Short answer · Medically reviewed summary · Last updated: 2026-05-08
Pallister-Killian Syndrome (PKS), also known as Tetrasomy 12p, does not have a unique, disease-specific ICD-10 or ICD-9 code; it is typically classified under broader categories for chromosomal abnormalities. In clinical practice, providers often use ICD-10 code Q92.7 (Chromosome 12, tetrasomy) or Q92.8 (Other specified trisomies and partial trisomies of autosomes) to document this condition. What is the classification of Pallister-Killian Syndrome? Pallister-Killian Syndrome is a rare sporadic genetic disorder characterized by the presence of an extra chromosome 12 (isochromosome 12p) in some, but not all, of the body's cells, a phenomenon known as tissue-specific mosaicism.
ICD10 code of Pallister-Killian Syndrome / Tetrasomy 12p and ICD9 code
ICD-10 and ICD-9 codes for Pallister-Killian Syndrome / Tetrasomy 12p, with classification details for clinicians, coders and patients.
Pallister-Killian Syndrome (PKS), also known as Tetrasomy 12p, does not have a unique, disease-specific ICD-10 or ICD-9 code; it is typically classified under broader categories for chromosomal abnormalities. In clinical practice, providers often use ICD-10 code Q92.7 (Chromosome 12, tetrasomy) or Q92.8 (Other specified trisomies and partial trisomies of autosomes) to document this condition.
What is the classification of Pallister-Killian Syndrome?
Pallister-Killian Syndrome is a rare sporadic genetic disorder characterized by the presence of an extra chromosome 12 (isochromosome 12p) in some, but not all, of the body's cells, a phenomenon known as tissue-specific mosaicism. Because the genetic mechanism involves a mosaic tetrasomy, medical billing often relies on codes for general chromosomal anomalies. Clinicians may also use codes related to the specific manifestations of Pallister-Killian Syndrome, such as developmental delay (F88) or epilepsy (G40), to support insurance authorizations for therapies.
How is a diagnosis of Tetrasomy 12p confirmed?
Diagnosis of Pallister-Killian Syndrome is complex because the extra chromosome is often absent in blood lymphocytes but present in skin fibroblasts. To confirm Tetrasomy 12p, geneticists typically perform:
- Skin biopsy for fibroblast chromosomal analysis.
- Buccal smear or specialized blood testing (though these may yield false negatives).
- Chromosomal microarray (CMA) to identify the extra genetic material on the short arm of chromosome 12.
Is Pallister-Killian Syndrome hereditary?
Pallister-Killian Syndrome is almost universally a sporadic occurrence, meaning it is not inherited from parents. The development of the isochromosome 12p happens as a random event during early embryonic development. Currently, there is no evidence that parental age or environmental factors increase the risk of having a child with Pallister-Killian Syndrome. At DiseaseMaps.org, we have 9 members who have shared their experiences, providing a valuable network for families navigating this rare diagnosis.
Next steps
- Consult with a clinical geneticist to review diagnostic testing results and ensure accurate classification for medical records.
- Connect with the 9 community members at DiseaseMaps.org to share lived experiences and coping strategies.
- Maintain a comprehensive file of clinical reports, as the lack of a specific ICD code for Pallister-Killian Syndrome can sometimes complicate insurance coverage for specialized therapies.
Medical disclaimer: This information is for educational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or qualified health provider with any questions regarding a medical condition.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Pallister-Killian syndrome.
- Orphanet: Pallister-Killian syndrome (ORPHA:650).
- OMIM (Online Mendelian Inheritance in Man): Tetrasomy 12p Mosaicism (601803).
- Pallister-Killian Syndrome Foundation.
