Microcephaly is a neurodevelopmental disorder in which the circumference of the head is more than two standard deviations smaller than average for the person's age and sex. Microcephaly may be congenital or it may develop in the first few years of life. The disorder may stem from a wide variety of conditions that cause abnormal growth of the brain, or from syndromes associated with chromosomal abnormalities. Two copies of a loss-of-function mutation in one of the microcephalin genes causes primary microcephaly.
In general, life expectancy for individuals with microcephaly is reduced and the prognosis for normal brain function is poor. The prognosis varies depending on the presence of associated abnormalities.
Infants with microcephaly are born with either a normal or reduced head size. Subsequently the head fails to grow while the face continues to develop at a normal rate, producing a child with a small head and a receding forehead, and a loose, often wrinkled scalp. As the child grows older, the smallness of the skull becomes more obvious, although the entire body also is often underweight and dwarfed. Development of motor functions and speech may be delayed. Hyperactivity and mental retardation are common occurrences, although the degree of each varies. Convulsions may also occur. Motor ability varies, ranging from clumsiness in some to spastic quadriplegia in others.
Generally there is no specific treatment for microcephaly. Treatment is symptomatic and supportive.
Microcephalics are known as "chuas" or "rat people" in Pakistan for appearance of sloping forehead and narrow face.
Numerous superstitions revolve around microcephalics in the country, ranging from being condemned as outcastes and institutionally shunned to having divine powers attributed to them. Local myths concerning their origins involve infertile women who practice religious rituals in order to facilitate childbirth, and local religious clergies take the health of the firstborn as a price, cursing them into being a "chua". That child has to be given back to the shrine where it would be raised, and live, as an acolyte. Should she fail to do so, all future children will be born chuas as well. Other Pakistanis believe that priests, chua-masters, or perhaps even parents, purposefully deform healthy infants by placing pots or metal clamps on the heads of healthy infants and so retard the growth of the brain.