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Noonan Syndrome

Noonan syndrome is named for Dr. Jacqueline Noonan, a pediatric cardiologist, who first identified it in 1963. Noonan syndrome is caused by a genetic mutation that may cause congenital heart disease, distinctive facial features, short stature, and other conditions.

Well, what does it mean if the doctor says that your child has short stature caused by Noonan syndrome? It means that your child is shorter than average for his or her age group due to a rare genetic disorder that may affect growth.

Noonan syndrome may present as short stature in up to 83% of patients. Features appear at birth or during early childhood. Boys and girls are affected equally. It is estimated that 1 in 1,000 to 2,500 infants are born with Noonan syndrome.

If your child is shorter than average, he or she may be seen by an endocrinologist. This doctor is a specialist who is trained to diagnose and treat children with growth disorders. The endocrinologist will evaluate your child to find the cause of your child’s short stature.

Features of Noonan syndrome

Some of the common physical traits and conditions of Noonan syndrome are:

  • Short stature
  • Heart defects
  • Increased bruising or bleeding
  • Unusual facial features
    • Wide-set eyes
    • Arched eyebrows
    • Down-slanting eyes
    • Low-set ears with forward-facing lobes
    • Drooping eyelids
  • Delay in puberty
  • Poor eyesight
  • Chest and skeletal deformities
  • Webbed neck
  • A low hairline at the back of the neck
  • Learning disability or mild retardation
  • Lymphatic abnormalities
  • Undescended testicles in males at birth
  • Poor weight gain in infancy
  • Brilliant blue or blue-green eyes
  • Feeding difficulties
  • Frequent or forceful vomiting
  • Hearing problems
  • Poor muscle tone in early development

Some children may have many of these features, while others have just a few.

As children grow older, facial signs of Noonan syndrome may begin to fade.

Short stature is one of the main features of Noonan syndrome. It affects up to 83% of children diagnosed. In children with Noonan syndrome, puberty can be delayed by about 2 years. The pubertal growth spurt is often reduced or absent. Bone development is also delayed by 2 years.

The average final height for patients with Noonan syndrome is generally less than the normal population.