Step 3: Syndrome Description

So far, we have gathered information about the effects of chromosome changes through (a) a literature review, and (b) a thorough series of clinical assessments. Now, it is time to pull together a syndrome description. This description is a comprehensive collection of all the different things that we’ve found in a group of people with a particular chromosome change. Some things might be quite common, such as strabismus in people with tetrasomy 18p. Other things might be seen in a minority of individuals, such as holoprosencephaly in people with 18p-. Other things might only be reported once, and it is unclear whether it is a consequence of the chromosome change, or perhaps it is completely unrelated to the chromosome change.

Once we’ve got the syndrome description, what do we do with it? Well, the first thing we want to do is share our description with others. We can do this in a couple of different ways. We write scientific papers for publication in medical journals to share information. We make presentations at various scientific conferences. We also share information with patient advocacy groups. In our case, this is mainly through the Chromosome 18 Registry’s website as well as at the annual Registry meeting.

The syndrome description gives families and providers an idea of what kinds of issues and concerns may arise in someone with a particular chromosome change. This gives them an opportunity to screen for problems, prepare for various possible outcomes, and just have a better idea of what kinds of things might pop up as a person ages. However, as most parents will tell you, a syndrome description is useful, but it most certainly is not the end-all, be-all. Although we are able to describe the different features that have been seen in people with chromosome changes, we cannot predict precisely who will get which features. There are still several steps that must be completed before we are able to provide personalized information based on a person’s specific genetic change.

Once we are able to fully describe the range of features that are associated with a condition, we can then start to figure out which ones are associated with different breakpoints. For example, we can ask questions such as, “What is different between people who have a breakpoint in 18q23.1 versus those with a breakpoint in 18q12.3?” In fact, this question leads us directly into the next step on the path to treatment: gene identification.