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Costello syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Costello syndrome

Costello syndrome is a rare genetic condition characterized by developmental delays, distinctive facial features, heart problems, and an increased risk of developing certain tumors.

Overview

Costello syndrome affects many parts of the body. Individuals with this condition often experience delayed development, loose skin folds, flexible joints, and short stature. While infants may be larger than average at birth, they often face feeding difficulties and grow more slowly than their peers.

Symptoms

  • Developmental and Neurological: Delayed milestones (speaking, sitting, walking), intellectual disabilities, seizures, weak muscle tone (hypotonia), and Chiari I malformation.
  • Facial Features: Prominent forehead, full cheeks, and full lips.
  • Heart Health: Arrhythmia, structural heart defects, and heart muscle enlargement.
  • Gastrointestinal: Constipation and gastroesophageal reflux disease (GERD).
  • Vision and Hearing: Nearsightedness, farsightedness, strabismus, and hearing loss.
  • Other: Tight Achilles tendons, recurrent respiratory infections, dry/thickened skin, and dental problems.

Tumor Risk

Beginning in early childhood, individuals have a higher risk of developing tumors. Common noncancerous growths include papillomas (wart-like growths). Cancerous tumors, such as rhabdomyosarcoma (muscle tissue cancer) and neuroblastoma (nerve cell tumor), have been reported. Some teenagers may develop transitional cell carcinoma of the bladder.

Causes

Costello syndrome is caused by variants in the HRAS gene. This gene produces the H-Ras protein, which helps control cell growth and division. Variants lead to an overactive protein that directs cells to grow and divide excessively, which can lead to tumor development. This condition belongs to a group of disorders known as RASopathies, which involve the RAS/MAPK signaling pathway.

Inheritance

This condition is inherited in an autosomal dominant pattern. Most cases result from new (de novo) variants that occur during the formation of reproductive cells or in early embryonic development, meaning there is typically no family history of the disorder.

Frequently Asked Questions

Many infants have poor suck‑swallow coordination and gastroesophageal reflux. Strategies include positioning the baby upright during feeds, using thickened feeds, and small, frequent meals. If weight gain remains inadequate after 2–3 months of these measures, a referral to a pediatric gastroenterologist for a feeding evaluation is advised. Options may include a nasogastric tube or gastrostomy tube to ensure adequate calories and growth.
Skin care focuses on moisturization with emollients to reduce dryness and cracking; silicone gel sheets can help flatten papillomas. For joint laxity, a tailored physical‑therapy program emphasizes low‑impact strengthening (e.g., swimming, Pilates) and proprioceptive training to improve stability. Orthotic devices such as custom‑made shoes or wrist splints can support hypermobile joints and reduce the risk of sprains. Regular monitoring by a physiotherapist helps adjust the program as the child grows.
Screening should start early. Recommended surveillance includes: (1) abdominal ultrasound every 6–12 months to detect renal or hepatic lesions; (2) chest X‑ray or low‑dose CT annually for rhabdomyosarcoma; (3) urine cytology every year after age 10 for bladder transitional cell carcinoma; and (4) dermatologic exam every 6 months for papillomas that can mask malignancy. Any new lump, persistent pain, or unexplained weight loss should prompt immediate imaging.
Baseline evaluation includes an echocardiogram, electrocardiogram (ECG), and, if indicated, cardiac MRI to look for hypertrophic cardiomyopathy, valve abnormalities, or arrhythmias. Follow‑up imaging is recommended every 1–2 years, or sooner if symptoms develop. Red‑flag signs include unexplained fatigue, shortness of breath, chest pain, fainting spells, or a rapid heartbeat—these warrant urgent cardiology review and possibly an emergency ECG.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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