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Microcephaly: Symptoms, Causes and General Overview

Author: Thomas C. Weiss

Contact : Disabled World

Published: 2016-01-14 - (Updated: 2020-03-27)


Microcephaly is a form of rare, neurological condition in which an infant's head is notably smaller than the heads of other children of the same gender and age.

Key Points:

Main Digest

Although Microcephaly is classified as a neurodevelopmental disorder, no uniformity exists in its definition. It is usually defined as a head circumference more than 2 standard deviations below the mean for age and sex - some academics advocate defining it as head circumference more than 3 standard deviations. A genetic factor may play a role in causing some cases of microcephaly. Relationships have been found between autism, duplications of chromosomes, and macrocephaly on one side. On the other side, a relationship has been found between schizophrenia, deletions of chromosomes, and microcephaly.

Head circumference greater than two standard deviations below the mean.
Head circumference greater than two standard deviations above the mean.

Microcephaly may be caused by a number of environmental and genetic factors. Children with the condition often have developmental issues. In general, there is no treatment for microcephaly, although early intervention with supportive therapies such as speech and occupational therapies might help to enhance a child's development while improving their quality of life.

Microcephaly Symptoms

The main sign of microcephaly is a head size significantly smaller than that of children of the same gender and age. Head size is measured as the distance around the top of the child's head, or circumference. Using standardized growth charts, the measurement is compared with the measurements of other children in percentiles.

Some children simply have small heads with measurements falling as low as the first percentile. In children with microcephaly, head size measures notably below average – potentially even below the first percentile for a child's gender and age. A child with more severe microcephaly might also have a backward-sloping forehead.


Microcephaly is usually the result of non-standard brain development, which may happen in the womb or during infancy. The condition may be genetic. Additional causes of microcephaly may include the following:


Some children with microcephaly experience average intelligence and development, despite the fact their heads will always be small for both their gender and age. Yet depending on the cause and severity of the microcephaly, complications might include the following:

Tests and Diagnosis

To determine whether or not a child has microcephaly, a doctor most likely will take a thorough prenatal, pursue birth and family history, as well as perform a physical examination. The doctor will measure the circumference of the child's head, compare it with a growth chart and re-measure and plot the growth at visits in the future. Parents' head sizes might also be measured to determine whether or not small heads run in the family. In some instances, especially if a child's development is delayed, a doctor may request tests such as an MRI, CT scan, or blood tests to help determine the underlying cause of the delay.


With the exception of surgery for craniosynostosis, there is generally no form of treatment that will enlarge a child's head, or reverse complications of microcephaly. Treatment concentrates on ways to manage the child's condition. Early childhood intervention programs include physical, occupational and speech therapies which may help the child to strengthen their abilities. A doctor may recommend medication for certain complications of microcephaly, such as hyperactivity or seizures.

Coping with Microcephaly

Upon learning a child has microcephaly, the emotions of parents may include fear, anger, sorrow, worry or guilt. Parents might not know what to expect and may worry about their child's future. The best means of coping involves information and support.

Learning your child has microcephaly can raise questions concerning future pregnancies. Work with a doctor to determine the cause of microcephaly in your child. If the cause is genetic, you might wish to consult a genetics counselor about the risks of microcephaly in future pregnancies.

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