Gap teeth

Please note: Your Personal DNA Reports show genetic 'susceptibility' to traits, but not a direct relationship. As the majority of traits are influenced by environmental and lifestyle factors as well as your genes, you may find that not every result reflects your lived experience.

Have you ever wondered why some people have gaps between their teeth? Medically, this feature is called a diastema, meaning ‘interval’ in Greek translation. Like many dental features, diastema is heritable and specifically refer to gaps larger than 0.5 mm. These gaps are considered part of healthy dental development in children aged below 12 years [1] Jump to reference section: [1] . However, for inherited cases, they may continue into adulthood. 

Between 1.6% to 28% of adults have diastemas depending on heritage and ethnicity, with this trait occurring more often in African populations than White and Asian populations [2] Jump to reference section: [2] . Culturally, the midline diastema, a gap between the upper incisors, is perceived as a sign of beauty in African societies. Similarly, some people recognise the midline diastema as a unique feature shared by famous personalities like Elton John and Eddie Murphy [5] Jump to reference section: [5] . 

The genetics of gap teeth

Individuals with diastema inherit genes that affect the process of dental formation, including the number and arrangement of teeth in the gums. The likelihood that you have a diastema is linked to two categories of genes you may have inherited.

The first set of genes are those that cause a large lip frenulum. The frenulum is a thin line running across the area between the lip and the gum. Studies have associated a large lip frenulum with the formation of a gap between the upper incisors, also known as the midline diastema. However, studies have yet to establish the exact genes that cause enlargement of this line during an individual’s development.

The second category are genes that directly affect the arrangement of teeth on the gum, including spacing and number. These genes are associated with missing teeth and spaces between available teeth. This inborn condition, known as tooth agenesis, is one of the major causes of diastemas.

An initial study about the genetic basis of diastema has associated the trait with two main variants that affect the growth and spacing between teeth. Future studies are likely to confirm these relations and help discover more genetic changes related to diastema.

CACNA1S gene

The CACNA1S gene controls how the body uses calcium to enable movement of muscles and other body structures [3] Jump to reference section: [3] . During the formation of teeth, proper functioning of this gene ensures a healthy balance between tooth development and expansion of the jaw line. Genetic changes such as rs4498834 may affect the proper upward movement and positioning of teeth on the gum. In turn, this can create gaps. You are more likely to have developed your diastema as a result of this gene if you carry the C allele of the rs4498834 variant. 

ARHGAP15 gene

The ARHGAP15 gene is involved in processes that activate the growth of cells [3] Jump to reference section: [3] . The formation and development of teeth depends on these processes and is likely to be affected by related genetic changes. The variant rs2034604 interferes with the process, causing changes in tooth growth and size. The T allele of this variant is associated with missing teeth and gaps between teeth. 

What other factors can cause gapped teeth?

Apart from your genes, other factors you encounter as you grow may cause gaps between your teeth. For example, loss of primary teeth in children causes a temporary diastema which disappears once the secondary teeth grow. Gum disease can also cause the root of the tooth to become loose and lean sideways, causing a gap in the process, and habits such as thumb sucking can push teeth forward and create a gap between them. It’s also possible to develop a gap through an involuntary swallowing reflex, where the tongue presses against your front incisors. Teeth may gradually move outward as a result, causing a gap [4]. 

What can you do about it?

Treating diastema may not be necessary as they are harmless. However, if you feel it affects your appearance and want to change it, you may have it closed by your dentist. Common methods include using full braces to pull the teeth together, using veneers or bonding if you have smaller teeth,  implants to fill in for missing teeth, and surgery to reduce the size of the lip frenulum. To help prevent diastemas it’s also important to practice proper oral hygiene and habits. These may include overcoming thumb sucking behaviour in children, and regular tooth brushing of course! [4].