Hemifacial Microsomia (and Goldenhar Variant)


Up until fairly recently, this condition was called first and second branchial arch syndrome; even today, it sometime referred to by geneticists as oculoauriculovertebral syndrome. Hemifacial microsomia is thought to occur somewhere between 1:3,5000 and 1:5,000 births. The term craniofacial microsomia is sometimes used to describe individuals who also have involvement of the upper face and forehead.

At the current time, no specific gene has been identified that causes this condition, and it is very rare for someone with hemifacial microsomia to pass the trait on to his or her children. The exact cause of this condition remains unknown but there is some experimental evidence published many years ago suggested that if a small blood vessel ruptures near the developing ear in mice, before they are born, after birth they appear to have hemifacial microsomia. More likely, this condition results from an impaired flow of cells (called neural crest cells), which arise next to the spinal cord, and migrate to the face to form the facial skeleton; if not enough of these cells are able to successfully migrate to their intended location, that side of the face ends up being smaller.

Physical Traits