Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

 
 
 

Health Articles & Symptom Checker

Search Health Information   
 

Noonan syndrome

Definition

Noonan syndrome is a disease that can be passed down through families (inherited). It causes abnormal development in many parts of the body. Noonan syndrome used to be called Turner-like syndrome.

Causes, incidence, and risk factors

Noonan syndrome is linked to defects in several genes. Problems with the genes cause certain proteins involved in growth and development to become overactive.

Noonan syndrome is an autosomal dominant condition. This means only one parent has to pass down the faulty gene for the baby to have the syndrome. However, some cases may not be inherited.

Symptoms

  • Delayed puberty
  • Down-slanting or wide-set eyes
  • Hearing loss (varies)
  • Low-set or abnormally shaped ears
  • Mild intellectual disability (only in about 25% of cases)
  • Sagging eyelids (ptosis)
  • Short stature
  • Small penis
  • Undescended testicles
  • Unusual chest shape (usually a sunken chest called pectus excavatum)
  • Webbed and short-appearing neck

Signs and tests

The health care provider will perform a physical exam. This may show signs of congenital heart disease (especially pulmonary stenosis, occasionally ASD).

Tests depend on the symptoms, but may include:

  • Platelet count
  • Blood clotting factor test
  • EKG, chest x-ray, or echocardiogram
  • Hearing tests

Genetic testing can help diagnose this syndrome.

Treatment

There is no specific treatment. Your doctor will suggest treatment to relieve or manage symptoms. Growth hormone has been used successfully to treat short stature in some persons with Noonan syndrome.

Support Groups

The Noonan Syndrome Support Group, Inc. -- www.noonansyndrome.org

Complications

  • Buildup of fluid in tissues of body (lymphedema, cystic hygroma)
  • Failure to thrive in infants
  • Low self-esteem
  • Male infertility in those with both testes undescended
  • Problems with the structure of the heart
  • Short stature
  • Social difficulties related to physical symptoms

Calling your health care provider

This condition may be detected on early infant exams. Evaluation by an experienced geneticist is often needed to diagnose Noonan syndrome.

Prevention

Couples with a family history of Noonan syndrome may want to consider genetic counseling before having children.

References

Rapaport R. Hypofunction of the ovaries. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 587.


Review Date: 4/16/2012
Reviewed By: A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by Chad Haldeman-Englert, MD, Wake Forest University School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network (8/4/2011).
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com
 
 
 
St. Joseph's Hospital-North - 4211 Van Dyke Road - Lutz, FL 33558 - (813) 443-7000

Serving The Tampa Bay Area © Copyright 2014 | BayCare Health System