Microcephaly

Microcephaly is a condition in which head circumference is substantially smaller than expected for age and sex. It can result from impaired brain growth before or after birth and varies widely in its effects.

Head circumference: The measurement around the largest part of the head, used to monitor skull and brain growth. Microcephaly is identified by comparing this measurement with age- and sex-based standards.
Primary microcephaly: Microcephaly present at birth, often caused by genetic disruptions to early brain development. It is a major congenital form in which impaired prenatal brain growth produces the small head.
Growth chart: A graph comparing a person's growth measurements with reference distributions for age and sex. Repeated head-circumference measurements show whether growth follows an expected trajectory.
Intellectual disability: A condition involving significant limitations in intellectual functioning and adaptive behavior beginning during development. It can occur with microcephaly, but head size alone cannot predict cognitive ability.
Occipitofrontal circumference: The distance around the head measured from the forehead to the most prominent part of the back of the skull. This standardized measurement is commonly used to assess head size in suspected microcephaly.
Postnatal microcephaly: Microcephaly that develops after birth when head growth slows or fails to keep pace with age-based expectations. It differs from congenital microcephaly because the growth divergence emerges after birth.
Prenatal ultrasound: An imaging technique that uses sound waves to examine fetal structures during pregnancy. It can identify unusually small fetal head measurements and associated brain abnormalities.
Epilepsy: A neurological disorder characterized by an enduring tendency to have unprovoked seizures. Brain abnormalities associated with microcephaly can increase seizure risk.
Fetal brain development: The prenatal growth and organization of the brain from early neural structures into a functioning organ. Disruptions during this process can limit brain and skull growth before birth.
MCPH1: A gene encoding a protein involved in chromosome regulation and brain development; variants can cause primary microcephaly. Its discovery connected inherited microcephaly with genes regulating neural development.

Linked from 9 pages