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Microcephaly

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Skull of a newborn Microcephaly Ultrasound, normal fetus - ventricles of brain

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Microcephaly

Definition:

Microcephaly describes a head size (measured as the distance around the top of the head) significantly below normal for a person's age and sex, based on standardized charts.

Considerations:

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Microcephaly most often occurs because of failure of the brain to grow at a normal rate. Skull growth is determined by brain expansion, which takes place during the normal growth of the brain during pregnancy and infancy.

Conditions that affect brain growth can cause microcephaly, including infections, genetic disorders, and severe malnutrition.

Common Causes:

Primary Causes:

• Down's syndrome
• cri du chat syndrome
• Seckel's syndrome
• Rubinstein-Taybi syndrome
• trisomy 13
• trisomy 18
• Smith-Lemli-Opitz syndrome
• Cornelia de Lange syndrome

Secondary Causes:

• uncontrolled maternal phenylketonuria (PKU)
• methylmercury poisoning
• congenital rubella
• congenital toxoplasmosis
• congenital CMV
• maternal drug use
• malnutrition

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