non-genetic causes. Comorbid conditions commonly associated with ASD are also reviewed. In summary, the exact causes of ASD are still being determined as research on both genetic and environmental factors continues.

1. AUTISM SPECTRUM
DISORDER
(ASD)
ETIOLOGY (CURRENT THEORIES) OF ASD
BY: SHABEER KHAN
AIU 2020

2. CONTENTS
• INTRODUCTION
• CHARACTERISTICS
• ETIOLOGY
• COMORBID DISORDER
• CONCLUSION
• REFERENCES

3. WHAT IS ASD…?

4. • AUTISM SPECTRUM DISORDER IS A COMPLEX
NEUROLOGICAL AND DEVELOPMENTAL DISORDER THAT
EFFECTS HOW PEOPLE INTERACT WITH OTHERS,
COMMUNICATE AND BEHAVE .
• IT SAID TO BE DEVELOPMENTAL DISORDER ,BECAUSE
SYMPTOMS GENERALLY APPEARS IN FIRST 1 TO 3 YEARS
(EARLY)

5. WHY CALLED AUTISM SPECTRUM
DISORDER
• WE USED AUTISM SPECTRUM DISORDER BECAUSE IT IS
IN FACT A SPECTRUM NOT A SINGLE DISORDER
• INDIVIDUAL FALL ON THE SPECTRUM IN DIFFERENT
WAYS HAVING DIFFERENT KINDS OF ABILITIES AND
CHARACTERISTICS
• BUT THEY ALL SHARE CERTAIN THINGS IN COMMON

6. CHARACTERISTICS :

7. THEORIES OF ETIOLOGY :
• WHEN IT COMES TO THE ETIOLOGY OF AUTISM,
VARIOUS THEORIES HAVE BEEN PROPOSED IN THE
LAST FEW DECADES.
• QUESTIONS AROUND WHAT CAUSES AUTISM AND ITS
IMPACT ON MODERN-DAY SOCIETY HAVE BEEN A
SUBJECT OF INTENSE DISCUSSION
• THERE IS NO CLEAR CUT CAUSE OF ASD OR AUTISM
HAS NO SINGLE CAUSE

8. SUPPORTING FACTS ON ETIOLOGY OF AUTISM…
CAUSES

9. GENETIC FACTORS:
• THE ETIOLOGY OF ASD IS LIKELY TO BE
MULTIFACTORIAL, WITH BOTH GENETIC AND NON-
GENETIC FACTORS PLAYING A ROLE .
• RESEARCH TELLS US THAT AUTISM TENDS TO RUN IN
FAMILIES. CHANGES IN CERTAIN GENES INCREASE THE
RISK THAT A CHILD WILL DEVELOP AUTISM.(AUTISM
SPEAKS G. RESEARCH)
• ASD IS OFTEN ASSOCIATED WITH CHROMOSOMAL
ABNORMALITIES.

10. AUTISM’S GENETIC RISK FACTORS
BY MUTATION ON X-CHROMOSOME
• SEVERAL DIFFERENT GENES APPEAR TO PLAY A ROLE IN AUTISM
SPECTRUM DISORDER.
• IN SOME CASES, THE AUTISM SPECTRUM DISORDER CAN BE
ASSOCIATED WITH A GENETIC DISORDER CALLED RETT SYNDROME
(AUTISTIC BEHAVIOR IN GIRLS )
• OR
• FRAGILE X SYNDROME (FXS) (IN BOYS 20 %). IN OTHER CASES,
GENETIC MUTATIONS CAN INCREASE THE LIKELIHOOD OF AUTISM.

12. TWIN STUDIES :
• EARLY STUDIES OF
TWINS HAD
ESTIMATED
HERITABILITY TO BE
OVER 90%.
• THE INCIDENCE OF
AUTISM SPECTRUM
DISORDER IN BOTH
IDENTICAL TWINS IS
MUCH HIGHER THAN
IN FRATERNAL
TWINS. IF ONE OF
THE IDENTICAL
TWINS HAS IT, THE
PROBABILITY OF IT

13. IDENTICAL AND FRATERNAL TWINS

14. OTHER GENETIC INFLUENCES
INCREASE RISK FACTORS
• GENETIC SYNDROME ( EX. FRAGILE X SYNDROME)
• DE NOVO (NEWLY OCCURRING)
• SINGLE NUCLEOTIDE VARIANT
• INHIBITORY AND EXCITATORY NEUROTRANSMISSION

