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
  • Q23.9

    Congenital malformation of aortic and mitral valves, unspecified

  • 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

  • Q25.0

    Patent ductus arteriosus

  • Q25.1

    Coarctation of aorta

  • Q25.21

    Interruption of aortic arch

  • Q25.29

    Other atresia of aorta

  • Q25.3

    Supravalvular aortic stenosis

  • 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

  • Q25.46

    Tortuous aortic arch

  • Q25.47

    Right aortic arch

  • Q25.48

    Anomalous origin of subclavian artery

  • Q25.49

    Other congenital malformations of aorta

  • Q25.5

    Atresia of pulmonary artery

  • Q25.6

    Stenosis of pulmonary artery

  • Q25.71

    Coarctation of pulmonary artery

  • Q25.72

    Congenital pulmonary arteriovenous malformation

  • Q25.79

    Other congenital malformations of pulmonary artery

  • Q25.8

    Other congenital malformations of other great arteries

  • Q25.9

    Congenital malformation of great arteries, unspecified

  • Q26.0

    Congenital stenosis of vena cava

  • Q26.1

    Persistent left superior vena cava

  • Q26.2

    Total anomalous pulmonary venous connection

  • Q26.3

    Partial anomalous pulmonary venous connection

  • Q26.4

    Anomalous pulmonary venous connection, unspecified

  • Q26.5

    Anomalous portal venous connection

  • Q26.6

    Portal vein-hepatic artery fistula

  • Q26.8

    Other congenital malformations of great veins

  • Q26.9

    Congenital malformation of great vein, unspecified

  • Q27.0

    Congenital absence and hypoplasia of umbilical artery

  • Q27.1

    Congenital renal artery stenosis

  • Q27.2

    Other congenital malformations of renal artery

  • Q27.30

    Arteriovenous malformation, site unspecified

  • Q27.31

    Arteriovenous malformation of vessel of upper limb

  • Q27.32

    Arteriovenous malformation of vessel of lower limb

  • Q27.33

    Arteriovenous malformation of digestive system vessel

  • Q27.34

    Arteriovenous malformation of renal vessel

  • Q27.39

    Arteriovenous malformation, other site

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