congenital malformation of the cerebrum microcephaly http://purl.bioontology.org/ontology/MEDDRA/10027534 http://purl.bioontology.org/ontology/MESH/D008831 http://purl.obolibrary.org/obo/DOID_10907 http://purl.obolibrary.org/obo/HP_0000252 http://purl.obolibrary.org/obo/NCIT_C85874 https://en.wikipedia.org/wiki/Microcephaly https://www.wikidata.org/wiki/Q431643 A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. Head circumference below 2 standard deviations below the mean for age and gender. Head circumference is measured from just above the glabella (the most prominent point on the frontal bone above the root of the nose) to the most posterior prominent point of the occipital bone using a tape measure. Some standard charts are organized by centiles, others by standard deviations. It is important to add an indication of how far below the normal standard the head circumference is if an accurate assessment of this can be made. Microcephaly is an absolute term. The term relative microcephaly can be used when the head size centile is less than the centile for height, for example, head size at the 3rd centile with height at the 75% for age and sex. On prenatal ultrasound, microcephaly is diagnosed if the head circumference or the biparietal diameter is more than three standard deviations below the mean. Q02