2021 ICD-10-CM Diagnosis Code Q99.2

Fragile X chromosome

    2016 2017 2018 2019 2020 2021 Billable/Specific Code POA Exempt
  • Q99.2 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2021 edition of ICD-10-CM Q99.2 became effective on October 1, 2020.
  • This is the American ICD-10-CM version of Q99.2 - other international versions of ICD-10 Q99.2 may differ.
Applicable To
  • Fragile X syndrome
The following code(s) above Q99.2 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to Q99.2:
  • Q00-Q99
    2021 ICD-10-CM Range Q00-Q99

    Congenital malformations, deformations and chromosomal abnormalities

    • Codes from this chapter are not for use on maternal records
    Type 2 Excludes
    • inborn errors of metabolism (E70-E88)
    Congenital malformations, deformations and chromosomal abnormalities
  • Q90-Q99
    2021 ICD-10-CM Range Q90-Q99

    Chromosomal abnormalities, not elsewhere classified

    Type 2 Excludes
    • mitochondrial metabolic disorders (E88.4-)
    Chromosomal abnormalities, not elsewhere classified
Approximate Synonyms
  • Fragile x syndrome
Clinical Information
  • A condition characterized genotypically by mutation of the distal end of the long arm of the x chromosome (at gene loci fraxa or fraxe) and phenotypically by cognitive impairment, hyperactivity, seizures, language delay, and enlargement of the ears, head, and testes. Intellectual disability occurs in nearly all males and roughly 50% of females with the full mutation of fraxa. (from menkes, textbook of child neurology, 5th ed, p226)
  • A genetic syndrome caused by mutations in the fmr1 gene which is responsible for the expression of the fragile x mental retardation 1 protein. This protein participates in neural development. This syndrome is manifested with mental, emotional, behavioral, physical, and learning disabilities.
  • An inherited disease characterized by the presence of a fragile site in the long arm of chromosome x. It is a common cause of mental retardation, second only in frequency to the down syndrome (trisomy 21). The expression varies with mental retardation, macroorchidism, high-pitched voice, narrow face, long jaw, large ears, prominent forehead, highly arched narrow palate, and joint laxity as the most common characteristics. Microcephaly, typical facies, shortness of stature, and absence of macroorchidism characterize the renpenning but not martin-bell syndrome. Major characteristics of the martin-bell syndrome include: mental retardation with speech and behavioral disorders; connective tissue dysplasia; square facies with midfacial hypoplasia; slightly below normal height without intra- uterine growth retardation; average or above average head circumference; large and frequently anteverted ears; prominent forehead and supraorbital ridges; large nose; prominent mandible which becomes apparent during adolescence; joint laxity; minor limb anomalies; dermatoglyphic abnormalities; and seizures.
  • Fragile x syndrome is the most common form of inherited mental retardation. A problem with a specific gene causes the disease. Normally, the gene makes a protein you need for brain development. But the mutation causes a person to make little or none of the protein, which results in the symptoms of fragile x. People with only a small change in the gene might not show any signs of fragile x. People with bigger changes can have severe symptoms. These might include
    • intelligence problems, ranging from learning disabilities to severe mental retardation
    • social and emotional problems, such as aggression in boys or shyness in girls
    • speech and language problems, especially in boys
    fragile x has no cure. You can treat some symptoms with educational, behavioral or physical therapy, and with medicines. Getting treatment early for fragile x can help. nih: national institute of child health and human development
  • X-linked recessive disorder characterized by mental retardation and large head, jaw, ears, and testes; premutation alleles in unaffected carriers give rise to significantly amplified repeats in affected progeny.
Present On Admission
POA Help
"Present On Admission" is defined as present at the time the order for inpatient admission occurs — conditions that develop during an outpatient encounter, including emergency department, observation, or outpatient surgery, are considered POA.
  • Q99.2 is considered exempt from POA reporting.
ICD-10-CM Q99.2 is grouped within Diagnostic Related Group(s) (MS-DRG v38.0):
  • 884 Organic disturbances and intellectual disability

Convert Q99.2 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change

Diagnosis Index entries containing back-references to Q99.2:

ICD-10-CM Codes Adjacent To Q99.2
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
R00 Abnormalities of heart beat
R00.0 Tachycardia, unspecified
R00.1 Bradycardia, unspecified
R00.2 Palpitations
R00.8 Other abnormalities of heart beat
R00.9 Unspecified abnormalities of heart beat
R01 Cardiac murmurs and other cardiac sounds
R01.0 Benign and innocent cardiac murmurs

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.