diff --git a/src/ontology/mp-edit.owl b/src/ontology/mp-edit.owl
index 3e1a134d..bef3756f 100644
--- a/src/ontology/mp-edit.owl
+++ b/src/ontology/mp-edit.owl
@@ -14383,6 +14383,7 @@ Declaration(Class(<http://purl.obolibrary.org/obo/MP_0031527>))
 Declaration(Class(<http://purl.obolibrary.org/obo/MP_0031528>))
 Declaration(Class(<http://purl.obolibrary.org/obo/MP_0031529>))
 Declaration(Class(<http://purl.obolibrary.org/obo/MP_0031530>))
+Declaration(Class(<http://purl.obolibrary.org/obo/MP_0031531>))
 Declaration(Class(<http://purl.obolibrary.org/obo/MP_3000001>))
 Declaration(Class(<http://purl.obolibrary.org/obo/MP_3000002>))
 Declaration(Class(<http://purl.obolibrary.org/obo/MP_3000003>))
@@ -106315,7 +106316,7 @@ AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasOBONamespac
 AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#id> <http://purl.obolibrary.org/obo/MP_0010533> "MP:0010533")
 AnnotationAssertion(rdfs:label <http://purl.obolibrary.org/obo/MP_0010533> "atrioventricular node hypoplasia")
 EquivalentClasses(<http://purl.obolibrary.org/obo/MP_0010533> ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/BFO_0000051> ObjectIntersectionOf(<http://purl.obolibrary.org/obo/PATO_0000645> ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/RO_0000052> <http://purl.obolibrary.org/obo/UBERON_0002352>) ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/RO_0002573> <http://purl.obolibrary.org/obo/PATO_0000460>))))
-SubClassOf(<http://purl.obolibrary.org/obo/MP_0010533> <http://purl.obolibrary.org/obo/MP_0004114>)
+SubClassOf(<http://purl.obolibrary.org/obo/MP_0010533> <http://purl.obolibrary.org/obo/MP_0031531>)
 
 # Class: <http://purl.obolibrary.org/obo/MP_0010534> (calcified myocardium)
 
@@ -185979,6 +185980,22 @@ AnnotationAssertion(rdfs:label <http://purl.obolibrary.org/obo/MP_0031530> "abno
 EquivalentClasses(<http://purl.obolibrary.org/obo/MP_0031530> ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/BFO_0000051> ObjectIntersectionOf(<http://purl.obolibrary.org/obo/PATO_0000052> ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/RO_0000052> <http://purl.obolibrary.org/obo/UBERON_0002082>) ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/RO_0002573> <http://purl.obolibrary.org/obo/PATO_0000460>))))
 SubClassOf(<http://purl.obolibrary.org/obo/MP_0031530> <http://purl.obolibrary.org/obo/MP_0005294>)
 
+# Class: <http://purl.obolibrary.org/obo/MP_0031531> (decreased atrioventricular node size)
+
+AnnotationAssertion(Annotation(<http://www.geneontology.org/formats/oboInOwl#hasDbXref> "https://orcid.org/0000-0002-6490-7723") <http://purl.obolibrary.org/obo/IAO_0000115> <http://purl.obolibrary.org/obo/MP_0031531> "less than average size of the atrioventricular node compared to controls")
+AnnotationAssertion(<http://purl.org/dc/elements/1.1/date> <http://purl.obolibrary.org/obo/MP_0031531> "2023-12-12T13:44:32Z"^^xsd:dateTime)
+AnnotationAssertion(<http://purl.org/dc/terms/contributor> <http://purl.obolibrary.org/obo/MP_0031531> <https://orcid.org/0000-0002-6490-7723>)
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasExactSynonym> <http://purl.obolibrary.org/obo/MP_0031531> "decreased AV nodal size")
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasExactSynonym> <http://purl.obolibrary.org/obo/MP_0031531> "reduced AV nodal size")
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasExactSynonym> <http://purl.obolibrary.org/obo/MP_0031531> "reduced atrioventricular node size")
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasExactSynonym> <http://purl.obolibrary.org/obo/MP_0031531> "small AV node")
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasExactSynonym> <http://purl.obolibrary.org/obo/MP_0031531> "small atrioventricular node")
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#hasOBONamespace> <http://purl.obolibrary.org/obo/MP_0031531> "MPheno.ontology")
+AnnotationAssertion(<http://www.geneontology.org/formats/oboInOwl#id> <http://purl.obolibrary.org/obo/MP_0031531> "MP:0031531")
+AnnotationAssertion(rdfs:label <http://purl.obolibrary.org/obo/MP_0031531> "decreased atrioventricular node size")
+EquivalentClasses(<http://purl.obolibrary.org/obo/MP_0031531> ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/BFO_0000051> ObjectIntersectionOf(<http://purl.obolibrary.org/obo/PATO_0000587> ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/RO_0000052> <http://purl.obolibrary.org/obo/UBERON_0002352>) ObjectSomeValuesFrom(<http://purl.obolibrary.org/obo/RO_0002573> <http://purl.obolibrary.org/obo/PATO_0000460>))))
+SubClassOf(<http://purl.obolibrary.org/obo/MP_0031531> <http://purl.obolibrary.org/obo/MP_0004114>)
+
 # Class: <http://purl.obolibrary.org/obo/MP_3000001> (abnormal gastrula morphology)
 
 AnnotationAssertion(Annotation(<http://www.geneontology.org/formats/oboInOwl#hasDbXref> "http://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-18-week-3-of-development-trilaminar-germ-disk-embryo-formation-and-gastrulation") <http://purl.obolibrary.org/obo/IAO_0000115> <http://purl.obolibrary.org/obo/MP_3000001> "any structural anomaly of the pear shaped trilaminar embryonic stage in which the primititve streak elongates, the epiblast cells migrate medially towards the streak, enter the primitive groove and migrate laterally to organize into the intraembryonic mesoderm (epithelio-mesenchymal transition) between the embryonic ectoderm and primitive endoderm; the notochordal process forms and extends, and the disc becomes pear shaped as the notochordal process grows")