What is the prevalence of Costello Syndrome?

Costello syndrome is an ultra-rare genetic disorder with an estimated global prevalence of approximately 1 in 300,000 to 1 in 1.25 million individuals. While exact numbers are difficult to track due to potential underdiagnosis, it is considered an ultra-rare condition that affects males and females equally across all ethnic and geographic populations.

How common is Costello syndrome?

Costello syndrome is classified as an ultra-rare condition, meaning it is significantly less common than many other genetic syndromes. Because the clinical presentation can be subtle in early infancy or overlap with other RASopathies, many experts believe the true prevalence may be higher than currently reported figures. Within the DiseaseMaps.org community, 13 individuals have shared their experiences, providing a vital, real-world window into the lives of those navigating this rare diagnosis.

What factors influence prevalence data?

Accurate epidemiological data for Costello syndrome remains challenging to obtain due to several clinical and systemic factors:

• Diagnostic Challenges: Early symptoms may mimic other conditions, leading to initial misdiagnosis or delayed confirmation.


• Genetic Testing Access: Increased availability of HRAS gene sequencing has improved detection, but barriers to testing persist in many regions.


• Reporting Bias: Rare disease registries often capture only those who have access to specialized academic medical centers.

Is there a gender or age distribution for Costello syndrome?

Costello syndrome affects males and females with equal frequency, and there is no known ethnic or geographic predilection. Regarding age of onset, Costello syndrome is a congenital condition, meaning it is present from birth. While it is predominantly diagnosed in infancy or early childhood due to developmental delays and characteristic physical features, it is a lifelong condition that persists into adulthood, requiring ongoing multidisciplinary care.

Next steps

• Consult a clinical geneticist to confirm a diagnosis through targeted HRAS mutation testing.


• Join the DiseaseMaps.org community to connect with other families and share experiences living with Costello syndrome.


• Review resources from the Costello Syndrome Family Network for the latest clinical management guidelines.

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): Costello Syndrome.


• Orphanet: Costello Syndrome (ORPHA:207).


• OMIM (Online Mendelian Inheritance in Man): HRAS-related Costello Syndrome (#218040).


• Costello Syndrome Family Network (CSFN).