| Q00 | Anencephaly and similar malformations |
| Q00.0 | Anencephaly |
| Q00.1 | Craniorachischisis |
| Q00.2 | Iniencephaly |
| Q01 | Encephalocele |
| Q01.0 | Frontal encephalocele |
| Q01.1 | Nasofrontal encephalocele |
| Q01.2 | Occipital encephalocele |
| Q01.8 | Encephalocele of other sites |
| Q01.9 | Encephalocele, unspecified |
| Q02 | Microcephaly |
| Q03 | Congenital hydrocephalus |
| Q03.0 | Malformations of aqueduct of Sylvius |
| Q03.1 | Atresia of foramina of Magendie and Luschka |
| Q03.8 | Other congenital hydrocephalus |
| Q03.9 | Congenital hydrocephalus, unspecified |
| Q04 | Other congenital malformations of brain |
| Q04.0 | Congenital malformations of corpus callosum |
| Q04.1 | Arhinencephaly |
| Q04.2 | Holoprosencephaly |
| Q04.3 | Other reduction deformities of brain |
| Q04.4 | Septo-optic dysplasia of brain |
| Q04.5 | Megalencephaly |
| Q04.6 | Congenital cerebral cysts |
| Q04.8 | Other specified congenital malformations of brain |
| Q04.9 | Congenital malformation of brain, unspecified |
| Q05 | Spina bifida |
| Q05.0 | Cervical spina bifida with hydrocephalus |
| Q05.1 | Thoracic spina bifida with hydrocephalus |
| Q05.2 | Lumbar spina bifida with hydrocephalus |
| Q05.3 | Sacral spina bifida with hydrocephalus |
| Q05.4 | Unspecified spina bifida with hydrocephalus |
| Q05.5 | Cervical spina bifida without hydrocephalus |
| Q05.6 | Thoracic spina bifida without hydrocephalus |
| Q05.7 | Lumbar spina bifida without hydrocephalus |
| Q05.8 | Sacral spina bifida without hydrocephalus |
| Q05.9 | Spina bifida, unspecified |
| Q06 | Other congenital malformations of spinal cord |
| Q06.0 | Amyelia |
| Q06.1 | Hypoplasia and dysplasia of spinal cord |
| Q06.2 | Diastematomyelia |
| Q06.3 | Other congenital cauda equina malformations |
| Q06.4 | Hydromyelia |
| Q06.8 | Other specified congenital malformations of spinal cord |
| Q06.9 | Congenital malformation of spinal cord, unspecified |
| Q07 | Other congenital malformations of nervous system |
| Q07.0 | Arnold-Chiari syndrome |
| Q07.00 | Arnold-Chiari syndrome without spina bifida or hydrocephalus |
| Q07.01 | Arnold-Chiari syndrome with spina bifida |
| Q07.02 | Arnold-Chiari syndrome with hydrocephalus |
| Q07.03 | Arnold-Chiari syndrome with spina bifida and hydrocephalus |
| Q07.8 | Other specified congenital malformations of nervous system |
| Q07.9 | Congenital malformation of nervous system, unspecified |