A cleft chin (belonging to William McKinley)

Human jaw front view

A cleft chin, butt chin, chin cleft, dimple chin or a chin dimple is a dimple on the chin. It is a Y-shaped fissure on the chin with an underlying bony peculiarity.^[1] The chin fissure follows the fissure in the lower jaw bone resulted from the incomplete fusion of the left and right halves of the jaw during the embryonal and fetal development.^[2]

This is an inherited trait in humans, where the dominant gene causes the cleft chin while the recessive genotype presents without a cleft. However, it is also a classic example for variable penetrance^[3] with environmental factors or a modifier gene possibly affecting the phenotypical expression of the actual genotype.

[edit] See also

• List of Mendelian traits in humans
• Cleft chin murder

[edit] References