Short answer · Medically reviewed summary · Last updated: 2026-05-08
Costello Syndrome is a rare genetic disorder characterized by developmental delay, distinct facial features, and an increased risk of specific tumors. Diagnosis is confirmed through genetic testing that identifies a pathogenic variant in the HRAS gene, typically following a clinical evaluation by a medical geneticist. What are the early signs of Costello Syndrome? In infancy, Costello Syndrome often presents with feeding difficulties, failure to thrive, and extreme skin laxity on the hands and feet.
How do I know if I have Costello Syndrome?
Could you have Costello Syndrome? Early signs that prompted real patients to seek diagnosis, plus medically reviewed guidance.
Costello Syndrome is a rare genetic disorder characterized by developmental delay, distinct facial features, and an increased risk of specific tumors. Diagnosis is confirmed through genetic testing that identifies a pathogenic variant in the HRAS gene, typically following a clinical evaluation by a medical geneticist.
What are the early signs of Costello Syndrome?
In infancy, Costello Syndrome often presents with feeding difficulties, failure to thrive, and extreme skin laxity on the hands and feet. Parents may notice that a child has a larger birth weight, followed by significant delays in meeting developmental milestones. Other early indicators include a hoarse voice and a friendly, outgoing personality that is often characteristic of individuals with Costello Syndrome.
How is Costello Syndrome identified and diagnosed?
If you suspect Costello Syndrome, a physician will look for a specific pattern of physical and clinical features. Because many symptoms overlap with other RASopathies, a clinical diagnosis is rarely enough. The definitive way to know if you or a loved one has this condition is through molecular genetic testing targeting the HRAS gene.
- Cardiac evaluation: Screening for hypertrophic cardiomyopathy or arrhythmias.
- Dermatological assessment: Identifying deep palmar/plantar creases and papillomata.
- Developmental screening: Assessing for global developmental delays and intellectual disability.
- Oncology surveillance: Routine monitoring for tumors, as Costello Syndrome carries an increased risk for malignancies like rhabdomyosarcoma.
When should I seek urgent medical evaluation?
While Costello Syndrome is a chronic condition, certain "red flags" require immediate attention. Seek urgent care if there is a sudden change in heart rhythm, unexplained fainting, or the rapid appearance of new skin growths. If a child with Costello Syndrome experiences unexplained persistent pain or a significant change in growth patterns, consult your specialist immediately.
How do I advocate for a diagnosis?
If your concerns are dismissed, bring a summary of documented symptoms to your primary care provider. Request a referral to a clinical geneticist, as they are best equipped to identify the nuances of Costello Syndrome. You are your own best advocate; if you feel unheard, do not hesitate to seek a second opinion at a major academic medical center.
Next steps
- Consult a medical geneticist to discuss HRAS mutation testing.
- Connect with the 13 members of the Costello Syndrome community on DiseaseMaps.org for peer support.
- Maintain a detailed symptom log to share with your healthcare team.
Medical disclaimer: This information is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Costello Syndrome
- Orphanet: Costello Syndrome (ORPHA:209)
- OMIM (Online Mendelian Inheritance in Man): #218040
- Costello Kids: Information for families and clinicians
