How much of our voice and speech is genetic?

Introduction

Our voices are as unique as our fingerprints! Although there are people whose voices might sound alike, there are no two voices exactly the same. Every person has their own characteristic voice that is distinct and different from everyone else’s. This allows us to easily recognize and identify a familiar person once we hear them. Nonetheless, what is the reason why every person has a distinct voice? Could it be our DNA that influences our voice? What is the connection between voice and speech, and how can a genetic disorder or lifestyle habit be associated with changes in our voice and ultimately affect our speech?

How is our voice generated?

Voice is generated from the airflow that comes from the lungs. First, the air from the lungs blows through the vocal cords at a high-speed, causing them to vibrate. The vibration produces a sound that is shaped by our mouth, nose, soft palate, and teeth when we exhale, to produce recognizable words. Articulators such as the mouth, nose, soft palate, teeth, and others are responsible for shaping the speech allowing us to produce recognizable words. Another essential part of the voice is the pitch, which is associated with the frequency of vibration of vocal cords. Pitch changes have been associated with voice disorders such as dysphonia or cancer (1).

Most of us use our voice to communicate, talk, sing, and express emotions, but the reason why every person has a different voice is complicated and depends on many factors. One factor is hormones. Sex hormones, testosterone in males and estrogen and progesterone in females, can change the physiology of the laryngeal tissues and vocal cords–especially during puberty–resulting in voice alterations. This is especially noticeable in males in which voice breaking is observed (2). Additionally, environmental and lifestyle factors such as smoking, allergies, aging, pollution, dry air, and alcohol use have a role in shaping each person’s voice (3, 4, 5). Another major factor is genetics, which can influence the quality of the voice since it can be responsible for the physiology and the structure of the larynx, as well as other structures responsible for voice and speech production (6).

The “language gene”, FOXP2

The FOXP2 gene, identified in 2001, was the first gene to be linked with speech and language (7). It encodes for a protein called forkhead box P2 and can be active in different tissues including the brain. The main role of the protein is to control the function of other genes that regulate brain development, the growth of neurons, and the signal transmission between them, as well as the development of speech and language in humans. Changes in this gene–known as mutations or variants–have been found to be associated with speech-language disorders, including developmental verbal dyspraxia (7, 8).

The “high pitch” gene

Interestingly, a study in 2023 revealed that the pitch of the voice might be determined by variants in the ABCC9 gene. About 13,000 Icelanders participated in this study by recording and analyzing their speech, as well as sequencing their genome. Results showed that individuals with specific ABCC9 variants had higher pitch voices. In addition, these variants have been linked to higher pulse pressure, which is a cardiovascular risk marker, suggesting a potential association between cardiovascular traits and high-pitch voice (9).

Disorders and syndromes associated with voice changes, speech delays, and language impairments

Evidence shows that genetic factors can be associated with speech and language disorders. Indeed, there are different genetic disorders that have been linked to voice changes, speech difficulties and delayed speech during infancy. Some examples include:

Developmental verbal dyspraxia

Developmental verbal dyspraxia, also known as childhood apraxia of speech, is a rare disorder in which children have difficulty controlling the muscles of the face, lips, tongue, and soft palate to produce clear speech. Children affected have difficulty in organizing voice and breathing patterns, as well as producing repeated syllables and disrupted sounds due to the inability to transition between sounds. Additionally, difficulties in understanding language, and social interaction have been observed in children with this disorder (10). The most common mutation associated with this disorder is found in the FOXP2 gene (7). The mutated gene can be passed down from parents to children in an autosomal dominant manner, which means that only one parent is required to have the mutated gene for the children to have a risk of being affected. Speech and language therapy is recommended for children with developmental verbal dyspraxia.

Specific language impairment syndrome

Specific language impairment, also known as developmental language disorder, is a disorder that affects language development. The syndrome is diagnosed at a young age when children having difficulties learning how to talk, delays speaking, and problems understanding complex language (11). The exact cause of specific language impairment is unknown; however, it is suggested that there is a genetic link. Examples of genes found to be associated with this syndrome include FOXP2, CNTNAP2, ATP2C2, and CMIP (12). Clinical management for people with specific language impairment syndrome includes speech and language therapy to improve communication skills and delay the development of symptoms.

