People with 1q21.1 deletion tend to have trouble with making particular sounds or processing certain words (articulation differences or phonological processing).
The average verbal and nonverbal IQs for all deletion carriers were within the typical range (90-110).
Interestingly, the majority of individuals with 1q21.1 deletion did not meet criteria to be diagnosed with autism spectrum disorder.
Frequency of Medical Concern
In order to measure the medical and psychiatric differences in 1q21.1 deletion carriers, families participating in the Simons VIP study worked with researchers by providing medical and family history information. Participants with the 1q21.1 deletion, and their non-carrier family members, completed assessments that included specific tests for IQ, memory, behavior, motor skills, and neurological function. Participants were also evaluated for any psychiatric concerns or features of autism.