Noonan syndrome

People with Noonan syndrome grow to between 155 cm (women) to 165 cm (men). The condition is thought to affect between 1 in 1,000 to 1 in 5,000. Noonan syndrome is also called the pseudo-Turner syndrome.

Although children with Noonan syndrome are short, they are not generally as short as other children with growth disorders and their height sits on the lower end of the growth curves, when viewed on a growth chart


This syndrome can be caused by a problem with one of the genes involved in growth. 

Signs and Symptoms

  • Short height.
  • Large eyes that are set wide apart. 
  • Low set ears.
  • Short neck.
  • Low hairline across the neck.
  • Vision problems: crossed eyes, squinting. Children often need glasses.
  • Heart defect – this is usually discovered during pregnancy. May need medication and/or surgery.
  • Low birth weight.
  • Bleeding – children are more likely to bleed following an injury and may bruise more easily.
  • Feeding problems - the child may not eat well and has little interest in food.​
  • Low strength - the muscles and joints are not very strong and the child has problems moving around. 
  • Testicles – in the majority of boys, surgery will be required to make the testicles descend into the scrotum
  • Delayed puberty.


This condition is complex  so a mutlidisciplinary approach will be needed to treat the different symptoms. If your child's growth hormone levels are insufficient, growth hormone may be a treatment option.

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