Microcephaly

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 themicrocephalin 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.

Causes                           

Microcephaly is a type of cephalic disorder.

A genetic factor may play a role in causing some cases of microcephaly. Relations have been found between autism, duplications of chromosomes and macrocephaly on one side. On the other side a relation has been found between schizophrenia, deletions of chromosomes and microcephaly

Microencephaly

"Microcephaly" means "small head". "Microencephaly" means "small brain". Because the size of the head is mostly determined by the size of the brain, microencephaly is implied when discussing microcephaly

Other

Microcephaly can also be associated with other conditions that are only indirectly associated with the nervous system:

• alcoholism (which can result in the fetal alcohol syndrome disability)
• diabetes
• varicella zoster virus (Chickenpox)
• rubella (German measles)
• CMV (human cytomegaovirus)
• radiation

After the dropping of atomic bombs on Hiroshima and Nagasaki, several women close to ground zero who had been pregnant at the time gave birth to children with microcephaly. A total of seven of the in utero children at Hiroshima were affected.Microcephaly prevalence was 7 out of a group of 11 pregnant women who held the distinction of surviving the blast at an distance of ≈1 km from ground zero. Due to their proximity to the bomb, the pregnant women's in utero children received a biologically significant radiation dosage that was relatively high due to the massive neutron output of the lower explosive-yielding Little Boy.Microcephaly is the only proven malformation, or congenital abnormality, found in the children of Hiroshima and Nagasaki

Read More

Neurological disorder.

A neurological disorder is any disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain and altered levels of consciousness.There are many recognized neurological disorders, some relatively common, but many rare. They may be assessed by neurological examination, and studied and treated within the specialities ofneurology and clinical neuropsychology.

Interventions for neurological disorders include preventative measures, lifestyle changes, physiotherapy or other therapy,neurorehabilitation, pain management, medication, or operations performed by neurosurgeons. The World Health Organization estimated in 2006 that neurological disorders and their sequelae (direct consequences) affect as many as one billion people worldwide, and identified health inequalities and social stigma/discrimination as major factors contributing to the associated disability and suffering.

Causes

Part of the causal chain leading to Alzheimer's disease.

Although the brain and spinal cord are surrounded by tough membranes, enclosed in the bones of the skull and spinal vertebrae, and chemically isolated by the so-called blood-brain barrier, they are very susceptible if compromised. Nerves tend to lie deep under the skin but can still become exposed to damage. Individual neurons, and the neural networks and nerves into which they form, are susceptible to electrochemical and structural disruption. Neuroregeneration may occur in the peripheral nervous system and thus overcome or work around injuries to some extent, it is thought to be rare in the brain and spinal cord.

The specific causes of neurological problems vary, but can include genetic disorders, congenital abnormalities or disorders, infections, lifestyle orenvironmental health problems including malnutrition, and brain injury, spinal cord injury or nerve injury. The problem may start in another body system that interacts with the nervous system. For example, cerebrovascular disorders involve brain injury due to problems with the blood vessels(cardiovascular system) supplying the brain; autoimmune disorders involve damage caused by the body's own immune system; lysosomal storage diseases such as Niemann-Pick disease can lead to neurological deterioration.

In a substantial minority of cases of neurological symptoms, no neural cause can be identified using current testing procedures, and such "idiopathic" conditions can invite different theories about what is occurring.

Read More