KidsMD Health Topics


  • Microcephaly Overview

    The human brain is a powerful organ with an amazing ability to process information, master complex behavior and create works of art, science and literature. However, while developing in infancy, the brain is also very vulnerable: even slight disruptions can have serious long-term results.

    When a child has microcephaly, abnormal brain development results in an abnormal head size – much smaller than other children of the same age. (“Micro” means “small,” while “cephaly” comes from the Greek word for “head.”) These complications can also lead to problems with a child’s cognitive abilities and neurological functions.

    Here are some of the key facts about microcephaly:

    • It can be congenital – meaning present at birth – or it can occur later during infancy.
    • It is relatively rare, affecting about 25,000 children in the U.S. each year.
    • It can be an isolated condition, or it can be associated with another medical problem.
    • It often (but not always) causes learning disabilities and other neurological issues.

    Unfortunately, microcephaly is a lifelong condition that cannot be cured. However, there is hope: Advances in neurological care have made possible new ways of managing a child’s symptoms, allowing a child to achieve and enjoy an optimal quality of life.

    How Children’s Hospital Boston approaches microcephaly

    Children’s has a long and distinguished history of caring for children with complex diseases and disorders of the brain, spine and central nervous system. Clinicians in our Department of Neurology and Department of Neurosurgery are regarded as international leaders in understanding and treating rare conditions like microcephaly.

    In particular, our Fetal-Neonatal Neurology Program specializes in diagnosing, studying and managing microcephaly and a broad spectrum of other conditions that affect newborns’ brains. Our expert care team includes:

    • neurologists, doctors with extensive training in diseases of the nervous system
    • developmental psychologists, doctors who study the mental and behavioral health changes children experience as they grow
    • nurses with significant experience in the neurosciences
    • social workers, who provide counseling and offer emotional and psychosocial support

    At the same time, doctors and researchers in our Division of Genetics are working hard to understand how and why microcephaly develops, in hopes of one day introducing new therapies – and the chance of a cure.

    Did you know?

    Boston Children's Hospital has been ranked #1 in the nation in pediatric neurology and neurosurgery by U.S. News & World Report. Learn more.

    Microcephaly: Reviewed by Janet S. Soul, MD
    © Children’s Hospital Boston; posted in 2011

    Some cases of microcephaly lead to difficulties with neurological functions and physical complications, like seizures and facial deformities. For these children, treatment is geared toward managing the complications of microcephaly rather than the condition itself through our Neurology Department. 

    Boston Children's Hospital
    300 Longwood Avenue
    Fegan 11 and Hunnewell 2
    Boston MA 02115

    Some cases of microcephaly lead to serious learning and speech disabilities. Speech therapy, to help improve language, voice and swallowing skills is offered through the Speech-Language Program in our Center for Communication Enhancement.

    Boston Children's Hospital 
    300 Longwood Avenue
    Boston MA 02115

  • Microcephaly In Depth

    Microcephaly is a neurological condition that occurs because a child’s developing brain doesn’t grow properly. This causes the disease’s most obvious physical symptom: a head size that is much smaller than normal.

    Because the brain does not grow at a normal pace, the skull doesn’t, either. Many (but not all) children with microcephaly also experience cognitive delays and neurological problems as a result.

    • Microcephaly is often (but not always) congenital, meaning it is already present at birth.
    • Other times, a child is born with a normal brain and skull, but then his brain fails to develop properly during his infancy.
    • A traumatic brain injury or infection can also lead to microcephaly.
    • Microcephaly is relatively rare, affecting about 25,000 children in the U.S. each year.

    Some children with microcephaly have normal intelligence and experience no particular difficulty with schoolwork, physical activity, relationships or any other aspect of their lives. However, many children with the disease – especially those with more severe cases – face:

    • mild to significant learning disabilities
    • impaired motor functions
    • difficulty with movement and balance
    • speech delays

    They can also have other medical problems, like:

    Although it’s not possible to restore a child’s brain and skull to normal size and appearance, treatment for microcephaly can make a significant difference in helping him with any medical, neurological and emotional symptoms he might be facing. 

    Here at Boston Children’s Hospital, our expert neurological and neurosurgical teams are fully equipped to assist your child – and each member of your family – at every step of the way.

