Chromosomal abnormalities, not elsewhere classified (Q90-Q99)
chapter 17: Congenital Malformations, Deformations and Chromosomal Abnormalities
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Instructional notes
Excludes2: not included here, code separately if applicable
- mitochondrial metabolic disorders (E88.4-)
Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
Assign Q00-QA1 codes for documented congenital anomalies or genetic disorders at any age, coding non-inherent manifestations separately and sequencing Z38 first on the birth admission.
All codes under Q90-Q99
Q90-Q99 can't be used on a claim. Pick a billable code below; grey headings group them.
- Q90Down syndrome
- Q90.0Trisomy 21, nonmosaicism (meiotic nondisjunction)
- Q90.1Trisomy 21, mosaicism (mitotic nondisjunction)
- Q90.2Trisomy 21, translocation
- Q90.9Down syndrome, unspecified
- Q91Trisomy 18 and Trisomy 13
- Q91.0Trisomy 18, nonmosaicism (meiotic nondisjunction)
- Q91.1Trisomy 18, mosaicism (mitotic nondisjunction)
- Q91.2Trisomy 18, translocation
- Q91.3Trisomy 18, unspecified
- Q91.4Trisomy 13, nonmosaicism (meiotic nondisjunction)
- Q91.5Trisomy 13, mosaicism (mitotic nondisjunction)
- Q91.6Trisomy 13, translocation
- Q91.7Trisomy 13, unspecified
- Q92Other trisomies and partial trisomies of the autosomes, not elsewhere classified
- Q92.0Whole chromosome trisomy, nonmosaicism (meiotic nondisjunction)
- Q92.1Whole chromosome trisomy, mosaicism (mitotic nondisjunction)
- Q92.2Partial trisomy
- Q92.5Duplications with other complex rearrangements
- Q92.6Marker chromosomes
- Q92.61Marker chromosomes in normal individual
- Q92.62Marker chromosomes in abnormal individual
- Q92.7Triploidy and polyploidy
- Q92.8Other specified trisomies and partial trisomies of autosomes
- Q92.9Trisomy and partial trisomy of autosomes, unspecified
- Q93Monosomies and deletions from the autosomes, not elsewhere classified
- Q93.0Whole chromosome monosomy, nonmosaicism (meiotic nondisjunction)
- Q93.1Whole chromosome monosomy, mosaicism (mitotic nondisjunction)
- Q93.2Chromosome replaced with ring, dicentric or isochromosome
- Q93.3Deletion of short arm of chromosome 4
- Q93.4Deletion of short arm of chromosome 5
- Q93.5Other deletions of part of a chromosome
- Q93.51Angelman syndrome
- Q93.52Phelan-McDermid syndrome
- Q93.59Other deletions of part of a chromosome
- Q93.7Deletions with other complex rearrangements
- Q93.8Other deletions from the autosomes
- Q93.81Velo-cardio-facial syndrome
- Q93.82Williams syndrome
- Q93.88Other microdeletions
- Q93.89Other deletions from the autosomes
- Q93.9Deletion from autosomes, unspecified
- Q95Balanced rearrangements and structural markers, not elsewhere classified
- Q95.0Balanced translocation and insertion in normal individual
- Q95.1Chromosome inversion in normal individual
- Q95.2Balanced autosomal rearrangement in abnormal individual
- Q95.3Balanced sex/autosomal rearrangement in abnormal individual
- Q95.5Individual with autosomal fragile site
- Q95.8Other balanced rearrangements and structural markers
- Q95.9Balanced rearrangement and structural marker, unspecified
- Q96Turner's syndrome
- Q96.0Karyotype 45, X
- Q96.1Karyotype 46, X iso (Xq)
- Q96.2Karyotype 46, X with abnormal sex chromosome, except iso (Xq)
- Q96.3Mosaicism, 45, X/46, XX or XY
- Q96.4Mosaicism, 45, X/other cell line(s) with abnormal sex chromosome
- Q96.8Other variants of Turner's syndrome
- Q96.9Turner's syndrome, unspecified
- Q97Other sex chromosome abnormalities, female phenotype, not elsewhere classified
- Q97.0Karyotype 47, XXX
- Q97.1Female with more than three X chromosomes
- Q97.2Mosaicism, lines with various numbers of X chromosomes
- Q97.3Female with 46, XY karyotype
- Q97.8Other specified sex chromosome abnormalities, female phenotype
- Q97.9Sex chromosome abnormality, female phenotype, unspecified
- Q98Other sex chromosome abnormalities, male phenotype, not elsewhere classified
- Q98.0Klinefelter syndrome karyotype 47, XXY
- Q98.1Klinefelter syndrome, male with more than two X chromosomes
- Q98.3Other male with 46, XX karyotype
- Q98.4Klinefelter syndrome, unspecified
- Q98.5Karyotype 47, XYY
- Q98.6Male with structurally abnormal sex chromosome
- Q98.7Male with sex chromosome mosaicism
- Q98.8Other specified sex chromosome abnormalities, male phenotype
- Q98.9Sex chromosome abnormality, male phenotype, unspecified
- Q99Other chromosome abnormalities, not elsewhere classified
- Q99.0Chimera 46, XX/46, XY
- Q99.146, XX true hermaphrodite
- Q99.2Fragile X chromosome
- Q99.8Other specified chromosome abnormalities
- Q99.81Usher syndrome
- Q99.811Usher syndrome, type 1
- Q99.812Usher syndrome, type 2
- Q99.813Usher syndrome, type 3
- Q99.818Other Usher syndrome
- Q99.819Usher syndrome, unspecified
- Q99.89Other specified chromosome abnormalities
- Q99.9Chromosomal abnormality, unspecified
Q90-Q99 MS-DRGs
This code does not group to an MS-DRG as a principal diagnosis.
Other codes that refer to Q90-Q99
Notes on these codes point to Q90-Q99.
About the condition
Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.
Down Syndrome
Down syndrome is a condition in which a person has an extra chromosome or an extra piece of a chromosome. This extra copy changes how a baby's body and brain develop. It can cause both mental and physical challenges during their lifetime. Even though people with Down syndrome might act and look similar, each person has different abilities.
Read more about down syndrome on MedlinePlus