Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

HUMAN PHENOTYPE - ANNOTATIONS

The Human Phenotype Ontology (HPO) is downloaded weekly from http://compbio.charite.de/hudson/job/hpo/lastStableBuild/artifact/ontology/release/hp.obo. The file downloaded is considered the "last stable build" available for the ontology. For more about the HPO, view their website at http://www.human-phenotype-ontology.org/.

Term:Microcephaly
go back to main search page
Accession:HP:0000252 term browser browse the term
Definition:Head circumference below 2 standard deviations below the mean for age and gender.
Comment: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. Microcephaly is divided into primary microcephaly, which is present at birth, and secondary microcephaly, which develops postnatally. The crucial difference between these groupings is that primary microcephaly is usually a static developmental anomaly, whereas secondary microcephaly indicates a progressive neurodegenerative condition
Synonyms:exact_synonym: Abnormally small cranium;   Abnormally small skull;   Decreased size of cranium;   Decreased size of skull;   Reduced head circumference;   Small head circumference;   decreased circumference of cranium;   small calvarium;   small cranium
 broad_synonym: Abnormally small head;   Decreased size of head;   small head;   small skull
 alt_id: HP:0001366;   HP:0005485;   HP:0005489;   HP:0005497
 xref: Fyler:4310;   SNOMEDCT_US:271611007;   UMLS:C4551563



show annotations for term's descendants           Sort by:

Term paths to the root
Path 1
Term Annotations click to browse term
  Human phenotype 0
    Phenotypic abnormality 0
      Abnormality of the nervous system 0
        Abnormal nervous system morphology 0
          Morphological central nervous system abnormality 0
            Aplasia/Hypoplasia involving the central nervous system 0
              Aplasia/Hypoplasia of the cerebrum 0
                Microcephaly 0
                  Primary microcephaly 0
                  Secondary microcephaly + 0
Path 2
Term Annotations click to browse term
  Human phenotype 0
    Phenotypic abnormality 0
      Abnormality of the nervous system 0
        Abnormal nervous system morphology 0
          Morphological central nervous system abnormality 0
            Abnormality of brain morphology 0
              Abnormal forebrain morphology 0
                Abnormal cerebral morphology 0
                  Aplasia/Hypoplasia of the cerebrum 0
                    Microcephaly 0
                      Primary microcephaly 0
                      Secondary microcephaly + 0
paths to the root