Microcephaly is characterized by a development of the cranial perimeter, at birth, less than normal. Infants born with microcephaly usually have a small brain size, which therefore cannot develop properly. (1)

The prevalence of the disease (number of cases in a given population at a given time) is, to this day, still unknown. In addition, it has been shown that the disease is present, in greater frequency, in Asia and the Middle East with an incidence of 1 / 1 per year. (000)

Microcephaly is a condition that is defined by the size of the baby’s head that is smaller than normal. During pregnancy, the child’s head grows normally thanks to the progressive development of the brain. This disease can then develop during pregnancy, during abnormal development of the child’s brain, or at birth, when its development suddenly stops. Microcephaly can be a consequence in its own right, without the child presenting other abnormalities or else be associated with other deficiencies visible at birth. (1)

There is a severe form of the disease. This serious form appears as a result of abnormal brain development during pregnancy or at birth.

Microcephaly can therefore be present at the birth of the child or develop in the first months after childbirth. This disease is often the result of genetic abnormalities interfering with the growth of the cerebral cortex during the first months of fetal development. This pathology can also be the consequence of abuse of drugs or alcohol in the mother, during her pregnancy. Maternal infections with cytomegalovirus, rubella, chickenpox, etc. can also be the source of the disease.

In the case of maternal infection with Zika virus, spread of the virus is also visible in the tissues of the child leading to brain death. In this context, kidney damage is often associated with Zika virus infection.

The consequences of the disease depend on the severity of it. Indeed, children developing microcephaly can present impairments in cognitive development, delays in motor functions, language difficulties, short build, hyperactivity, epileptic seizures, incoordination or even d ‘ other neurological abnormalities. (2)

Microcephaly is characterized by a head size that is smaller than normal. This anomaly is the consequence of reduced brain development during the fetal period or after childbirth.

Infants born with microcephaly can have a number of clinical manifestations. These depend directly on the severity of the disease and include: (1)

– epileptic seizures;

– delays in the child’s mental development, in speaking, in walking, etc. ;

– intellectual disabilities (reduced learning capacity and delay in vital functions);

– problems of incoordination;

– swallowing difficulties;

– hearing loss;

– eye problems.

These different symptoms can range from mild to severe throughout the life of the subject.

Microcephaly is usually the result of delayed development of a child’s brain, causing the head circumference to be smaller than normal. From the point of view where brain development is effective during pregnancy and childhood, microcephaly can develop during these two periods of life.

Scientists have put forward different origins of the disease. Among these are certain infections during pregnancy, genetic abnormalities or even malnutrition.

In addition, some of the following genetic diseases are also involved in the development of microcephaly:

– Cornelia de Lange syndrome;

– the cry of the cat syndrome;

– Down’s syndrome;

– Rubinstein – Taybi syndrome;

– Seckel’s syndrome;

– Smith -Lemli- Opitz syndrome;

– trisomy 18;

– Down’s syndrome.

Other origins of the disease include: (3)

– uncontrolled phenylketonuria (PKU) in the mother (consequence of an abnormality of phenylalanine hydroxylase (PAH), increasing the production of plasma phenylalanine and having a toxic effect on the brain);

– methylmercury poisoning;

– congenital rubella;

– congenital toxoplasmosis;

– infection with congenital cytomegalovirus (CMV);

– the use of certain medicines during pregnancy, in particular alcohol and phenytoin.

Maternal infection with Zika virus has also been shown to be the cause of the development of microcephaly in children. (1)

The risk factors associated with microcephaly therefore include a set of maternal infections, genetic abnormalities whether or not hereditary, uncontrolled phenylketonuria in the mother, exposure to certain chemicals (such as methylmercury), etc.

The diagnosis of microcephaly can be made during pregnancy or right after the birth of the child.

During pregnancy, ultrasound examinations can diagnose the possible presence of the disease. This test is generally performed during the 2nd trimester of pregnancy or even at the start of the 3rd trimeter.

Following the birth of the baby, medical devices measure the average size of the baby’s head circumference (head circumference). The measurement obtained is then compared to the means of the population as a function of age and sex. This post-birth test is usually done at least 24 hours after childbirth. This period makes it possible to ensure the correct re-formation of the skull, compressed during childbirth.

If the presence of microcephaly is suspected, other additional examinations are possible to confirm or not the diagnosis. These include, in particular, the scanner, MRI (Magnetic Resonance Imaging), etc.

The treatment of the disease extends over the entire life of the subject. Currently, no curative drug is developed.

Since the severity of the disease is different from one child to another, babies whose form is benign will have no symptoms other than a narrowed head circumference. These cases of the disease will therefore only be closely monitored during the development of the child.

In the case of the more severe forms of the disease, the children, this time, need treatments allowing to fight against the peripheral problems. Therapeutic means exist to improve and maximize the intellectual and physical capacities of these children. Medicines to prevent seizures and other clinical manifestations may also be prescribed. (1)

The disease prognosis is generally good but depends heavily on the severity of the disease. (4)