    Spotlight on: Neonatal & Congenital Anomaly Neurosurgery

    Boston Children's Department of Neurosurgery specializes in complex procedures for newborns - and fetuses still in the womb - with disorders of the brain and nervous system.


    What causes microcephaly?

    There are a number of possible causes:

    • Most of the time, it happens because of an inherited defect in a gene that interferes with the brain’s maturing and growing.
    • There is evidence that, in some cases, microcephaly is caused by something that affects the mother during pregnancy. These factors can include:
    • substance abuse
    • inadequate nutrition
    • untreated phenylketonuria (PKU)
    • exposure to certain viruses – especially chickenpox, rubella (German measles) or cytomegalovirus
    • exposure to toxic chemicals
    • A baby can also be born healthy, but then acquire microcephaly because of:
    • a brain injury
    • lack of oxygen to the brain
    • an infection in the brain
    • Finally, microcephaly can be related to another disorder, such as:
    • Down syndrome and other chromosomal disorders
    • certain neurometabolic disorders 

    Signs and symptoms 

    What are the symptoms of microcephaly?
    The main symptom of microcephaly is a head size that is much smaller than normal for the child’s age and gender.

    Other symptoms can vary widely from child to child. They might include:

    • failure to thrive
    • poor appetite/feeding
    • unusually high-pitched crying
    • spasticity (involuntary muscle contractions)

    Not every child with microcephaly will display noticeable symptoms beyond a small head size. You should always seek a diagnosis from a qualified medical professional.


    Q: Will my child be OK?
    Your child’s exact prognosis depends on her specific symptoms and circumstances. Your treating clinician is the best source of information about her long-term outlook.

    However, it’s important to remember that – while microcephaly cannot be cured altogether – it is treatable. Not every child experiences neurological complications, and even in the most severe cases, there are treatment options that can help your child feel and function better.

    Q: Is microcephaly always evident at birth?
    No, not always. While many babies with microcephaly have a visibly small head size at birth, many others appear normal and don’t begin showing signs until their first few weeks or even first few months of life.

    Q: Are there different types of microcephaly?
    Microcephaly is classified according to its severity. The most seriously ill children will experience significant learning and memory problems. They may also have physical complications, such as seizures.

    However, some children with microcephaly experience almost no noticeable symptoms: While their heads are smaller than average, and they may be shorter in stature than most children their age, they have normal intelligence and can do everything their peers can.

    Q: Does microcephaly always cause complications?
    No. Many children with the disorder have problems with learning, memory, speech or movement. However, others will never develop any complications beyond their noticeably small head size.

    Q: Is there any way to prevent it?
    A: When microcephaly is genetic – caused by a defect in an inherited gene – nothing can be done to prevent it.

    If there is no genetic link to the disease, expectant mothers can lessen their chances of having a baby with microcephaly by avoiding the following during pregnancy:

    Q: Can microcephaly be detected during pregnancy?
    If your child has the congenital form of microcephaly – meaning it is caused by an inherited defect in his genes – it might be possible to detect the disorder with a prenatal ultrasound during the third trimester of pregnancy.

    Q: If my child has microcephaly, do I need to be screened before any future pregnancies?
    Whether you should be screened for microcephaly depends on the cause of your child’s disease: If his microcephaly is related to a type of brain injury, for example, genetic screening would not be useful.

    If your child is believed to have congenital microcephaly (present at birth) that is caused by an inherited defect, genetic counseling is very advisable as you plan to add to your family.

    Q: Besides medical treatment, what types of support might my child need as he grows?
    The exact support your child will require depends on his specific symptoms and the severity of his disease. Your treatment team will advise you on the best resources to meet your child’s needs.

    In general, children with microcephaly can benefit from:

    Did you know?
    In addition to diagnosing and treating brain disorders in babies, the experts in Boston Children's Fetal-Neonatal Neurology Program are also working hard to uncover new insights into these diseases.

    Questions to ask your doctor

    You and your family play an essential role in your child’s treatment for microcephaly. It’s important that you share your observations and ideas with your child’s treating physician, and that you have all the information you need to fully understand the treatment team’s explanations and recommendations.

