If I Stutter, Will My Child Stutter?

Genetics is one of the several causes of stuttering. Here’s what you should know about the heritability of stuttering in children.

Chances are, you’ve heard the phrase “It’s in my genes” a lot of times in your life. Genetics provides a simple answer to many complex questions, ranging from “How do you sing so well?” to “Why is your handwriting so bad?”

While genetics may not answer why some of us squiggle in the place of writing, there is a strong link between genes and stuttering.

The relationship between stuttering and genetics was not well-defined until recently. Stuttering is a speech disorder where a person repeats words, syllables or phrases. Stuttering typically begins in children between the ages of 2 and 5 years. It coincides with the rapid development of their language skills.

Initially, experts thought stuttering to be a result of the deformity of the tongue or larynx. The actual cause of stuttering was a mystery until the link between genetics and stuttering was established.

Understanding Developmental Stuttering

Before understanding the link between genetics and stuttering, it is crucial to note that one reason alone cannot justify stuttering. There are four types of stuttering: developmental, neurogenic, pharmacogenic, and psychogenic. Different factors are responsible for every single type.

The most common form of stuttering is developmental in nature. 5–10% of all children are likely to stutter at some point in their growth phase, mostly between 2 to 6 years of age. Though many outgrow it, nearly 20–25% of them (i.e. approximately 1% of all children) will continue to stutter.

Heredity (genetics) and environment, both play important roles in the development of stuttering. Nonetheless, studies show that heredity plays a more significant part in the precipitation of stuttering as compared to environment.

How Genetics and Stuttering Are Related

In 2005, a team led by molecular geneticist Dennis Drayna analyzed the genes of 46 families from Pakistan consisting of members who stutter. They found a specific region on chromosome 12 with a potential link to stuttering.

In subsequent research, Dr Drayna’s team was able to identify mutations in the GNPTAB gene among participants who stuttered.

The protein encoded by the GNPTAB gene helps in breaking down and recycling cellular components inside lysosomes. Lysosomes are enzyme-containing cell organelles. They are responsible for breaking down macromolecules and repairing cell membranes.

The researchers combed the DNA of the initially studied 46 families from Pakistan and over 600 others who stuttered. They found mutations in two other genes which work in liaison with the GNPTAB — GNPTG and NAGPA. According to the researchers, around 9% of people who stutter (PWS) have mutations in one of these three genes.

Will the Discoveries Help in Stuttering Treatment?

The findings of Dr Drayna’s studies have established a biological reason for stuttering. For many years, PWS had to deal with shame and guilt as they were made to believe that anxiety and shyness caused stuttering.

The latest findings strongly indicate that stuttering is a disorder with its roots in genetics. Recent developments in proteomics give us the hope that several lysosomal storage disorders (LSD), including stuttering, may soon have a cure. Recent publications on gene therapy for lysosomal storage disorders hold promise for the treatment of LSDs, including stuttering.

What Should A Parent Do?

For a new or would-be parent with stuttering, being anxious about whether your child will stutter is only natural. Since stuttering doesn’t depend on genetics alone, it is almost impossible to predict whether the child/children of parent(s) who stutter will also stutter.

Instead of worrying, gather authentic information on stuttering in children and treatment options. Early intervention by a professional can be of great help.

Make sure you are a good listener when your child begins talking. If your child is showing signs of speech disfluency, be sure to speak to them slowly. Do not rush them. Enunciate your words and when your child is particularly incoherent.

Make sure you don’t interrupt your kid while s/he is speaking.

Most importantly, consult a speech-language pathologist (SLP) if your child begins stuttering between the ages of 18 months and 5 years, and continues to stutter for longer than 6 months.

What Can We Conclude?

Statistics show that 70% of PWS have a family history of stuttering.

While these numbers show how genetics are related to stuttering, the research is still in its nascent phase and there is no way to ascertain that children of parents who stutter will also stutter.

Like every other disorder with a genetic basis, parents need to be vigilant for the signs and symptoms. Parents need to act quickly and as soon as the child begins showing signs of stuttering.

Stuttering in children, with or without genetic predispositions, is much easier to treat when intercepted by an SLP in the earliest stages.

Most importantly, don’t lose hope!

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