1 in 88 children in the US carry a diagnosis of an autism spectrum disorder (ASD). When the diagnosis is made, families are often left with more questions
than answers – Why did this happen? Could we have done anything to prevent it? What can we do to help our child? Scientists at the Greenwood Genetic
Center (GGC) have been working to make sense of this diagnosis and provide those answers.
“Approximately 20% of autism cases can be pinpointed to a specific genetic cause,” explains Steve Skinner, Director of GGC. “Our clinicians and researchers
are working everyday to help families understand those genetic causes and discover possible mechanisms for the cases we can’t yet explain.”
Conditions such as Fragile X syndrome and Phelan-McDermid syndrome, two genetics disorders that are very familiar to GGC scientists, can explain some cases
of autism. These diagnoses also carry other developmental issues and physical characteristics that make them unique. Fragile X is the most common heritable
cause for intellectual disability and is often a first-line diagnostic test for individuals with ASD. Fragile X syndrome testing is recommended by
the American Academy of Pediatrics and the American College of Medical Genetics for all individuals with ASD. In addition to autistic features, Fragile
X syndrome includes intellectual disability and specific physical characteristics. GGC is currently participating in a multi-center clinical trial
investigating both better diagnostic tests and potential therapies for patients with Fragile X syndrome.
Individuals with Phelan-McDermid syndrome exhibit autistic-like behaviors along with significant developmental delays, speech concerns and other physical
characteristics involving the hands, nails and face. Phelan-McDermid syndrome is named for Katy Phelan, PhD, who was Director of GGC’s Cytogenetics
Laboratory at the time she identified the cause of this disorder. GGC researchers and clinicians have maintained a long-standing interest in elucidating
the features, diagnosis and treatments for this condition, as well as in providing educational and family support for those impacted.
GGC has recently launched a diagnostic panel of 62 genes that are known to cause specific syndromes, including Fragile X and Phelan-McDermid, for which
autism is a feature. The panel provides comprehensive testing of these 62 autism-associated genes simultaneously, rather than the more expensive and
time consuming gene-by-gene approach. GGC was recently mentioned in The Wall Street Journal as one of only three institutions in the US offering such
cutting-edge testing. The Center’s testing is the most comprehensive of the three clinically available panels. “Our new autism panel is performed through
next generation sequencing, a technology that allows us to look for mutations in many genes at once,” explains Julie Jones, Senior Director of GGC’s
Molecular Diagnostic Laboratory. Jones is set to present GGC’s experience with this autism panel at the American Society of Human Genetics meeting
in San Francisco this month. “To date we have completed the autism panel on 51 patients with 39 more in progress. Our results have provided clear answers
for five families with many others showing genetic variations that require further study, but may help point us in the right direction.”
“At its most basic level, this information gives many families an answer and can help predict if siblings or other relatives are also at risk,” explains
Skinner. “On a greater scale it provides researchers with the potential to understand on a molecular basis what has caused the autistic features in
this patient and guide us toward potential therapies or even cures.”
Researchers at GGC, funded by a grant from the National Institutes of Health, are also actively investigating methods to make an ASD diagnosis earlier,
quicker and less expensive through studying how cells use tryptophan, an amino acid, as an energy source. Preliminary findings indicate that individuals
with an ASD do not metabolize tryptophan as efficiently as those without an ASD. This efficiency can be measured through customized cell-based technology
in use in the GGC research lab. This technology was developed in collaboration with Biolog in Heyward, CA. “Using such a test for all at-risk children
could provide an early diagnosis at a time when therapies and interventions are most effective,” explains Skinner.