| Q90 | Down syndrome |
| Q90.0 | Trisomy 21, nonmosaicism (meiotic nondisjunction) |
| Q90.1 | Trisomy 21, mosaicism (mitotic nondisjunction) |
| Q90.2 | Trisomy 21, translocation |
| Q90.9 | Down syndrome, unspecified |
| Q91 | Trisomy 18 and Trisomy 13 |
| Q91.0 | Trisomy 18, nonmosaicism (meiotic nondisjunction) |
| Q91.1 | Trisomy 18, mosaicism (mitotic nondisjunction) |
| Q91.2 | Trisomy 18, translocation |
| Q91.3 | Trisomy 18, unspecified |
| Q91.4 | Trisomy 13, nonmosaicism (meiotic nondisjunction) |
| Q91.5 | Trisomy 13, mosaicism (mitotic nondisjunction) |
| Q91.6 | Trisomy 13, translocation |
| Q91.7 | Trisomy 13, unspecified |
| Q92 | Other trisomies and partial trisomies of the autosomes, not elsewhere classified |
| Q92.0 | Whole chromosome trisomy, nonmosaicism (meiotic nondisjunction) |
| Q92.1 | Whole chromosome trisomy, mosaicism (mitotic nondisjunction) |
| Q92.2 | Partial trisomy |
| Q92.5 | Duplications with other complex rearrangements |
| Q92.6 | Marker chromosomes |
| Q92.61 | Marker chromosomes in normal individual |
| Q92.62 | Marker chromosomes in abnormal individual |
| Q92.7 | Triploidy and polyploidy |
| Q92.8 | Other specified trisomies and partial trisomies of autosomes |
| Q92.9 | Trisomy and partial trisomy of autosomes, unspecified |
| Q93 | Monosomies and deletions from the autosomes, not elsewhere classified |
| Q93.0 | Whole chromosome monosomy, nonmosaicism (meiotic nondisjunction) |
| Q93.1 | Whole chromosome monosomy, mosaicism (mitotic nondisjunction) |
| Q93.2 | Chromosome replaced with ring, dicentric or isochromosome |
| Q93.3 | Deletion of short arm of chromosome 4 |
| Q93.4 | Deletion of short arm of chromosome 5 |
| Q93.5 | Other deletions of part of a chromosome |
| Q93.7 | Deletions with other complex rearrangements |
| Q93.8 | Other deletions from the autosomes |
| Q93.81 | Velo-cardio-facial syndrome |
| Q93.88 | Other microdeletions |
| Q93.89 | Other deletions from the autosomes |
| Q93.9 | Deletion from autosomes, unspecified |
| Q95 | Balanced rearrangements and structural markers, not elsewhere classified |
| Q95.0 | Balanced translocation and insertion in normal individual |
| Q95.1 | Chromosome inversion in normal individual |
| Q95.2 | Balanced autosomal rearrangement in abnormal individual |
| Q95.3 | Balanced sex/autosomal rearrangement in abnormal individual |
| Q95.5 | Individual with autosomal fragile site |
| Q95.8 | Other balanced rearrangements and structural markers |
| Q95.9 | Balanced rearrangement and structural marker, unspecified |
| Q96 | Turner's syndrome |
| Q96.0 | Karyotype 45, X |
| Q96.1 | Karyotype 46, X iso (Xq) |
| Q96.2 | Karyotype 46, X with abnormal sex chromosome, except iso (Xq) |
| Q96.3 | Mosaicism, 45, X/46, XX or XY |
| Q96.4 | Mosaicism, 45, X/other cell line(s) with abnormal sex chromosome |
| Q96.8 | Other variants of Turner's syndrome |
| Q96.9 | Turner's syndrome, unspecified |
| Q97 | Other sex chromosome abnormalities, female phenotype, not elsewhere classified |
| Q97.0 | Karyotype 47, XXX |
| Q97.1 | Female with more than three X chromosomes |
| Q97.2 | Mosaicism, lines with various numbers of X chromosomes |
| Q97.3 | Female with 46, XY karyotype |
| Q97.8 | Other specified sex chromosome abnormalities, female phenotype |
| Q97.9 | Sex chromosome abnormality, female phenotype, unspecified |
| Q98 | Other sex chromosome abnormalities, male phenotype, not elsewhere classified |
| Q98.0 | Klinefelter syndrome karyotype 47, XXY |
| Q98.1 | Klinefelter syndrome, male with more than two X chromosomes |
| Q98.3 | Other male with 46, XX karyotype |
| Q98.4 | Klinefelter syndrome, unspecified |
| Q98.5 | Karyotype 47, XYY |
| Q98.6 | Male with structurally abnormal sex chromosome |
| Q98.7 | Male with sex chromosome mosaicism |
| Q98.8 | Other specified sex chromosome abnormalities, male phenotype |
| Q98.9 | Sex chromosome abnormality, male phenotype, unspecified |
| Q99 | Other chromosome abnormalities, not elsewhere classified |
| Q99.0 | Chimera 46, XX/46, XY |
| Q99.1 | 46, XX true hermaphrodite |
| Q99.2 | Fragile X chromosome |
| Q99.8 | Other specified chromosome abnormalities |
| Q99.9 | Chromosomal abnormality, unspecified |