Moreover, an association has been established between common genetic variants within known microcephaly genes (such as MCPH1 and CDK5RAP2) and normal variation in brain structure as measured with magnetic resonance imaging (MRI)‍—‌i.e., primarily brain cortical surface area and total brain volume.The spread of Aedes mosquito-borne Zika virus has been implicated in increasing levels of congenital microcephaly by the International Society for Infectious Diseases and the US Centers for Disease Control and Prevention. Zika can spread from a pregnant woman to her fetus. This can result in other severe brain malformations and birth defects. A study published in The New England Journal of Medicine has documented a case in which they found evidence of the Zika virus in the brain of a fetus that displayed the morphology of microcephaly. Microlissencephaly
Microlissencephaly is microcephaly combined with lissencephaly (smooth brain surface due to absent sulci and gyri). Most cases of microlissencephaly are described in consanguineous families, suggesting an autosomal recessive inheritance. Historical causes of microcephaly
After the dropping of atomic bombs "Little Boy" on Hiroshima and "Fat Man" on Nagasaki, several women close to ground zero who had been pregnant at the time gave birth to children with microcephaly. Microcephaly was present in 7 children from a group of 11 pregnant women at 11–17 weeks of gestation who survived the blast at less than 1.2 km (0.75 mi) from ground zero.
Childhood absence epilepsy (CAE), is one of the most frequent pediatric epilepsy syndromes. CAE is an idiopathic generalized epilepsy that occurs in otherwise normal children. The only seizure type at the time of diagnosis is the typical absence seizure. CAE is a well-known pediatric epilepsy syndrome affecting 10–17% of all children with epilepsy. It was previously known as pyknolepsy. The word pyknolepsy originates from the Greek piknoz (picnós), which means recurrent or grouped. The usual age of onset of CAE is between 4 and 10 years, with peak between 5 and 7 years.The typical absence seizure has a sudden onset of altered awareness and ends also abruptly. Electroencephalogram demonstrate characteristic "typical 3Hz spike-wave" generalized rhythmic discharges that begin and end abruptly. Prognosis is generally good with fair rates of response to treatment and with most patients growing out of their absencese. However, learning difficulties and seizure occurrence rates remain higher than the general population even after several years. When typical absence seizures start the age of 8– 9 years old when the absence seizures are infrequent or when the absence seizures are observed in a patient that had experienced a generalized tonic-clonic seizure, a diagnosis of juvenile absence epilepsy should be considered. Signs and symptoms
CAE is characterized by the presence of absence seizures. The absence seizures are usually brief (about 4 to 30 seconds) but occur frequently, usually around a dozen per day but sometimes even hundreds of times per day.