Huntington’s disease

Huntington’s disease is also associated with voice and speech impairment. This is an inherited neurological disorder that causes the nerve cells in the brain to gradually break down and die. Huntington’s disease is caused by mutations in the HTT gene that produces the protein huntingtin that is important in neuron normal functioning. Patients with Huntington’s disease have different symptoms including loss of coordination in the throat muscles–also known as dysarthria. This results in changes in the speech and hoarseness of the voice, as well as the inability to control the voice volume and other changes. Additionally, as the disease progresses, the symptoms might get worse with the potential loss of speech organization and other communication issues (13, 14).

DiGeorge syndrome

DiGeorge syndrome is a genetic condition that is characterized by a small deletion, known as microdeletion, of a piece of DNA in chromosome 22. This genetic change results in the loss of about 50 genes affecting embryonic development and causing congenital anomalies (15, 16). Additional characteristics of DiGeorge syndrome are communication and speech delays, learning disabilities, voice disorders, and laryngeal anomalies (17).

Ehlers-Danlos syndrome

Ehlers-Danlos syndrome is a group of genetic diseases that affects the connective tissues of the body. Genes associated with Ehlers-Danlos syndrome include COL1A1, COL1A2, and COL5A2, among others. Patients can have different symptoms, such as joint hypermobility (18). The syndrome also affects the larynx which leads to changes in the voice, such as hoarseness, dysphonia, difficulty speaking, and bleeding in the vocal cords (19, 20).

Other causes of voice changes

In addition to the disorders and syndromes that are linked tovoice changes and speech impairments, some people might experience voice changes due to other reasons. Examples include:

Laryngeal cancer

Changes in the pitch and intensity, as well as hoarseness in the voice, can be a sign of laryngeal cancer. This is a type of neck and head cancer which starts in tissues of the larynx. When a tumor touches the vocal cords it can lead to persistent voice changes but also in difficulties in swallowing, sore throat, and dysphonia. Different treatments are available for laryngeal cancer, such as targeted therapy (21).

Polyps and nodules on vocal cords

Polyps, nodules, and cysts can be found on vocal cords. They are benign, non-cancerous growths that prevent the vocal cords from vibrating normally. They can be caused by voice overuse, constant coughing, allergies, or other risk factors. Symptoms include hoarseness, loss of voice and vocal range, and a raspy or scratchy voice (22). Vocal cord nodules are common in singers, and they are known as “singer’s nodules”. They can form if someone is misusing or overusing their voice, and can be treated with voice therapy, or surgery (22).

Thyroid problems

Voice changes have also been linked with thyroid problems. For example, hypothyroidism can lead to lower voice, roughness, reduced range, and vocal fatigue (23). With hypothyroidism, the thyroid gland does not produce enough thyroid hormones, which affects the voice. Hyperthyroidism–_­in which there is excess production of thyroid hormones–can lead to mild voice changes, including decreased volume, and a “shaky” voice (24). In addition, thyroid cancer can also be responsible for voice alterations since nodules or growths on the thyroid gland can lead to pressure in the larynx and vocal cords, resulting in hoarseness and changes in the voice pitch (25).

Other reasons

Other factors that can affect the voice include smoking, excessive alcohol intake, aging, allergies, and viral infections that might cause acute laryngitis (26).

How can genetic testing help people who might experience voice changes?

Undoubtedly there is a strong link between genetics and voice. Although genetic testing cannot be used as a “talent test” to discover potential singers or identify a person’s unique voice characteristics, it can help in identifying the reasons a person might have voice changes, such as in the case of an inherited genetic syndrome. Additionally, in certain cases, genetic testing can help in identifying better treatment approaches such as in patients with laryngeal cancer, where early diagnosis increases the possibilities of a successful treatment and better clinical management.

Conclusion

Our voice and speech are fundamental parts of our everyday life. While our voice allows us to communicate, talk, and express emotions and feelings, it can also be associated with genetic syndromes, disorders, and other diseases that might affect our ability to communicate. The genetics of voice are clearly complicated and further investigation is needed to understand the role of the DNA in voice and speech generation.

The content of this article is for informational purposes and is not intended to replace medical advice. Please visit your healthcare provider if you have concerns about your health and well-being.

References

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