Eric Morrow, MD, PhD, director of the Developmental Disorders Genetics Research Program (DDGRP), was part of an international collaboration that included Harvard Medical School and an international team of clinicians and families from the United States, Turkey, Pakistan and the Middle East. The researchers collaborated on and recently completed a research project involving the application of novel genome-wide DNA sequencing methods, known as whole-exome sequencing (WES), to make new genetic diagnoses. WES allows geneticists to investigate the coding portions of every gene in the human genome.
The study found that WES provides a high degree of utility in discovering the genetic cause for autism in a large group of families for whom there were no previously known genetic causes. Many of these genetic causes were due to mild genetic changes in genes that would normally cause more severe neurologic conditions. For example, genetic changes were found in a number of genes that would typically cause severe metabolic disorders. However, since the genetic changes were somewhat mild in these genes, they resulted in an atypical presentation that mimics the broad and heterogeneous symptoms of autism instead of the typical syndrome. The researchers also discovered several new genes that had not been previously implicated in autism, such as the gene Syne1, which is thought to be involved in the process by which experience shapes synapses during learning.
Modern genetic tests are an important part of state-of-the-art methods for making an autism diagnosis. New genetic methods such as WES provide unprecedented opportunities to make genetic diagnoses that explain the medical cause of autism in a subset of patients. These diagnoses may be critical to explaining to families why their children have development delays and to predicting risk of recurrence, outcome and response to treatments.
An article entitled “Inherited Causes of Autism” presents the study findings in the January, 2013 issue of Neuron, a high-impact journal in the neuroscience field.