Hearing and vision

People with Noonan syndrome can suffer from hearing loss and eye problems.


Problems with hearing are relatively common, but in many cases these are related to fluid in the middle ear (chronic otitis media) in childhood and are temporary. Severe hearing problems are rare but may be helped with hearing aids or cochlear implants.


Eye problems that may affect people with Noonan syndrome include:

Strabismus – a condition where the eyes do not point in the same direction. Also known as a squint, the condition causes one or both eyes to turn inward (‘crossed eyes’) or outward (‘wall eyes’).

Refractive errors – a type of visual problem that makes it hard to see clearly. They occur when the shape of the eye keeps light from focusing correctly on the retina (a light-sensitive layer of tissue in the back of the eye). It is corrected by glasses.

Amblyopia – also known as a ‘lazy eye’, amblyopia is a childhood condition where the vision does not develop properly because one or both eyes are unable to build a strong link to the brain. It usually only affects one eye, and means that the child can see less clearly out of the affected eye and relies more on the ‘good’ eye. It is treated by patching the eye.

Nystagmus – a condition of uncontrolled eye movement that causes the eyes to move or “wobble” constantly.


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People with Noonan syndrome show a slight increase in risk of having seizures. These do not seem to have a particularly different pattern from other forms of epilepsy, although there is some evidence of non-epileptic or dissociative seizures occurring.

Epilepsy is a major clinical issue in cardiofaciocutaneous (CFC) syndrome when it is caused by the BRAF gene. Seizures have been estimated to occur in between 15–50% of patients with BRAF mutations, and may be severe and associated with changes on the brain MRI scan. The treatment may involve several anticonvulsants.


We have a son in his 30s who has NS and was born profoundly deaf. Has there been any recent research into connection between the two?

Noonan syndrome with multiple lentignes or freckles (previously known as LEOPARD syndrome) has deafness as a feature and so we know that deafness may be associated with the PTPN11 gene. In most cases deafness in Noonan syndrome will simply be due to glue ear but it may be due to nerve deafness. There has not been much research on the nerve deafness in Noonan syndrome.

Is it common to have an issue with a child regulating his body temperature—starting to go blue after 5 minutes swimming but so hot in bed at night he can hardly be touched?

The issue with body temperature is seen in neurological conditions such as CFC and Costello and sweating seems to be quite common in Noonan Syndrome but it does seem to diminish with age.

Is a child’s auditory neuropathy (hearing loss in which the outer hair cells within the cochlea are present and functional, but sound information is not faithfully transmitted to the auditory nerve and brain properly) a result of having Noonan Syndrome?

Some children with Noonan Syndrome have problems with hearing, most commonly “glue ear”. It’s possible that the child’s condition was linked to Noonan Syndrome but more information was needed. There were genetic tests which should be able to tell if the condition was linked causally. People with Leopard Syndrome, closely related to NS, often suffered hearing problems.