Short answer · Medically reviewed summary · Last updated: 2026-05-08
Idic 15, also known as Isodicentric Chromosome 15 syndrome, is considered an ultra-rare genetic condition, with an estimated prevalence of approximately 1 in 30,000 births. Because many cases are likely misdiagnosed or undiagnosed, true prevalence data remains difficult to quantify accurately, though it is recognized as a significant cause of developmental delay and autism spectrum disorder. How common is Idic 15 in the general population? While exact global numbers are elusive due to the challenges of clinical identification, Idic 15 is classified as an ultra-rare condition.
What is the prevalence of Idic 15?
Prevalence of Idic 15: how many people are affected worldwide, differences by sex and region, with sources.
Idic 15, also known as Isodicentric Chromosome 15 syndrome, is considered an ultra-rare genetic condition, with an estimated prevalence of approximately 1 in 30,000 births. Because many cases are likely misdiagnosed or undiagnosed, true prevalence data remains difficult to quantify accurately, though it is recognized as a significant cause of developmental delay and autism spectrum disorder.
How common is Idic 15 in the general population?
While exact global numbers are elusive due to the challenges of clinical identification, Idic 15 is classified as an ultra-rare condition. Incidence is estimated at roughly 1 in 30,000 live births, according to data synthesized by the NIH Genetic and Rare Diseases (GARD) Information Center. Because the symptoms of Idic 15 overlap significantly with other neurodevelopmental disorders, many individuals may remain undiagnosed, suggesting the actual prevalence may be higher than current clinical reports indicate.
Are there variations in how Idic 15 affects different groups?
Idic 15 affects both males and females, with no clear evidence suggesting a significant gender-based disparity in incidence. The condition is primarily identified in the pediatric population, as early developmental milestones are often missed, leading to diagnosis in early childhood. However, as diagnostic technology like chromosomal microarray (CMA) improves, more adults are receiving a formal diagnosis of Idic 15. There are currently no known ethnic or geographic clusters associated with this condition; it occurs globally across all populations.
Why is collecting accurate prevalence data for Idic 15 challenging?
Data collection for Idic 15 faces several hurdles that prevent precise statistical modeling:
- Diagnostic overshadowing: Symptoms often lead to a generic diagnosis of autism or global developmental delay without identifying the specific underlying genetic cause.
- Genetic testing access: The specialized testing required to detect the extra genetic material in Idic 15 is not universally available in all healthcare settings.
- Under-reporting: Many mild cases may never reach specialized genetic clinics.
At DiseaseMaps.org, we have begun documenting the lived experience of this condition, with 2 community members currently sharing their journey with Idic 15, providing a vital, real-world perspective that complements clinical statistics.
Next steps
- Consult a clinical geneticist to discuss whether microarray testing is appropriate for your family.
- Connect with the Idic 15 community on DiseaseMaps.org to share experiences and find peer support.
- Review resources from the Dup15q Alliance for the latest research and family support services.
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 (GARD) Information Center: "Isodicentric 15q"
- Orphanet: "Supernumerary marker chromosome 15"
- OMIM (Online Mendelian Inheritance in Man): #608636
- Dup15q Alliance: Clinical and research resources for Idic 15
