Microcephaly is a condition where a baby's head is much smaller than normal. It is most often present at birth (congenital). Most children with microcephaly also have a small brain and an intellectual disability. Some children with small heads have normal intelligence.
Microcephaly may be caused by problems during a woman’s pregnancy. These include:
In some cases, microcephaly may be caused by inheriting an abnormal gene. Microcephaly is an autosomal recessive gene disorder. Autosomal means that boys and girls are equally affected. Recessive means that 2 copies of the gene, 1 from each parent, are needed to have the condition.
Some genetic disorders that cause microcephaly are X-linked. This means the faulty gene is on the X chromosome. Girls can have the faulty gene on 1 of their X chromosomes but not have any signs or symptoms of the disease. They are carriers for the condition. Boys only have one X chromosome. If their X chromosome carries a faulty gene they will have symptoms.In some cases, microcephaly may occur after birth. This is known as acquired microcephaly. It can happen because of injury to the brain. This may be caused by lack of oxygen or an infection.
A child is more at risk if he or she has a parent or sibling with microcephaly, or who carries a faulty gene.
A child is also more at risk if the mother has problems in pregnancy such as:
Symptoms can occur a bit differently in each child. They may include:
Microcephaly may be diagnosed before birth by prenatal ultrasound. This imaging test uses high-frequency sound waves and a computer to make images of blood vessels, tissues, and organs. Ultrasounds let healthcare providers see the internal organs as they function. They also show blood flow through blood vessels. In many cases, microcephaly may not be seen with ultrasound until the third trimester.
After birth, the healthcare provider will ask about your child’s health history. He or she may ask about your pregnancy and health history, and your family’s health history. The provider will give your child a physical exam.
Your child may have tests, such as:
There is no treatment for microcephaly that will return the baby's head to a normal size or shape. Microcephaly is a lifelong condition that has no cure. Treatment focuses on preventing or reducing problems and maximizing a child's abilities.
The healthcare team will give support and teach you how best to manage your child’s health. Over time, your child may see healthcare providers such as:
Talk with your child’s healthcare providers about the risks, benefits, and possible side effects of all treatments.
Your healthcare provider may advise genetic counseling. You can learn more about the risk of microcephaly in a future pregnancy.
Parents who have 1 child with autosomal recessive microcephaly have a 1 in 4 (25%) chance for another child with microcephaly with each pregnancy. For X-linked microcephaly, mothers who are carriers have a 50% chance that a son will have the disorder. Daughters have a 50% chance of inheriting the gene and the same risk of passing it along to their children.
Also talk with your healthcare provider before and during pregnancy to minimize risks from:
The full range of issues are usually not known right after birth. Issues can revealed as a child grows and develops. Children born with microcephaly need to see their healthcare team often. They will need tests to track the growth of the head. Their motor, social, intellectual, and language function will be tracked over time.
You can help your child strengthen his or her self-esteem and be as independent as possible. Your child may need physical and occupational rehabilitation. He or she may need extra support in school. The healthcare team will talk with you about the best ways to help your child.
Call the healthcare provider if your child has:
Tips to help you get the most from a visit to your child’s healthcare provider:
Article Last Updated: February 12, 2019
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