Diagnosing Autism Spectrum Disorder (ASD) continues to be a challenge for medical science and for families seeking answers. While advances in genetics bring promise for early identification and a deeper understanding of the condition, the clinical reality is still marked by significant gaps. Tests such as karyotype, microarray and genetic sequencing are frequently requested to investigate individuals with suspected autism, but to what extent do these tests really provide definitive answers?
The Role of Genetic Tests in the Diagnosis of Autism
Autism is a neurodevelopmental condition of multifactorial origin, that is, it can be influenced by both genetic and environmental factors. It is estimated that more than 80% of cases have some genetic contribution, but the precise identification of the responsible mutation is still limited. Currently, genetic tests can be divided into three broad categories when the objective is to investigate ASD:
Karyotype with G-Banding – Used to detect structural alterations in chromosomes, such as deletions and larger duplications. Some conditions associated with autism, such as Angelman Syndrome (chromosome 15) and Fragile X Syndrome, can be detected with this technique. However, most autistic individuals have a normal karyotype, making this test inconclusive.
Microarray (SNP-array) – Considered one of the most relevant tests for the genetic investigation of ASD, it allows the detection of small variations in the number of DNA copies (CNVs). Some of these variations have already been associated with autism, but many still have no defined clinical significance. Even so, approximately 10 to 20% of ASD cases may present alterations identifiable by microarray.
Genetic Sequencing – Currently, this is the most promising approach. Complete exome or genome sequencing can reveal mutations in genes known to be associated with ASD, such as SHANK3, CHD8, SCN2A, among others. Despite this, most individuals diagnosed with autism do not have a single responsible mutation, reinforcing the complexity of the condition.
What to Do When the Test Shows Nothing?
A major misconception in the use of genetic tests for autism is to believe that the absence of a detectable alteration rules out the diagnosis. Often, individuals with ASD undergo genetic tests whose results come back “normal” or indicate only variations considered benign polymorphisms. This can cause frustration for parents and professionals who expect a definitive answer from genetics, but the truth is that we still do not have the technology capable of completely mapping the causes of the disorder.
Furthermore, it is essential to remember that autism is defined by clinical and behavioral criteria, and not only by genetic findings. In other words, the presence or absence of a genetic alteration does not change the way an individual develops or the interventions needed to support them.
Where is Science Headed?
Advances in artificial intelligence, machine learning, and big data analysis can help to better interpret the genetic variants associated with ASD. With a greater volume of data and longitudinal studies, the trend is that new genetic biomarkers will be discovered and that, in the future, genetics will play a more significant role in the diagnosis and treatment of autism.
For now, genetic tests should be used as complementary tools and not as the defining tools for a diagnosis. The focus should remain on detailed clinical assessment and early, evidence-based interventions. Science still has a long way to go to fully unravel the mysteries of autism, but each advance brings us closer to a future where more accurate diagnoses and personalized treatments become a reality.
Conclusion
Genetics is undoubtedly a fundamental piece in the autism puzzle, but it cannot be seen as the only answer. The interpretation of tests must be done carefully, always in conjunction with the patient’s clinical history. For families searching for answers, the path can be frustrating, but science continues to advance. And in the meantime, the most effective approach remains clinical, therapeutic and educational support to provide a better quality of life for people on the autistic spectrum.
