Read More: Why get a genetic test if my child has already been diagnosed?

This is one of the most common questions that our genetic counselors receive from families. Their child may already have been diagnosed with developmental delay or autism spectrum disorder by their doctor, so it can be confusing as to why another diagnosis is needed.

Developmental delay means that a child is not on the same level as his or her same- aged peers. They may be behind in gross motor milestones like walking, talking, or they might be behind in their level of schoolwork.

"Developmental delay" is just a description, not a cause

If a doctor has given your child a diagnosis of developmental delay, or autism spectrum disorder, that's really a description of symptoms that the doctor sees in your child, but it's not the cause of those symptoms. That description can be very important for a lot of reasons, for instance it can help families access certain services, but it does not tell us why the child has these symptoms or answer the common question that many families have: what is the cause of my child's developmental delay or autism spectrum disorder?

Genetic testing is a new level of detailed information

A genetic test can really add a new level of information if a family's child has a diagnosis of developmental delay or autism spectrum disorder. Parents often say, "My child has developmental delay and I talk with other moms of kids with the same diagnosis and all of us seem to be in different places. Our children have different needs. What works for my child doesn't work for my friend's child, or vice versa." Part of the reason why these children are so different is because they are in fact different from each other. Some of them may have a certain genetic condition while the other children can have a very different genetic condition.

Testing helps find the root cause

It's important to get to the root cause of why the developmental delay is present in the first place. By having a deeper genetic understanding we can really provide both the family and their physician with a roadmap. A genetic diagnois can help answer questions like: What is the prognosis for Angelman syndrome? The answer to that question is very different than for a person diagnosed with a different genetic condition like William's syndrome, but both of these children have a diagnosis of developmental delay.

A genetic diagnosis enables better therapy

If the family knows which one of these genetic conditions their child has, they can learn about the very unique capabilities of their child. They can better understand the strengths, interests, and weaknesses their child may experience. It's very important to pinpoint the cause of someone's developmental delay or autism spectrum disorder to provide them the best personalized therapy and developmental care.

Read More: Genetic testing can guide therapy and treatment

A lot of parents ask whether chromosomal microarray (CMA) testing can help with their child’s therapies. There are many different types of therapy that a child can have and a genetic diagnosis can impact therapies differently. For example, one type of therapy is medical or pharmaceutical drug treatment. There are several examples of a genetic diagnosis impacting drug treatment, but a particular condition that causes a seizure disorder is a great example.

Similar looking conditions can require different medications

The medical community knows that there’s a certain change on chromosome number 15 that when identified, indicates that a child has a very high risk for a certain type of seizure. It just so happens that children with that genetic condition do very well on one type of seizure medication and actually do worse on another kind of seizure medication.

So, if we know a child’s underlying genetic condition, such as a change on chromosome 15, we may actually be able to provide a more effective personalized drug therapy that will improve the seizures.

Read More: The importance of identifying genetic disorders

Many times for a child with developmental delay there is an underlying genetic cause. There can be many different genetic causes and some of them are not currently known by the medical community.

It can be important to figure out if there is a genetic cause because it can affect a child's management. There can also be other benefits for the child and for the family.

Co-morbidity

For example, some genetic disorders affect more than just development. The disorder could affect other parts of the body like the heart or the kidneys. These are medical risks that we generally wouldn't anticipate.

If we identify that a child has a genetic disorder that can affect those other body systems, we might recommend that the child be evaluated for those medical risks. For example, a child identified with a genetic condition may be evaluated by specialists for heart or kidney problems.

Genetic diagnosis tells up what to expect

If we know there are specific health problems that are more likely in the future, we could recommend screening or evaluations for those medical risks. Establishing a genetic diagnosis can also allow us to give more information about prognosis or what to expect in the future. It can help answer questions like:

• Is this a condition that's going to be stable or would we expect it to get better?
• Is the child going to continue to gain skills and what is the expected variability?
• What is the range of developmental outcomes for a certain syndrome?

Sometimes with genetic disorders, there is a specific treatment. However, in many cases right now, there isn't a cure. We rarely can fix genes or fix chromosomes, but there could be a specific treatment such as a medication we know might help that child. Even if there's not a specific treatment to provide a child, we still could use that genetic diagnosis to help guide management and prognosis.