National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Costello syndrome



Costello syndrome is a rare condition that affects many different parts of the body. Signs and symptoms generally include developmental delay, intellectual disability, distinctive facial features, loose folds of extra skin (especially on the hands and feet), and unusually flexible joints. Affected people may also have heart abnormalities such as tachycardia, structural heart defects, and hypertrophic cardiomyopathy. Beginning in early childhood, people with Costello syndrome additionally have an increased risk to develop certain cancerous and noncancerous tumors. Costello syndrome is caused by changes (mutations) in the HRAS gene. It is considered an autosomal dominant condition, but almost all cases are the result of de novo gene mutations and occur in people with no family history of the condition.[1][2][3] Treatment is based on the signs and symptoms present in each person.[3]

Costello syndrome belongs to a group of related conditions called the RASopathies. These conditions have some overlapping features and are all caused by genetic changes that disrupt the body's RAS pathway, affecting growth and development. The features of Costello syndrome overlap significantly with two of the RASopathies, cardiofaciocutaneous (CFC) syndrome and Noonan syndrome.

Last updated: 3/9/2016

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormal fingernail morphology
Abnormal fingernails
Abnormality of the fingernails
[ more ]
0001231
Acanthosis nigricans
Darkened and thickened skin
0000956
Concave nail
Spoon-shaped nails
0001598
Deep-set nails 0001814
Delayed skeletal maturation
Delayed bone maturation
Delayed skeletal development
[ more ]
0002750
Depressed nasal bridge
Depressed bridge of nose
Flat bridge of nose
Flat nasal bridge
Flat, nasal bridge
Flattened nasal bridge
Low nasal bridge
Low nasal root
[ more ]
0005280
Failure to thrive in infancy
Faltering weight in infancy
Weight faltering in infancy
[ more ]
0001531
Hyperkeratosis 0000962
Lack of skin elasticity 0100679
Macrocephaly
Increased size of skull
Large head
Large head circumference
[ more ]
0000256
Narrow palate
Narrow roof of mouth
0000189
Pulmonic stenosis
Narrowing of pulmonic valve
0001642
Redundant skin
Loose redundant skin
Redundant skin folds
Sagging, redundant skin
[ more ]
0001582
Short neck
Decreased length of neck
0000470
Short stature
Decreased body height
Small stature
[ more ]
0004322
Ventricular septal defect
Hole in heart wall separating two lower heart chambers
0001629
Woolly hair
Kinked hair
0002224
30%-79% of people have these symptoms
Abnormal dermatoglyphics
Abnormal fingerprints
0007477
Abnormality of dental enamel
Abnormal tooth enamel
Enamel abnormalities
Enamel abnormality
[ more ]
0000682
Cerebral cortical atrophy
Decrease in size of the outer layer of the brain due to loss of brain cells
0002120
Cryptorchidism
Undescended testes
Undescended testis
[ more ]
0000028
Epicanthus
Eye folds
Prominent eye folds
[ more ]
0000286
Full cheeks
Apple cheeks
Big cheeks
Increased size of cheeks
Large cheeks
[ more ]
0000293
Gastroesophageal reflux
Acid reflux
Acid reflux disease
Heartburn
[ more ]
0002020
Hypertrophic cardiomyopathy
Enlarged and thickened heart muscle
0001639
Hypoplastic toenails
Underdeveloped toenails
0001800
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Joint hyperflexibility
Joints move beyond expected range of motion
0005692
Keratoconus
Bulging cornea
0000563
Macroglossia
Abnormally large tongue
Increased size of tongue
Large tongue
[ more ]
0000158
Mitral valve prolapse 0001634
Papilloma 0012740
Polyhydramnios
High levels of amniotic fluid
0001561
Strabismus
Cross-eyed
Squint
Squint eyes
[ more ]
0000486
Thick lower lip vermilion
Increased volume of lower lip
Plump lower lip
Prominent lower lip
[ more ]
0000179
Thickened Achilles tendon 0004690
Thickened nuchal skin fold
Thickened skin folds of neck
Thickened skin over the neck
[ more ]
0000474
Ulnar deviation of finger
Finger bends toward pinky
0009465
5%-29% of people have these symptoms
Coarse facial features
Coarse facial appearance
0000280
Generalized hyperpigmentation 0007440
Large earlobe
Fleshy earlobe
Fleshy earlobes
Prominent ear lobes
prominent ear lobules
[ more ]
0009748
Large face
Big face
0100729
Low-set, posteriorly rotated ears 0000368
Poor suck
Poor sucking
0002033
Renal insufficiency
Renal failure
Renal failure in adulthood
[ more ]
0000083
Percent of people who have these symptoms is not available through HPO
Achilles tendon contracture
