You'll find hundreds of files on cleft lip, cleft palate here on

This one is about: The Three C's of Etiology

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by Joanne Green

Any time a child is born with a birth condition, one great question is typically on the lips and minds of the parents: "Why?" What caused this to occur to my baby? What made this happen? When we ask these questions what we are asking is, in fact, what is the etiology of this condition? And, in the case of an isolated cleft, the etiology is often unknown. We simply don't always have an easy answer. Explanations can be confusing. One time you hear that one thing caused your child's cleft.  Another time you hear that something else caused it. Who is right? And how can there be so many answers to one question?

To help unmuddle some of the confusion, let's discuss what I like to call the "three C's of etiology". Cause, Contribute and Correlate. Each term refers to factors that may have had something to do with the appearance of the condition.

CAUSE is simple to understand. It means that there is a proven cause-and-effect relationship between the two factors. For instance, boiling water on bare skin causes burns. (When A happens, we observe the B happens too because A contributes all the ingredients necessary for B to occur.)

My son was born with Constriction Band Syndrome. That means that he was entangled in the fibrous tissues of the placenta before birth. We can assume that those same tissues, and/or other complications related to the Amniotic condition of my son's gestation, somehow interrupted the development of his face. Therefore, if our assumption is correct, the absence of an amniotic sac and resulting fibrous tissues of the placenta CAUSED my son's cleft.

Some factors are not so simple. Contribute is less cut-and-dried. CONTRIBUTE means that this factor, in the presence of other factors, can lead to the condition in question. For instance, stress, along with a high-cholesterol diet as well as a genetic predisposition CONTRIBUTES to heart disease. (When A happens, B sometimes happens because A, when added to other factors in combination, may lead to B).

Studies have been done that show a higher percentage of children born with cleft to mothers who smoke cigarettes just prior to and during the first trimester of the pregnancy. Cigarette smoking may not have actually CAUSED the clefting to occur, but rather CONTRIBUTED to its occurrence, taking into mind other factors, such as genetic predisposition, maternal age, ethnicity, prenatal history, diet, drug use, etc.

Still other factors are simply CORRELATED to the condition. That means that for reasons we may not know, the condition and a particular factor appear to occur at the same time. One may not be casually related to the other at all, but rather they both may be related to a third factor. For instance, a cold virus may cause a runny nose and a sore throat. The runny nose does not cause the sore throat, nor does it contribute to the sore throat, nor visa-versa. They are both related (or co-related) to the same causal factor - the cold virus. (When A happens, B often happens because factor C is present and related to both A and B.) For example, clefts seem to occur more often among Asian Peoples. Being Asian does not CAUSE a cleft, nor does it CONTRIBUTE to the cleft. Both are probably related to a third factor, sometimes theorized to have something to do with the shape of the facial structure (Asians tend toward a particular facial structure, and that facial structure tends toward clefting conditions.)

If you gave birth to a child with a cleft you no doubt asked the perennial question: "Why?" You no doubt also got a lot of answers in response. Don't bog down in all this. Keep whatever information you have, use what you can. File the rest.

If you have already given birth to a child with a cleft and want to become pregnant again, there is something you can do. With the help of your geneticist, identify any possible CAUSES of the cleft that may affect you and do what you can to remove them if at all possible, By identifying CORRELATES you will be able to identify whether or not you fall into a high-risk category. Look for those factors that CONTRIBUTE to clefting and remove them also. In so doing, you are not guaranteeing that you will not give birth to another child with a cleft. You are, however, reducing the risk.

CAUSALITY, CONTRIBUTION, and CORRELATION will be somewhat different for every set of parents. When you need a complete understanding of your risk factors, your genetic counselor is your best resource. Ask questions and understand how each factor in your life contributes to your degree of risk. Unfortunately, there are few if any cut-and-dried answers out there for many of us. In the end, we simply have to take what we know, add in the unknown, try to determine what the probabilities are, and then make our decision and hope for the best.

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