Almost every discussion of congenital abnormalities will at some point touch on genetics, the field of biology that attempts to explain why, and how, traits are passed from parents to children.
After delivering a child with cleft palate, most parents think first of treatment, of protecting their child’s well-being above all else. But once orthodontic devices and surgical repairs have been discussed with pediatricians, and a baby’s comfort has been taken care of, many families begin to ask deeper questions.
Foremost among these questions: why did this happen? How was my child born with a cleft palate? At their foundation, these questions deal with genetics, and the complicated world of heredity.
Cleft Palate: Are Genetic Factors At Work?
Yes, researchers believe that genetic predispositions play a part in causing most congenital abnormalities (commonly called “birth defects”), including cleft palate. In theory, that means cleft palate is hereditary, a trait that can be passed from mothers and fathers to their babies.
What we’re really saying here is that genes help determine the formation, function and physical appearance of every body structure, including the mouth and palate. Genes contain information, instructions that tell the body how to develop. Along with other factors, genetic information causes one palate to be smooth and continuous and another palate to stop growing completely, leaving a cleft.
In practice, though, genetics are a lot more complicated than that. Let’s compare two statistics to get a handle on this idea.
There’s No Bright Line From Genes To Phenotype
Parents who have orofacial clefts themselves are at a higher risk of having children with clefts. That sounds pretty hereditary, as if parents are simply passing along genetic information and that information has a direct effect on their children.
But the risk, even for parents with clefts, remains relatively low. Compared to any random parent, who has a .17% chance of having a child with a cleft, parents with clefts have between a 2% and 5% chance of having a child with cleft palate, according to CleftLine.org. That means the vast majority of parents with cleft palates won’t have children them. On the other hand, there are plenty of parents without a family history of orofacial clefts who have children with a cleft palate.
Obviously, there’s no straight line from your genetic makeup to your child’s phenotype, how your child will look when they’re born.
What Complicates Things?
Alongside genes, and playing an active role in the development of every fetus, are thousands of environmental factors, many of which may be able to alter how genes work or even directly impact the growth of organs. External influences, like industrial chemicals, illegal drugs and alcohol, even some pharmaceutical drugs, can impact the development of a fetus.
“Fetal programming” is the well-founded theory that conditions inside the womb, like its temperature, the amount of amnyotic fluid and substances carried in maternal blood, can change how fetuses grow, effects that are probably more pronounced at crucial early phases of development.
Genes Change – All The Time. So Does Environment.
For their own part, genes can mutate.
Every cell in the human body (the average adult is made up of about 37.2 trillion cells) contains genetic information in the form of DNA, but it didn’t start like that.
At the very beginning of conception, there’s only one cell: a zygote, made after one sperm merges with one egg, combining genes from mother and father. That early zygote begins to divide, according to the instructions of its DNA, copying the genes over and over and over. In the course of copying, little mistakes change the information, and thus the instructions. That’s one possible cause for some cleft palates, a genetic mutation.
Most researchers believe that an interplay between genetics and environment are at the root of most congenital abnormalities. For some children, a tiny genetic mutation may have started the ball rolling, but needed a trigger from the outside to continue the process.
All life, human or otherwise, begins with genetic information. Genes are largely responsible for determining how we look when we’re born, how we grow and what we’re capable of as we age. That’s why studying genetics in some detail (like with one of MIT’s free online courses) can be a great place to begin considering why particular children are born with cleft palates.