Microcephaly in children

What is microcephaly in children?

Microcephaly is a rare condition that occurs when a baby’s head and brain are smaller than normal for the baby’s age. It can result from infections or very rare genetic syndromes.

Microcephaly comes from “micro,” meaning small, and “cephaly,” meaning head. The term describes a baby’s head that is smaller than expected compared to other babies of the same gender, ethnic background and age.

The size of a baby’s head is largely determined by brain growth. If something causes a baby’s brain to develop abnormally in the womb, the baby's head may be smaller than is typical.

A smaller brain can cause developmental and intellectual difficulties. Microcephaly can range from mild to severe.

What are the signs and symptoms of microcephaly in children?

In most cases, the only early sign of microcephaly is a small head (skull) size. However, many babies born with microcephaly don’t have any symptoms at birth.

Other symptoms include:

• Feeding difficulties or failure to thrive

• Hearing and vision problems

• High-pitched crying

• Movement and balance problems

• Seizures or muscle spasm

Later in life, they may develop complications such as:

• Cerebral palsy

• Epilepsy (seizures)

• Head or facial deformities

• Hearing loss

• Learning disabilities

• Vision problems

How is microcephaly in children diagnosed?

During pregnancy

Most commonly, your OB-GYN diagnoses microcephaly during your pregnancy, at an 18 to 20-week ultrasound scan. During this scan, the sonographer takes detailed measurements of your baby’s anatomy and compares them to expected standards.

After birth

In some cases, microcephaly develops after birth. Pediatricians and other providers track your baby’s growth and development. By measuring your child’s head size at each well-child visit over the first few years of life, a pediatrician can detect microcephaly that occurs during early childhood.

Your child’s pediatrician will also take into account if:

• The head is proportionate to the baby’s body size

• Other family members have a smaller head size

• Your child has other abnormalities, such as vision impairment, seizures or developmental delay

To diagnose the cause of the microcephaly, your child’s doctor may order tests such as:

• Blood tests

• CT scan

• MRI scan

Genetic testing for microcephaly in children

If other family members have microcephaly, we may recommend genetic testing to understand the cause. Certain syndromes are recessive, meaning that a baby inherits one gene from each parent. The syndrome doesn’t affect mom or dad, but when those two genes come together in a baby, they can cause disease. These syndromes are some of the most common ways for a child to inherit microcephaly.

At Children’s Health, we may perform genetic testing called a chromosomal microarray. This test examines your baby’s DNA for common disorders that can cause microcephaly. Your family can meet with a pediatric geneticist and genetic counselors to discuss appropriate screening tests. They also discuss your future family planning and other considerations that might be important for your family.

What causes microcephaly in children?

Microcephaly itself is not a disease. Instead, it is a sign of another underlying problem. In many cases, no one will ever know what caused microcephaly in a child. It’s not usually due to anything you did or didn’t do as a parent.

Genetic causes

The primary cause of microcephaly may be an inherited genetic condition (congenital microcephaly). Many of these conditions are very rare. Families usually don’t even know they have the gene. These include:

• Inherited chromosomal abnormalities, including Down syndrome

• Microcephaly vera disorder, a type of autosomal recessive disorder (a child inherits two genes with the mutation)

• Rett syndrome

• Other neurodegenerative disorders

Causes during pregnancy

• Cerebral anoxia - which is decreased oxygen to the baby’s brain

• Craniosynostosis - when plates in the skull close too early

• Drug or alcohol exposure - especially alcohol, cocaine or opiates

• Exposure to toxins - or hazardous chemicals

• Infections in the pregnant mother - such as chicken pox (varicella), cytomegalovirus (CMV), HIV, rubella (German measles), syphilis, toxoplasmosis or Zika

• Maternal health problems - like severe malnutrition or untreated PKU (phenylketonuria)

Conditions after birth (acquired microcephaly)

• Lack of oxygen to the brain (hypoxic ischemic injury)

• Brain injury that makes it harder for the brain to grow

How is microcephaly in children treated?

At Children’s Health, we treat babies with microcephaly in utero (before birth) or after birth.

Care during pregnancy

If we learn your baby has microcephaly in utero, we refer you to our Fetal Evaluation and Treatment Alliance (FETAL) Center.

You’ll have access to prenatal consultants from a wide variety of medical specialties including:

• Neurology (brain conditions)

• Pediatric genetics

• Neonatal intensive care doctors

We can arrange for a fetal MRI imaging exam. Fetal MRI provides highly sensitive 3D imaging of your baby’s head and brain to confirm a diagnosis.

Care at birth and beyond

Our neonatal neurology doctors meet your baby right after birth, in the nursery or pediatric NICU. We follow your baby’s care long-term in our outpatient clinic. Throughout your baby’s life, we provide holistic, family-centered care.

If your baby has related conditions, we offer treatment for those problems, such as:

• Seizures - We treat seizures with medications and state-of-the-art alternative treatments such as a ketogenic diet, vagal nerve stimulation or cannabidiol. Our pediatric neurology group includes epileptologists (doctors specially trained in neurology and treating and evaluating epilepsy). If a child isn’t responding to multiple medications and treatments, we may refer them to our Pediatric Epilepsy Center for evaluation.

• Hearing loss and vision problems - Specialists offer therapies to optimize your child’s development in these areas.

• Developmental delays - Neurologists may recommend therapies to improve your child’s development and help them walk, talk, interact with others and learn self-help skills.

In most cases, microcephaly has no specific treatment.

Microcephaly surgery

In some children, microcephaly happens because the skull bones close too early or fuse together. We can refer your family to our craniofacial and plastics specialists to discuss your options. These surgeons specialize in reconstructive surgery. They can perform procedures to help separate fused bones, so your child’s head and brain have room to grow.

Advanced microcephaly care

Through Children’s Health’s partnership with the research scientists at UT Southwestern, we can offer families access to highly sophisticated gene therapy and research options. In some cases, we have been the first in the world to pioneer these gene therapies.

Our team works together to understand the mechanism of what’s causing microcephaly and related disorders. Then we develop new treatments to create research trials where families can access those treatments.