Shortening of the achilles tendon
Tight achilles tendon
[ more ]
0001771
Anteverted nares
Nasal tip, upturned
Upturned nasal tip
Upturned nose
Upturned nostrils
[ more ]
0000463
Arnold-Chiari type I malformation 0007099
Arrhythmia
Abnormal heart rate
Heart rhythm disorders
Irregular heart beat
Irregular heartbeat
[ more ]
0011675
Atrial septal defect
An opening in the wall separating the top two chambers of the heart
Hole in heart wall separating two upper heart chambers
[ more ]
0001631
Autosomal dominant inheritance 0000006
Barrel-shaped chest
Barrel chest
0001552
Bladder carcinoma 0002862
Bronchomalacia 0002780
Cerebral atrophy
Degeneration of cerebrum
0002059
Curly hair 0002212
Deep palmar crease
Deep palm line
0006191
Deep plantar creases
Deep wrinkles in soles of feet
0001869
Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
0000494
Enlarged cerebellum 0012081
Failure to thrive
Faltering weight
Weight faltering
[ more ]
0001508
Fragile nails
Brittle nails
0001808
Global developmental delay 0001263
High palate
Elevated palate
Increased palatal height
[ more ]
0000218
Hoarse voice
Hoarseness
Husky voice
[ more ]
0001609
Hydrocephalus
Too much cerebrospinal fluid in the brain
0000238
Hyperextensibility of the finger joints
Finger joint hyperextensibility
Hyperextensible digits
Hyperextensible finger
[ more ]
0001187
Hyperpigmentation of the skin
Patchy darkened skin
0000953
Hypertelorism
Wide-set eyes
Widely spaced eyes
[ more ]
0000316
Hypoglycemia
Low blood sugar
0001943
Limited elbow movement
Decreased elbow mobility
Limited elbow mobility
Restricted elbow motion
[ more ]
0002996
Low-set ears
Low set ears
Lowset ears
[ more ]
0000369
Lymphangiectasis 0031842
Micrognathia
Little lower jaw
Small jaw
Small lower jaw
[ more ]
0000347
Nevus
Mole
0003764
Obstructive sleep apnea 0002870
Overgrowth
General overgrowth
0001548
Pectus carinatum
Pigeon chest
0000768
Pneumothorax
Collapsed lung
0002107
Pointed chin
Pointy chin
Small pointed chin
Witch's chin
[ more ]
0000307
Posteriorly rotated ears
Ears rotated toward back of head
0000358
Premature birth
Premature delivery of affected infants
Preterm delivery
[ more ]
0001622
Ptosis
Drooping upper eyelid
0000508
Pyloric stenosis 0002021
Redundant neck skin
Excess neck skin
Excess skin over the neck
Redundant skin folds of neck
Redundant skin over the neck
[ more ]
0005989
Respiratory failure 0002878
Respiratory insufficiency
Respiratory impairment
0002093
Rhabdomyosarcoma 0002859
Sparse hair 0008070
Sporadic
No previous family history
0003745
Sudden death 0001699
Talipes equinovarus
Club feet
Club foot
Clubfeet
Clubfoot
[ more ]
0001762
Thin nail
Thin nails
0001816
Tracheomalacia
Floppy windpipe
0002779
Ventriculomegaly 0002119
Vestibular Schwannoma 0009588
Webbed neck
Neck webbing
0000465
Wide anterior fontanel
Wider-than-typical soft spot of skull
0000260
Showing of 98 |
Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Costello syndrome shows significant clinical overlap with Noonan syndrome and cardiofaciocutaneous syndrome, which are also RASopathies. Other disorders to consider include Beckwith-Wiedemann, Noonan syndrome with multiple lentigines (formerly known as LEOPARD syndrome) and Simpson-Golabi-Behmel syndromes.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • Genetics Home Reference (GHR) contains information on Costello syndrome. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Costello syndrome. Click on the link to view a sample search on this topic.

News

Other Conferences

  • Neurofibromatoses and RASopathies: Their Management, Diagnosis, Current and Future Therapeutic Avenues
    Monday, September 30, 2013 - Tuesday, October 01, 2013
    Location: Radisson Blu Hotel, Cardiff, Wales
    Description: This international meeting will provide a most comprehensive and up to date account of recent developments in this field. Internationally recognized experts from the UK, Europe and the USA will speak on neurofibromatoses and rasopathies. This meeting will be suitable for medical geneticists, oncologists, dermatologists, neurologists, endocrinologists, psychiatrists, molecular and cellular biologists, genetic counsellors and general practitioners.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Costello syndrome. Genetics Home Reference (GHR). July 2012; http://ghr.nlm.nih.gov/condition/costello-syndrome.
  2. Costello Syndrome. NORD. 2014; http://rarediseases.org/rare-diseases/costello-syndrome/.
  3. Gripp KW & Lin AE. Costello Syndrome. GeneReviews. January 2012; http://www.ncbi.nlm.nih.gov/books/NBK1507/.