Researchers at The University of Texas Health Science Center at Houston and the University of the West Indies have joined forces to launch a study of Jamaican children that they hope will unlock the secrets of how genetics and environment may interact to cause autism spectrum disorders.
The research, funded with a two-year, $300,000 exploratory grant from the National Institute of Child Health and Human Development (NICHD) and Fogarty International Center, will train Jamaican health professionals in the most current autism diagnostics; identify an initial sample of Jamaican children ages 3 to 8 who have an autism spectrum disorder; and test the children for specific genes that may interact with exposure to toxins that could affect their neurodevelopment.
"This study will help us identify if autism is related to gene-environment interaction," said Mohammad Hossein Rahbar, Ph.D., principal investigator and professor of epidemiology and biostatistics at The University of Texas School of Public Health. "Jamaica has a stable population, which can help us get a better estimate of the prevalence of autism spectrum disorders linked to environmental causes. In addition, over 90 percent of the population is of African descent, which means less variation in genetics."
Autism spectrum disorders (ASD) are complex, neurodevelopmental and behavioral disorders characterized by impairments in social interaction and communication and repetitive, sometimes obsessive, behaviors. According to the NICHD, a conservative estimate is that one in every 1,000 children has an autism disorder. The national group Autism Speaks puts the number at 1 in 150.
The study will enroll 150 children with autistic disorders from the existing Jamaican ASD database established by Maureen Samms-Vaughan, M.D., Ph.D., principal investigator of the University of the West Indies subcontract. Another group of 150 age- and sex-matched children will be enrolled in this study to serve as a control group and will be compared with children diagnosed with ASD.
"By utilizing the most current available diagnostic methods in Jamaica, our study in the future will promote the earlier identification of children there who are on the autism spectrum," said Katherine Loveland, Ph.D., co-investigator and professor of psychiatry and behavioral sciences at The University of Texas Medical School at Houston. "Also, because most children in Jamaica who need developmental assessment receive it at the clinic directed by Dr. Samms-Vaughan, we will ultimately have the unique opportunity to reach and to research autism in the majority of children in Jamaica who have an autism spectrum disorder."
Samms-Vaughan, professor of child health, child development and behavior at UWI, Mona Campus, is the only developmental and behavioral pediatrician in Jamaica and one of four in the Caribbean. She founded the Child and Family Clinic for Developmental and Behavioral Disorders of Childhood.
"This grant allows us to utilize the most recent diagnostic methods available for participants in the study," Samms-Vaughan said. "There is a lot of information on autism in developed countries, but more limited information from developing countries. Researching similarities and differences across nations will better inform us of the causes. If we can unearth the causes, we will be well on our way to preventing the disabling condition that autism is."
Eric Boerwinkle, Ph.D., professor and director of the Division of Epidemiology at the UT School of Public Health, will lead the project's study of variations in the glutathione-S-transferase genes in relation to autism, as well as their possible interaction with genes involved in contaminant metabolism and metals involved in developmental toxicity. Those metals include mercury, lead, arsenic and cadmium. The study team will collaborate with geneticist Wayne McLaughlin, Ph.D., from UWI's Caribbean Genetics Lab and Gerald Lalor, Ph.D., from UWI's International Centre for Environment and Nuclear Science. The genetic research is funded in part with an additional grant to Boerwinkle from the National Institute of General Medical Sciences. The grant examines genomic sequence information for predicting health and disease beyond traditional risk factors.
The pilot study will set the ground work for large, population-based studies of ASD in Jamaica and help build the infrastructure there for the two universities to train researchers and conduct joint research, said Rahbar, who is director of the Biostatistics, Epidemiology and Research Design Core of the Center for Clinical and Translational Sciences at the UT Health Science Center at Houston.
Standardized screening leads to earlier autism diagnoses in pediatric care