Send us a Message

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


The Human Phenotype Ontology (HPO) is downloaded weekly from The file downloaded is considered the "last stable build" available for the ontology. For more about the HPO, view their website at

Term:Thickened nuchal skin fold
go back to main search page
Accession:HP:0000474 term browser browse the term
Definition:A thickening of the skin thickness in the posterior aspect of the fetal neck. A nuchal fold (NF) measurement is obtained in a transverse section of the fetal head at the level of the cavum septum pellucidum and thalami, angled posteriorly to include the cerebellum. The measurement is taken from the outer edge of the occiput bone to the outer skin limit directly in the midline. An NF measurement greater than 5 mm at 14 to 17+6 weeks of gestation, or 6 mm at 18 to 28 weeks has been associated with a markedly increased risk for Down syndrome.
Comment:The measurement of nuchal fold (NF) thickness during the second trimester is considered to be one of the most sensitive and specific isolated ultrasound marker for the identification of suspected cases of trisomy 21. Thick NF may also be seen in other aneuploidies as well as Turner's syndrome, Noonan's syndrome, Roberts syndrome, Zellweger syndrome and with congenital heart disease and with pathogenic CNVs. A thickened nuchal fold should be distinguished from cystic hygroma, in which the skin in this area has fluid-filled loculations. A thickened nuchal fold should not be confused with nuchal translucency, which is a specific measurement of fluid in the posterior aspect of the neck at 11 to 14 weeks gestation (see practice guidelines at
Synonyms:exact_synonym: Excess nuchal skin;   Increased nuchal fold;   Increased nuchal fold thickness;   Thick nuchal fold;   Thickened nuchal skin;   Thickened skin folds of neck;   Thickened skin over the neck
 alt_id: HP:0000477
 xref: UMLS:C1836940

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 prenatal development or birth 0
        Fetal anomaly 0
          Abnormal fetal morphology 0
            Fetal ultrasound soft marker 0
              Thickened nuchal skin fold 0
paths to the root