| Microcephaly is a medical condition in
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| | older, the smallness of the skull becomes
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| which the circumference of the head is
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| | more obvious, although the entire body
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| smaller than normal because the brain has
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| | also is often underweight and dwarfed.
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| not developed properly or has stopped
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| | Development of motor functions and speech
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| growing. Microcephaly can be present at
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| | may be delayed. Hyperactivity and mental
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| birth or it may develop in the first few
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| | retardation are common occurrences,
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| years of life. It is most often caused
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| | although the degree of each varies.
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| by genetic abnormalities that interfere
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| | Convulsions may also occur. Motor ability
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| with the growth of the cerebral cortex
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| | varies, ranging from clumsiness in some
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| during the early months of fetal
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| | to spastic quadriplegia in others.
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| development. It is associated with
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| | Causes of Microcephaly
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| Down's syndrome, chromosomal syndromes,
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| | Microcephaly can occur alone or in
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| and neurometabolic syndromes. Babies may
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| | association with other health problems,
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| also be born with microcephaly if, during
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| | and may occur from inheritance of an
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| pregnancy, their mother abused drugs or
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| | autosomal recessive, or rarely, an
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| alcohol, became infected with a
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| | autosomal dominant gene. Acquired
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| cytomegalovirus, rubella (German
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| | microcephaly may occur after birth due to
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| measles), or vermicelli (chicken pox)
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| | various brain injuries such as lack of
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| virus, was exposed to certain toxic
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| | oxygen or infection.
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| chemicals, or had untreated
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| | Microcephaly may be inherited but the
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| phenylketonuria (PKU). Babies born with
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| | gene is considered to be extremely rare.
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| microcephaly will have a smaller than
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| | In the general population, microcephaly
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| normal head that will fail to grow as
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| | due to genetic factors occurs in 1 in
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| they progress through infancy.
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| | 30,000 to 50,000 live births, and in 1
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| In many cases, microcephaly may not be
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| | per 10,000 births due to other causes. In
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| evident by ultrasound until the third
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| | some populations, frequency may be as
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| trimester, and, therefore, may not be
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| | high as 1 in 2,000 births.
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| seen on ultrasounds performed earlier in
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| | Microcephaly can also be caused if the
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| pregnancy. The diagnosis of microcephaly
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| | mother has an infection while pregnant or
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| may be made at birth or later in infancy.
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| | if she is exposed to harmful substances
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| The baby's head circumference is much
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| | during early pregnancy, such as x-rays (a
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| smaller than normal. During the physical
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| | type of energy) or chemicals. Another
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| examination, the physician obtains a
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| | cause of microcephaly is if the bones of
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| complete prenatal and birth history of
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| | the skull come together too early. For
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| the child. In older babies and children,
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| | genetic (inherited) causes of
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| the physician may also ask if there is a
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| | microcephaly, see the next section.
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| family history of microcephaly or other
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| | Microcephaly is either caused by exposure
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| medical problems. The physician will also
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| | to harmful substances during the fetal
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| ask about developmental milestones since
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| | development, or it may be associated with
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| microcephaly can be associated with other
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| | genetic problems or syndromes that may
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| problems, such as mental retardation.
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| | have a tendency to run in families.
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| Infants with microcephaly are born with
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| | Microcephaly most often occurs because of
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| either a normal or reduced head size.
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| | failure of the brain to grow at a normal
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| Subsequently the head fails to grow while
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| | rate. Skull growth is determined by brain
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| the face continues to develop at a normal
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| | expansion, which takes place during the
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| rate, producing a child with a small head
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| | normal growth of the brain during
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| and a receding forehead, and a loose,
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| | pregnancy and infancy.
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| often wrinkled scalp. As the child grows
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