Year : 2020 | Volume
: 9 | Issue : 4 | Page : 121-
Search for cause of autism spectrum disorder
Asok Kumar Datta
Department of Pediatrics, Burdwan Medical College, Burdwan, West Bengal, India
Asok Kumar Datta
Department of Pediatrics, Burdwan Medical College, Burdwan, West Bengal
|How to cite this article:|
Datta AK. Search for cause of autism spectrum disorder.J Pediatr Assoc India 2020;9:121-121
|How to cite this URL:|
Datta AK. Search for cause of autism spectrum disorder. J Pediatr Assoc India [serial online] 2020 [cited 2022 Nov 27 ];9:121-121
Available from: http://www.jpai.in//text.asp?2020/9/4/121/333371
Incidence of autism spectrum disorder (ASD) is rapidly rising. The awareness among parents and practicing pediatricians is also increasing, resulting in early detection and initiation of interaction intervention. Still, there is confusion related to age of final labeling of the disease, which is now 3 years. Confusion also exists on its cause.
Recently, researchers detected some important clues as the cause of this mysterious condition. Failure to detect ASD-specific biological motion in these cases is an important issue. Motion detection in humans is controlled mainly at two centers in the brain. One is for general motion of nonspecific in nature, at the medial temporal sulcus. The other type of movement is called biological motion, controlled from the center is lying on superior temporal sulcus (STS). Such biological motion detection fails to function properly in ASD. As a result, when someone is coming toward them or talking to them, they usually fail to interpret it, and eye contact is not properly formed. Face recognition is defective, and instead of looking toward face, the subjects usually look to the lower part of the face like mouth.
The concept of malfunctioning social brain is also established in ASD. The social brain is said to be concerned with the function of social interaction, empathy, maintaining relations, and social adaptation. The regions involved are inferior temporal cortex for face recognition, amygdala for emotion, STS for biological motion, mirror neuron system for empathy, area of temporoparietal junction involved in theory of mind, and hypothalamus for overall aspects. Stephen Gotts et al. at the National Institute of Mental Health used functional brain imaging to find that such neural circuit is disorganized in ASD.
The gene function and environmental interaction are the key areas for disturbance. There are usually two types of disturbances – one is the copy number variations (CNVs) and the other is the single-nucleotide polymorphism (SNP). The chromosome number 7 alteration due to CNV is implicated as one cause of ASD. CNV may be deletions, duplication, and other disorders, where a small portion of gene (30–40) is altered, seen in ASD. The reverse of this is deletion of the same part of chromosome number 7, which gives rise to William's syndrome. Here, the child is very much social but sufferers from multiple congenital anomalies. It is clear now that ASD is due to involvement of multiple genes, though SNP may also rarely give rise to ASD. Genetic expression is also dependent on environment. It is found that face recognition is disturbed in children who are exposed to mobile or television for long time from early infancy. These children are fond of objects rather than human face.
The treatment is to enhance the interaction. Therefore, parents should be taught how to interact with other people and children of similar age. The brain-derived neurotropic factor (BDNF) is less released in this disorder. BDNF is concerned with the release of neurotransmitters from presynaptic vesicle. The resulting defect leads to poor synaptic functions. Recently, there are certain drugs that have been introduced which increase the level of such BDNF in synapse. This claim requires more studies. Until now, parenteral interaction for more than 40 h in a week is considered the first choice in management.
The author acknowledges Dr. Eric R. Kandel's Citation for the Nobel Prize in Physiology or Medicine – The Disordered Mind – What Unusual Brains Tell Us about Ourselves – Paperback edition published by Robinson in 2021.