    You’ve probably thought of many questions to ask about your child’s symptoms and prognosis. It’s often very helpful to jot down your thoughts and questions ahead of time and bring them with you, along with a notebook, to your child’s appointment. That way, you will have all of your questions in front of you when you meet with your child’s treating clinician and can make notes to take home with you.
    Initial questions to ask your doctor might include: 

    • How did you arrive at this diagnosis?
    • Are there any other conditions my child might have instead?
    • Are there any other related conditions my child could have?
    • Does my child require further testing or procedures?
    • How extensive is the damage to his neurological function?
    • What medications will you prescribe and what are the possible side effects?
    • What adjustments need to be made in his home and school routines?
    • How should I talk about my child’s condition with him as he gets older?
    • How should I explain my child’s condition to others?
    • Should I be screened as a carrier for this condition?
    • What other resources can you point me to for more information?
  • Tests Used to Diagnose Microcephaly

    The first step in treating your child is forming an accurate and complete diagnosis.

    How is microcephaly diagnosed?
    If a baby has congenital microcephaly – inherited through a genetic defect – it may be possible to diagnose his condition while he is still in the womb, through a prenatal ultrasound. (The test should only be performed in the third trimester, since a fetus’ smaller-than-normal head size is usually not obvious earlier in pregnancy.)

    For children who develop signs of microcephaly later in infancy, doctors typically make a diagnosis by:

    • obtaining a full medical and family history
    • performing a complete physical exam
    • measuring the circumference of the baby’s head (and continuing to take measurements as he grows, in order to compare his measurements to the average for his age and gender)
    • measuring the heads of his parents (to determine whether it may simply be the case that smaller head sizes “run in the family,” rather than the child having microcephaly)

    If a child has microcephaly that involves some degree of learning disability or other impairment, doctors may also order the following tests to confirm the diagnosis:

    After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options.

    One family's story

    Addison Lennon met all her early milestones: she sat up on time, crawled on time and walked on time.  At about 4 months, however, she had a seizure, and her parents started to worry. By 9 months, her head appeared small for her age.

    Learn how Boston Children’s made a difference for Addison, her parents and her siblings.

  • Microcephaly Treatment

    Here at Boston Children's Hospital, we specialize in innovative, family-centered care. From your first visit, you'll work with a team of professionals who are committed to supporting all of your family's physical and psychosocial needs.

    What are the treatment options for microcephaly?
    Microcephaly is a lifelong condition for which there is no cure. Some children with the disorder don't experience any difficulties beyond a smaller-than-normal head size (and possibly a smaller-than-average height): They don't need  any treatment beyond routine check-ups and ongoing head measurements.

    However, the effects of the disease vary a great deal from child to child: Some cases of microcephaly lead to serious learning and speech disabilities, difficulties with neurological functions and physical complications, like seizures and facial deformities. For these children, treatment is geared toward managing the complications of microcephaly rather than the condition itself.

    Boston Children's Hospital is home to a multidisciplinary team of experts who are dedicated to providing all of the support, assistance and information your child and family need. Your treating clinician will work with you to formulate a customized treatment plan that helps your child reach his fullest potential in school, at home and in his relationships.

    Besides medical treatment, what types of support might my child need as he grows?
    The exact support your child will require depends on his specific symptoms and the severity of his disease. Your treatment team will advise you on the best resources to meet your child's needs.

    In general, children with microcephaly can benefit from:

    Did you know?
    Christopher Walsh, MD, PhD, chief of Boston Children's Division of Genetics, and his colleagues are studying the genetic causes of microcephaly. Meet one family touched by Dr. Walsh's work.

    Help for kids dealing with the stress of an illness
    The Behavioral Medicine Clinic at Boston Children's helps kids and families deal with anxiety, sadness and fears about their illness, medical and surgical procedures and long-term care. Call 617-355-6688 to learn more.

    Coping and support 

    When your child has a serious condition like microcephaly, your family is dealing with many different concerns and worries. Not only are you focused on meeting all of your child's medical needs; you are also grappling with a significant emotional and psychological toll that affects every member of your family.

    In addition to the clinical information offered on this page, Boston Children's Hospital has several other resources designed to give your family comfort, support and guidance. 

