Microcephaly Page

I have searched the internet for the term "microcephaly" and this is what I have come up with.

DESCRIPTION: Microcephaly is a rare, neurological disorder in which the circumference of the head is smaller than the average for the age and gender of the infant or child. Microcephaly may be congenital (present at birth) 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, and is often a symptom of syndromes associated with chromosomal abnormalities. Infants with microcephaly are born with either a normal or reduced head size. As the child grows older, the smallness of the skull becomes more obvious, although the entire body also is often underweight or small. 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 to spastic quadriplegia.

TREATMENT: Generally there is no specific treatment for microcephaly. Treatment is symptomatic and supportive. A serious attempt should be made to identify associated congential anomalies and to determine a specific cause of the disorder. A referral to a genetic specialist can help determine the cause of your child's microcephaly.

PROGNOSIS: In general, life expectancy for individuals with microcephaly is low and the prognosis for normal brain function is poor. The prognosis varies depending on the presence of associated abnormalities.

NOTE: The degree of damage is HIGHLY VARIABLE. Developmental delays can be severe or slight. Your child MUST BE TESTED in order to determine the degree of deveopmental delay he/she might have.

RESEARCH: Medical research conducts and supports a wide range of studies that explore the complex mechanisms of normal brain development. The knowledge gained from these fundamental studies provides the foundation for understanding how this process can go awry and, thus, offers hope for new means to treat and prevent developmental brain disorders, including microcephaly.

Another site said this...

Microcephaly is defined by a head circumference, as measured around the glabella and occipital protuberance, that is more than 2 standard deviations below the mean for age, sex, race, and gestation. Microcephaly is always caused by microencephaly, a small brain, and the two terms are used interchangeably. In the normally shaped head the occipital frontal circumference is an index of cranial volume. Where the head shape is abnormal, as in certain forms of craniosynostosis, the head circumference is not a valid index of cranial volume and does not correlate with microcephaly.

Microcephaly has generally been equated with mental retardation. However, not all children with head circumference less than 2 standard deviations are mentally retarded. A child with "measurement microcephaly" who is of small stature because of familial factors or growth retardation secondary to malabsorption or cardiac disease is, therefore, not in the same category from the standpoint of CNS function as one with microcephaly resulting from organic brain disease. Twenty-five percent of hypopituitary dwarfs with normal IQ were microcephalic. Normal intelligence was also measured in 40% of those infants after exposure to the atomic bombs as fetuses.

An abnormally small brain either is caused by anomalous development during the first 7 months of gestation (primary microcephaly), or is the result of an insult incurred during the last 2 months of gestation or during the perinatal period (secondary microcephaly). It can also be classified as congenital or acquired.

Congenital microcephaly may follow intrauterine infections with rubella, CMV, Toxoplamosis. Congenital microcephaly is also a part of many chromosomal abnormalities and other syndromes. Most common conditions associated with primary microcephaly include:

· Gross chromosomal abnormalities
· Trisomy 18

· Trisomy 13
· Wolf-Hirschhorn syndrome
· Cri du Chat syndrome
· Partial deletion of long arm of 13
· Contigous gene syndromes
· Miller-Dieker syndrome
· Langer-Giedion syndrome
· Prader-Willi syndrome
· Aniridia-Wilms tumour syndrome
· Autosomal recessive disorder
· Johanson-Blizzard syndrome
· Seckel syndrome
· Smith-Lemli-OPitz syndrome
· Coffin-Siris syndrome (?)
· Rubinstein-Taybi syndrome
· Maternal PKU
Congenital (primary) microcephaly can also result from a variety of insults that cause anomalies of induction and migration. The condition may be autosomal recessive or associated with chromosomal disorders. The infants are abnormal at birth. They not only have a small head but also have characteristic facial and cranial configurations. Their rounded heads, with small or absent anterior fontanel and recessed or sloped forehead indicative of the shallow anterior cranial fossa, readily identify them as infants with severe morphologic cerebral abnormalities. Some demonstrate immediate signs of neurologic dysfunction such as hypotonicity, hypertonicity, or an abnormal cry, whereas others function surprisingly normally for the first few months of life.
Acquired microcephaly may result from perinatal infections such as herpes simplex, from intrapartum or neonatal hypoxic-ischemic insults, and from metabolic causes, including aminoacidurias and hypothyroidism. In these patients, head circumference is normal at birth, but the rate of brain growth is impaired, with resultant microcephaly.
Anencephaly is a variable malformation of brain development in which the cerebral hemispheres are virtually absent and brain stem structures are variably affected. There is a variable inherited component to this disorder. Antenatal diagnosis is aided by finding of elevated alpha-fetoprotein levels in amniocentesis. Furthurmore, the accompanying absence of bony structures of the skull leads to a characteristic froglike appearance on antenatal ultrasound. There is no possibility for long-term survival in these patients.
Lissencephaly is near-total or total absence of cerebral convolutions (agyria), reminiscent of fetal brain during the second to fourth months' gestation. This is a feature of many syndromes including Mueller-Dieker syndrome. The clinical picture includes microcephaly, hypotonia, and seizures, most commonly infantile spasms.
Pachygyria is characterized by relatively few broad gyri and shallow sulci. It appears to represent a developmental arrest of maturation and cell migration at a slightly later stage, with the result being abnormally broad, flat cerebral convolutions with a thick cerebral cortex. The ventricular system is slightly enlarged, and other anomalies, such as areas of gray matter heterotopia, are usually present in these types of malformed brains.
Polymicrogyria is more often associated with hydrocephalus than microcephaly and is characterized by either localized or generalized excessive and small cerebral convolutions. The clinical picture is one of mental retardation and spaticity, or hypotonia with active deep tendon reflexes ("atonic cerebral palsy").
Each infant with microcephaly deserves a complete evaluation and determinations of the cause if at all possible. This should include serologic studies for TORCH agent infections, CT scan, and amino acid screening. The presence of other somatic abnormalities may lead to chromosomal evaluation. There is no treatment for microcephaly.