15. ENVIRONMENTAL FACTORS;
• INCREASED RISK
• ADVANCED PARENT AGE(EITHER PARENT)
• PREGNANCY AND BIRTH COMPLICATIONS (EX.
EXTREME PREMATURITY [BEFORE 26 WEEKS],
LOW BIRTH WEIGHT, MULTIPLE PREGNANCIES
[TWIN, TRIPLET, ETC.])
• PREGNANCIES SPACED LESS THAN ONE YEAR
APART

16. FROM EARLY TO LATE

17. EPIGENETICS :

18. RECENTLY BUSTED MYTHS ON ETIOLOGY
OF AUTISM/DISCREDITED THEORIES :
• A NEW STUDY HAS FOUND THAT THERE IS NO LINK
BETWEEN AUTISM AND MERCURY LEVELS IN MOTHERS
AND THEIR NEWBORNS.
• GENETICS ALONE CANNOT BE RESPONSIBLE FOR
AUTISM
• VACCINES MAY CAUSE AUTISM – NO THEY DO NOT!
• ENVIRONMENTAL FACTORS LIKE POOR PARENTING OR
“REFRIGERATOR “MUMS (REFUSED)
• THE EXACT CAUSE OF AUTISM IS YET TO BE
DETERMINED.

19. WHAT IS COMORBIDITY..?

20. COMORBIDITY OF ASD:

21. COMORBIDITY OF ASD INCLUDE :
• EPILEPSY/SEIZURES
• SLEEP DISORDERS/DISTURBANCE
• ADHD
• GASTROINTESTINAL DISORDERS
• FEEDING/EATING CHALLENGES
• OBESITY
• ANXIETY
• DEPRESSION
• BIPOLAR DISORDER

22. NOTE:
• THE CURRENT STUDY PROVIDES A REVIEW OF THE
LITERATURE ON COMORBIDITY, IN RELATION TO
COMORBID PSYCHIATRIC AND MEDICAL DISORDERS IN
BABIES AND INFANTS, CHILDREN, ADULTS AND
ACROSS THE LIFESPAN.
• THESE ISSUES CAN LAST THROUGHOUT LIFE, BUT MAY
ALSO APPEAR AT DIFFERENT DEVELOPMENTAL
STAGES.
• MULTIPLE STUDIES SHOW THAT PEOPLE WITH ASD
HAVE SIGNIFICANTLY SHORTER LIFESPANS NOT DUE
TO AUTISM ITSELF, BUT TO ACCOMPANYING MENTAL
AND PHYSICAL HEALTH CONDITIONS.

23. DIAGNOSIS OF COMORBIDITIES CAN BE
CHALLENGING :
• BECAUSE MANY PEOPLE WITH ASD HAVE DIFFICULTY
RECOGNIZING AND COMMUNICATING THEIR
SYMPTOMS. ONE CAN NOT EASILY DIFFERENTIATE
WHETHER THESE BEHAVIORS ARE RELATED TO ASD OR
TO PHYSICAL DISCOMFORT CAUSED BY A CO-
OCCURRING CONDITION.
• THUS COMMODITIES IN THIS CONDITION REQUIRES
MORE RESEARCH

24. REFERENCES :
• AUTISM SPEAKS …HTTPS://WWW.AUTISMSPEAKS.ORG/WHAT-CAUSES-
AUTISM
• ASI A, DEMAYO MM, GLOZIER N, GUASTELLA AJ. AN OVERVIEW OF AUTISM
SPECTRUM DISORDER, HETEROGENEITY AND TREATMENT OPTIONS.
NEUROSCI BULL. 2017;33(2):183–93.
HTTPS://DOI.ORG/10.1007/S12264-017-0100-Y . - DOI - PMC - PUBMED
• VOLKMAR FR, WOLF JM. WHEN CHILDREN WITH AUTISM BECOME ADULTS.
WORLD PSYCHIATRY. 2013;12(1):79–80.
HTTPS://DOI.ORG/10.1002/WPS.20020 . - DOI - PMC - PUBMED

25. THANK YOU
• BE HAPPY……