    Patient and family resources at Boston Children's

    • Boston Children's Center for Families is dedicated to helping families locate the information and resources they need to better understand their child's particular condition and take part in their care. All patients, families and health professionals are welcome to use the center's services at no extra cost. The Center for Families is open Monday through Friday from 8 a.m. to 7 p.m., and on Saturdays from 9 a.m. to 1 p.m. Please call 617-355-6279 for more information.
    • The hospital's Complex Care Services provides care for children with complex medical conditions in both inpatient and outpatient settings. CCS partners with the child's family, primary care physician and treatment team specialists to ensure comprehensive, coordinated and centralized medical care. Please call 617-355-6162 for more information.
    • Boston Children's Behavioral Medicine Clinic helps children who are being treated on an outpatient basis at the hospital—as well as their families—understand and cope with their feelings about:
      • being sick
      • facing uncomfortable procedures
      • handling pain
      • taking medication
      • preparing for surgery
      • changes in friendships and family relationships
      • managing school while dealing with an illness
    • The Experience Journal was designed by Boston Children's psychiatrist-in-chief, David DeMaso, MD, and members of his team. This online collection features thoughts, reflections and advice from kids and caregivers about living with a variety of medical conditions, the “befores” and “afters” of surgery and going through many other medical experiences.
    • Boston Children's Psychiatry Consultation Service provides several services, including:
      • short-term therapy for children admitted to one of the hospital's inpatient units
      • parent and sibling consultations
      • teaching healthy coping skills for the whole family
      • educating members of the medical treatment team about the relationship between physical illness and psychological distress
    • Boston Children's Department of Psychiatry offers a free booklet, “Helping Your Child with Medical Experiences: A Practical Parent Guide.” (Adobe Acrobat required to view and download) Topics in the booklet include:
      • talking to your child about her condition
      • preparing for surgery and hospitalization
      • supporting siblings
      • taking care of yourself during your child's illness
      • adjusting to life after treatment
    • The Boston Children's chaplaincy is a source of spiritual support for parents and family members. Our program includes nearly a dozen clergy members—representing Episcopal, Jewish, Lutheran, Muslim, Roman Catholic, Unitarian and United Church of Christ traditions—who will listen to you, pray with you and help you observe your own faith practices during your child's treatment.
    • Boston Children's International Center is a resource for patients and families from countries outside the United States. The center can provide assistance with everything from reviewing medical records to setting up appointments and locating lodging. Contact the center by phone at 01-617-355-5209 or via e-mail at

    General guide for patients and families
    Read our guide to essential information across the hospital.
    Did you know?
    Children's has an Integrative Therapies Team, offering services like therapeutic touch, massage therapy, Reiki and more.


    Helpful links

    Please note that neither Boston Children's Hospital, the Departments of Neurology and Neurosurgery nor the Fetal-Neonatal Neurology Program at Boston Children's  unreservedly endorses all of the information found at the sites listed below. These links are provided as a resource.

    Did you know?
    You can keep family and friends up to date during your child's treatment by creating a free Children's Carepage.
  • Research & Innovation

    At Children’s Hospital Boston, our care is informed by our research, and our discoveries in the laboratory strengthen the care we provide at each child's bedside. Children’s scientific research program is one of the largest and most active of any pediatric hospital in the world.

    In particular, our neurology and neurosurgery researchers are yielding crucial insights into the causes and development of brain disorders, paving the way for the promising new treatments. Learn more about ongoing research efforts in Children's Neuroscience Program. 

    Tracking genetic clues in microcephaly
    Christopher Walsh, MD, PhD, chief of Children’s Division of Genetics, and his colleagues are studying the genetic causes of microcephaly. Throughout the past decade, Walsh and his team have followed more than 200 families with the genetic form of the disease. This research has led to the identification of several new genes involved in the onset of microcephaly.

    Meet one family touched by Dr. Walsh’s work.

    Clinical trials

    Children’s is known for pioneering some of the most effective diagnostic tools, therapies and preventive approaches in pediatric neurology and neurosurgery. A significant part of our success comes from our commitment to research—and to advancing the frontiers of pediatric health care by conducting clinical trials.

    Children’s coordinates hundreds of clinical trials at any given time. Clinical trials are studies that may involve:

    • evaluating the effectiveness of a new drug therapy
    • testing a new diagnostic procedure or device
    • examining a new treatment method for a particular condition
    • taking a closer look at the causes and progression of specific diseases 

    Children’s is involved in several multi-site clinical trials and studies focusing on pediatric neurology and neurosurgery, in particular. While children must meet strict criteria in order to be eligible for a clinical trial, your child may be eligible to take part in a study. Before considering this option, you should be sure to:

    • consult with your child’s treating physician and treatment team
    • gather as much information as possible about the specific course of action outlined in the trial
    • do your own research about the latest breakthroughs relating to your child’s condition 

    Taking part in a clinical trial at Children’s is entirely voluntary. Our team will be sure to fully address any questions you may have, and you may remove your child from the medical study at any time. 

