Short answer · Medically reviewed summary · Last updated: 2026-05-08
Coffin-Siris Syndrome (CSS) is primarily classified under ICD-10 code Q87.89 (Other specified congenital malformation syndromes, not elsewhere classified) and does not have a unique, dedicated ICD-9 code, historically falling under 759.89 (Other specified congenital anomalies). Because Coffin-Siris Syndrome is a rare genetic disorder, it often requires the use of these broader "catch-all" codes for insurance and medical record documentation. What is the clinical significance of Coffin-Siris Syndrome? Coffin-Siris Syndrome is a rare genetic condition characterized by developmental delay, intellectual disability, and distinctive physical features, most notably hypoplasia or aplasia of the fifth digit nail or phalanx.
ICD10 code of Coffin Siris Syndrome and ICD9 code
ICD-10 and ICD-9 codes for Coffin Siris Syndrome, with classification details for clinicians, coders and patients.
Coffin-Siris Syndrome (CSS) is primarily classified under ICD-10 code Q87.89 (Other specified congenital malformation syndromes, not elsewhere classified) and does not have a unique, dedicated ICD-9 code, historically falling under 759.89 (Other specified congenital anomalies). Because Coffin-Siris Syndrome is a rare genetic disorder, it often requires the use of these broader "catch-all" codes for insurance and medical record documentation.
What is the clinical significance of Coffin-Siris Syndrome?
Coffin-Siris Syndrome is a rare genetic condition characterized by developmental delay, intellectual disability, and distinctive physical features, most notably hypoplasia or aplasia of the fifth digit nail or phalanx. Currently, 212 people with Coffin-Siris Syndrome have joined the DiseaseMaps.org community to share their experiences, highlighting the diverse clinical presentation of the disorder.
How is Coffin-Siris Syndrome diagnosed?
Diagnosis of Coffin-Siris Syndrome is typically confirmed through molecular genetic testing. Since the discovery that Coffin-Siris Syndrome is often caused by mutations in genes involved in the BAF chromatin remodeling complex (such as ARID1A, ARID1B, SMARCA4, and SMARCE1), clinical geneticists use gene panels or whole-exome sequencing to identify the underlying cause.
What are the common features of Coffin-Siris Syndrome?
The clinical manifestations of Coffin-Siris Syndrome are broad and vary significantly between individuals. Key features often observed by clinicians include:
- Hypoplasia or absence of the fifth fingernail and/or distal phalanx.
- Characteristic coarse facial features, including a wide mouth and thick eyebrows.
- Mild to severe intellectual disability or developmental delay.
- Feeding difficulties and recurrent respiratory infections in infancy.
- Hypertrichosis (excessive hair growth) or sparse scalp hair.
Is Coffin-Siris Syndrome hereditary?
Most cases of Coffin-Siris Syndrome occur as a *de novo* (sporadic) mutation, meaning the genetic change is not inherited from either parent. However, rare instances of familial transmission have been reported, making genetic counseling essential for families navigating a Coffin-Siris Syndrome diagnosis.
Next steps
- Consult with a clinical geneticist to discuss molecular testing and family planning.
- Connect with the Coffin-Siris Syndrome community at DiseaseMaps.org to share insights with others.
- Schedule multidisciplinary evaluations, including neurology, cardiology, and speech therapy, to manage the multisystem nature of the syndrome.
Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Coffin-Siris Syndrome.
- Orphanet: Coffin-Siris Syndrome (ORPHA:1879).
- OMIM (Online Mendelian Inheritance in Man): Entry #135900.
- Coffin-Siris Syndrome Foundation: Patient resources and support.
