Understanding Hemifacial Microsomia (HFM) 

How to say it

hem-ee-FAY-shul

my-kro-SO-mee-uh 

What causes hemifacial microsomia? 

HFM often happens by chance. It can develop during pregnancy at around 4 weeks of a baby’s growth. It occurs because of problems with blood vessels that don’t let enough blood flow to the face. 

It may also run in some families. HFM may be passed on (inherited) through a faulty gene in these ways:

• Autosomal dominant. This means that only 1 parent passes the gene on to the child. Each child has a 1 in 2 chance of having the condition.

• Autosomal recessive. This means that both parents must have the gene to pass it on. Each child has a 1 in 4 chance of having HFM.

• Multifactorial. This means that many factors are involved. The factors are often genetic and external, such as injury during pregnancy. 

This condition may also occur in children who have other chromosome problems. Chromosomes are the structures in our cells that carry our genes. These types of problems often occur by chance. 

Symptoms of HFM 

Symptoms can occur a bit differently in each child. They may range from mild to severe. Areas of one side of the face may have less growth and be shaped differently, such as:

• Outside and middle of the ear

• Side of the skull

• Bone around the eye

• Thickness of the cheek

• Upper and lower jaws

• Teeth 

The condition may also affect some of the nerves in the face. This can cause weakness and problems with moving parts of the face. In some cases, other parts of the body may also be affected by HFM. 

Diagnosing HFM 

A geneticist may diagnose HFM. This is a doctor with extra training to diagnose and treat conditions passed down in families (genetic conditions). The doctor will look at your child’s health history. They will give your child a physical exam. Your child may also have tests such as:   

• X-rays of the head. X-rays use a small amount of radiation to show tissues and bones inside the body.

• CT scan. A CT scan uses a series of X-rays to show detailed images of the body. Your child may need a CT scan of the head. This test will show your child's bones, muscles, and other tissues. 

Treatment for HFM 

If your child has severe facial changes, they may need several surgeries. In this case, your child will be checked by a craniofacial anomalies team. This is a group of healthcare providers who diagnose and treat problems of the face. 

This team may include:

• A craniofacial surgeon who can do jaw surgery and ear reconstruction

• An ophthalmologist to diagnose and treat eye and vision issues

• An orthodontist to check and treat jaw growth and position

• An ear, nose, and throat doctor (ENT or otolaryngologist) to check hearing loss

• A speech therapist to help with speaking problems 

Your child’s treatment may include:

• Fixing your child’s lower jaw, using a bone graft taken from your child’s ribs

• Using a device to change the shape of your child’s jaw

• Surgeries to fix your child’s ear or cheeks

• Removing or changing the position of your child’s teeth 

Possible complications of HFM 

If your child has mild facial changes, they may not be at risk for complications. Children with more severe changes may be more likely to have issues. These can include:

• Hearing loss

• Eating problems

• Trouble with self-image 

Helping your child live with HFM 

HFM support groups can help you and your child. Ask your child’s healthcare provider about support groups in your area.

When to call your child’s healthcare provider 

Call the healthcare provider if your child has:

• Trouble eating

• Trouble gaining weight

• Other new problems