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
  • 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|

    Congenital malformations of pulmonary and tricuspid valves

  • 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|

    Congenital malformations of aortic and mitral valves

  • 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

  • Q23.8|

    Other congenital malformations of aortic and mitral valves

  • Q23.81|

    Bicuspid aortic valve

  • Q23.82|

    Congenital mitral valve cleft leaflet

  • Q23.88|

    Other congenital malformations of aortic and mitral valves

  • Q23.9|

    Congenital malformation of aortic and mitral valves, unspecified

  • Q24|

    Other congenital malformations of heart

  • Q24.0|

    Dextrocardia

  • Q24.1|

    Levocardia

  • Q24.2|

    Cor triatriatum

  • Q24.3|

    Pulmonary infundibular stenosis

  • Q24.4|

    Congenital subaortic stenosis

  • Q24.5|

    Malformation of coronary vessels

  • Q24.6|

    Congenital heart block

  • Q24.8|

    Other specified congenital malformations of heart

  • Q24.9|

    Congenital malformation of heart, unspecified

  • Q25|

    Congenital malformations of great arteries

  • Q25.0|

    Patent ductus arteriosus

  • Q25.1|

    Coarctation of aorta

  • Q25.2|

    Atresia of aorta

  • Q25.21|

    Interruption of aortic arch

  • Q25.29|

    Other atresia of aorta

  • Q25.3|

    Supravalvular aortic stenosis

  • Q25.4|

    Other congenital malformations of aorta

  • Q25.40|

    Congenital malformation of aorta unspecified

  • Q25.41|

    Absence and aplasia of aorta

  • Q25.42|

    Hypoplasia of aorta

  • Q25.43|

    Congenital aneurysm of aorta

  • Q25.44|

    Congenital dilation of aorta

  • Q25.45|

    Double aortic arch

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