Advancing Research on Intellectual and Developmental Disabilities

A father and son, who has Down Syndrome and is wearing glasses, are playing together in an outdoor playground. Both are smiling.

Improving the health of people with intellectual and developmental disabilities (IDDs) has been central to NICHD’s mission since it was established in 1962. The institute continues to lead research on IDDs six decades later.

One team of NICHD-supported researchers validated a method to identify patients eligible for genetic testing for a rare disorder caused by mutations in the PTEN gene. People with the syndrome, called PTEN hamartoma tumor syndrome (PHTS), have a wide range of symptoms that can include intellectual disability, autism spectrum disorder (ASD), macrocephaly (larger head size), and a higher risk for various cancers. Patients are often undiagnosed and therefore do not benefit from early cancer screenings. The study team developed a computational method to identify people who may benefit from PHTS screening by using hospital diagnostic codes (e.g., ICD-9, ICD-10) to identify predictive symptoms. The approach may be similarly effective at other institutions across the country and can be adapted for other rare genetic disorders.

Another group of investigators evaluated patterns of adaptive skills in children with Down syndrome. Adaptive skills are the conceptual, social, and practical things people learn and use in their daily lives. In most people with Down syndrome, development of adaptive skills is delayed, which can limit their ability to live independently as they grow older. The study team sought to better characterize the nature of adaptive skills in young children with Down syndrome—at the group and individual level—to better understand how to support the development of these skills over time. The team found that the children scored highest in socialization skills, while communication skills were the lowest. They also observed that motor skills could serve as a reliable predictor of adaptive skill development. The findings provide insight into potential intervention opportunities which, in turn, may promote independence for children with Down syndrome.

ASD affects how a person behaves, interacts with others, communicates, and learns. One team of NICHD-funded researchers found that the amygdala—a brain structure that is enlarged in two-year-old children diagnosed with ASD—begins its accelerated growth between 6 and 12 months of age. The amygdala is involved in processing emotions, such as interpreting facial expressions or feeling afraid when exposed to a threat. The findings indicate that therapies to reduce the symptoms of ASD might have the greatest chance of success if they begin in the first year of life, before the amygdala begins its rapid growth.

Another NICHD-supported study reported that changes in the brain’s visual areas during infancy may precede autism diagnosis. The team found that infants who were diagnosed with ASD at 24 months had differences in the visual processing areas of the brain that were already apparent at 6 months of age. The researchers theorized that the disruption in visual processing could interfere with how infants see the world around them, changing how they interact with and learn from caregivers and their environment. These early changes could affect further brain development and play a role in ASD symptoms.

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