Chapter 17

Q00–Q99: Congenital Malformations, Deformations and Chromosomal Abnormalities

Congenital Malformations, Deformations and Chromosomal Abnormalities diagnostic classification updated for 2026.

Chapter Instructions

Excludes2(Not included here. Code separately if applicable.)
  • inborn errors of metabolism (E70-E88)
Internal Codes
  • Q18.3|

    Webbing of neck

  • Q18.4|

    Macrostomia

  • Q18.5|

    Microstomia

  • Q18.6|

    Macrocheilia

  • Q18.7|

    Microcheilia

  • Q18.8|

    Other specified congenital malformations of face and neck

  • Q18.9|

    Congenital malformation of face and neck, unspecified

  • Q20.0|

    Common arterial trunk

  • Q20.1|

    Double outlet right ventricle

  • Q20.2|

    Double outlet left ventricle

  • Q20.3|

    Discordant ventriculoarterial connection

  • Q20.4|

    Double inlet ventricle

  • Q20.5|

    Discordant atrioventricular connection

  • Q20.6|

    Isomerism of atrial appendages

  • Q20.8|

    Other congenital malformations of cardiac chambers and connections

  • Q20.9|

    Congenital malformation of cardiac chambers and connections, unspecified

  • Q21.0|

    Ventricular septal defect

  • Q21.10|

    Atrial septal defect, unspecified

  • Q21.11|

    Secundum atrial septal defect

  • Q21.12|

    Patent foramen ovale

  • Q21.13|

    Coronary sinus atrial septal defect

  • Q21.14|

    Superior sinus venosus atrial septal defect

  • Q21.15|

    Inferior sinus venosus atrial septal defect

  • Q21.16|

    Sinus venosus atrial septal defect, unspecified

  • Q21.19|

    Other specified atrial septal defect

  • Q21.20|

    Atrioventricular septal defect, unspecified as to partial or complete

  • Q21.21|

    Partial atrioventricular septal defect

  • Q21.22|

    Transitional atrioventricular septal defect

  • Q21.23|

    Complete atrioventricular septal defect

  • Q21.3|

    Tetralogy of Fallot

  • Q21.4|

    Aortopulmonary septal defect

  • Q21.8|

    Other congenital malformations of cardiac septa

  • Q21.9|

    Congenital malformation of cardiac septum, unspecified

  • Q22.0|

    Pulmonary valve atresia

  • Q22.1|

    Congenital pulmonary valve stenosis

  • Q22.2|

    Congenital pulmonary valve insufficiency

  • Q22.3|

    Other congenital malformations of pulmonary valve

  • Q22.4|

    Congenital tricuspid stenosis

  • Q22.5|

    Ebstein's anomaly

  • Q22.6|

    Hypoplastic right heart syndrome

  • Q22.8|

    Other congenital malformations of tricuspid valve

  • Q22.9|

    Congenital malformation of tricuspid valve, unspecified

  • Q23.0|

    Congenital stenosis of aortic valve

  • Q23.1|

    Congenital insufficiency of aortic valve

  • Q23.2|

    Congenital mitral stenosis

  • Q23.3|

    Congenital mitral insufficiency

  • Q23.4|

    Hypoplastic left heart syndrome

  • Q23.81|

    Bicuspid aortic valve

  • Q23.82|

    Congenital mitral valve cleft leaflet

  • Q23.88|

    Other congenital malformations of aortic and mitral valves

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