  • One Patient's Experience with Microcephaly

    Saving Grace - Microcephaly research at Boston Children's Hospital

    Michelle Pflumm

    Addison Lennon met all her early milestones: she sat up on time, crawled on time and walked on time. At about 4 months, however, she had a seizure, and her parents started to worry. By 9 months, her head appeared small for her age.

    Her neurologist reassured the family that Addison could still be within the lowest 5 percent of the normal range. "We were thinking she was typical," says Kari Lennon, "she would be in that 5 percent."

    At 15 months, however, Addison had another seizure that was a lot more severe. She had been tested for everything. No one could pinpoint the cause of her so-called microcephaly, or small head.

    Kari spent countless hours online in search of answers. "How I could fix Addie? How could I make her better?"

    Reassured that Addison's condition was likely caused by a virus her mother had contracted during pregnancy, the Lennons went on to have three boys, Sam, Jack and Brooks.

    A new brother: Brooks

    Shortly after his arrival, the Lennons knew that Brooks had the same disease as his sister. His head was small and as he grew, he too fell below the normal range. Could there be a genetic cause?

    Kari remembered, from one of her late-night Internet searches, a clinic at Boston Children's Hospital that specialized in hereditary forms of microcephaly. The clinic team, led by Christopher Walsh, MD, PhD, and which included Edward Gilmore, MD, examined the children. Addison and Brooks did not have any known heritable brain disease.

    "Ed and I looked at each other and said, 'maybe these children have Microcephaly with Seizures,'" recalls Walsh.

    Discovered two years earlier by the Walsh team, Microcephaly with Seizures, or MCSZ, is an extremely unusual form of microcephaly in which the brain is of smaller size but is otherwise structurally normal. People with MCSZ have seizures, but typically many more than Addison and Brooks were experiencing. The team therefore suspected that the children had a mild form of MCSZ. The disease, however, had never been seen outside of the Middle East.

    Undeterred, the team sequenced the children's PNKP gene, the critical gene altered in MCSZ. Both Addison and Brooks had mutations, in both copies of the gene. But one of these mutations had not been seen before, and since it didn't wipe out the function of the gene, the team simply could not be sure that Addison and Brooks had MCSZ.

    The phone call

    Brooks's condition worsened. His seizures were uncontrolled. He was in intensive care every other week. And in the chaos, the Lennons learned that they were expecting another child.

    The Lennons found themselves in a Catch-22. To knowingly bring another child into the world with this genetic condition was unthinkable to them. However, they would not terminate the pregnancy unless they were sure that their future child would have the disease.

    Kari's obstetrician urged the family to reach out one more time to the Walsh team. Perhaps they had identified the cause of their children's microcephaly. "My husband sent an email from the car after we meet with her," Kari recalls. "We heard back from Brenda Barry with the Walsh Lab the next morning asking to speak with us that evening as they did have news to share with us."

    Just weeks before, the team had completed biochemical studies on cells derived from Addison and Brooks, and they now had evidence confirming that the two had MCSZ. Eleven weeks into Kari's pregnancy, the growing fetus was tested and found to be free of the MCSZ mutations its siblings had.

    The Lennons' MCSZ, so rare, could only be detected by studying large families with shared ancestry on the other side of the world. One of the two MCSZ mutations that Addison and Brooks each carried had been previously identified in the Walsh lab's studies of Middle Eastern families.

    "We never would have found this gene in the U.S.," says Walsh. "We needed to go over to the Middle East to make a difference here."

    Amazing Grace

    The day the Lennons' new baby was born, they sent an email to the Boston Children's clinic, announcing that she would be named Grace Gilmore, in part for the neurologist on the Walsh team, and expressing their gratitude for a healthy baby.

    "I cannot remember a better day since I became a doctor," says Walsh. "For a geneticist, this is as good as it gets."

    And Kari Lennon, knowing what is behind her children's condition, can finally sleep at night. "We are so lucky," she says. "They have just given us the biggest gifts in the world. A diagnosis for Addison and Brooks and a baby that is healthy."

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