Children who lack elasticity of DNA chromosome tend to show worsening social and motor skills beginning at the age of eight, as per a recent study. However, those with 16p11.2 do not showcase this decline.
The duplication and deletion of 16p11.2 often leads to a distinct developmental curve. One percent of autistic individuals are diagnosed with these rare mutations.
The results have been gradually obtained by following 56 youngsters with mutations over a period of several years.
“This helps us understand what these kids look like over time,” says lead investigator Raphael Bernier, associate professor of psychiatry and behavioral sciences at the University of Washington in Seattle. “So many of our studies about the genetics of autism are looking at a single time point; if we don’t consider the developmental change in behaviors, then it can be a little confusing.”
Duplications or deletions in 16p11.2 are not so common; it is seen in an average of 3 out of every 10,000 people. It should be noted that deletions cause individuals to form an enlarged head and make them prone to obesity. These mutations also have an association with intellectual disability, autism, and language problems.
Alternatively, the findings also highlight features that clinicians must observe in order to detect early signs in the life of an individual. Treatments are more effective when the individual is diagnosed at an early stage.
“If we know what’s likely to happen, we can be monitoring those things closely,” says Cheryl Klaiman, assistant professor of pediatrics at Emory University in Atlanta, Georgia, who was not involved in the study.
The team led by Bernier followed 23 youngsters with a history of 16p11.2 chromosome duplication and 33 youngsters with a history of duplication. The team conducted an intensive tracking of the children from the age of 6 months and continued observation until they turned 8 years old. Five children with duplication and eight children with deletion were observed to be diagnosed with autism.
Additionally, the researchers did a thorough assessment of each child at least 3 times over the course of the study. The team conducted standardized tests that were aimed to measure the nonverbal and verbal IQs of the children. They also interviewed parents to assess the child’s behavior in connection with anxiety and other noticeable behaviors like hyperactivity. Motor abilities and social skills such as communication and other day-to-day activities were also measured using adaptive functioning techniques.
The group was comprised of children in the age bracket of 2 to 7 years of age. No noticeable differences were seen at any age in IQ scores, although it was noticed that the group’s profile changed over a period of time. The group with chromosome deletion history showed a decline in social and motor skills, while on the other hand, children with duplication history remained relatively stable.
Both the groups showed an increase in verbal IQ quotient, as is expected with age. However, their nonverbal and behavioral IQs tend to remain relatively stable.