Read More: Why get a genetic test when the child has already been diagnosed?
Many healthcare providers have difficulty explaining to their patients why a genetic diagnosis is important in addition to a descriptive diagnosis like developmental delay or autism spectrum disorder.
We are looking for more than just a descriptor for what's happening with the child. We want to know why that descriptor is present and why that child has developmental delay or autism.
A diagnosis is just a description, not a cause
It's almost as if a patient is asking, what's wrong with my car? Your car is broken down. That's not a detailed enough answer. A mechanic is not going to know how to fix a broken down car. They need to do a diagnosis on that car. Is the tank out of gas? Are the tires not working? Do we need a new engine?
There can be a variety of reasons why something is not working properly and until we know that specific reason, we don't know how to fix that car or in this case treat that patient. That's one analogy that has helped families understand the importance of having a specific, genetic ideology to their child's developmental delay or autism spectrum disorder.
A real-life example
There may be two children similar in age who both have low muscle tone, speech and language difficulties and developmental delay. If we performed CMA for both of those children, it would not be uncommon to find that one of those children has DiGeorge syndrome, which is also known 22q11.2 deletion syndrome.
It would also not be uncommon for a child with those descriptors to have a deletion that causes Angelman syndrome. These are both conditions that are diagnosed by the CMA but have vastly different prognosis and medical comorbidities for the child.
Very different prognoses
In the case of 22q deletion syndrome, that child should be screened for certain heart defects. Their palate may have abnormalities that are causing the speech and language issues and that individual as well as his or her parents could beat risk for certain psychiatric illnesses if they have the deletion1.
Angelman syndrome carries a high risk for seizures
In contrast, the individual with Angelman syndrome has a very high risk for seizures. And that child could benefit from an evaluation with a neurologist to get a baseline understanding of what's happening with the brain. And Angelman syndrome is most often de novo in a patient. De novo means that the deletion is new in the patient and is not carried by one of the parents.
So two children can present in very similar ways. Both can have a general diagnosis of delay or autism. But both can have very different conditions. And those children need to be treated differently. The families can also find out the facts about their child's genetic syndrome and find unique support with that genetic community.
It helps to know specifically what the problem is
There are support groups for both of these conditions and it benefits parents and other family members to have an understanding of what is happening with their child. Parents might be harboring some blame and genetic testing can really begin to help families cope with some of these issues.
1. McDonald-McGinn DM, Emanuel BS, Zackai EH. 22q11.2 Deletion Syndrome. 1999 Sep 23 [Updated 2013 Feb 28]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2015. Available from:http://www.ncbi.nlm.nih.gov/books/NBK1523/
2. Dagli AI, Mueller J, Williams CA. Angelman Syndrome. 1998 Sep 15 [Updated 2015 May 14]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2015.Available from: http://www.ncbi.nlm.nih.gov/books/NBK1144/