As you will know CMN can be associated with neurological or brain problems in a minority of people.  These brain problems are very variable, and lots of different types of things have been described in different people.  Briefly, these are the things that have been found:

  • The most common finding is melanosis (a bit like moles) in the substance of the brain.  This is usually found on MRI scan, and only around 50% have any symptoms of this. When the melanosis does give symptoms directly, this is usually fits which are usually in the temporal lobe (temporal lobe epilepsy).  However, the other symptom that is associated with seeing melanosis on the scan, but does not seem to be directly caused by the melanosis, is developmental delay.  In other words, the melanosis we can see on scan seems to be a sort of marker for abnormal brain development, rather than being the actual cause.  This is currently being investigated in more detail.
  • Everything else is much rarer, and when these things are present they are usually from birth or soon afterwards, so if children have not been scanned by the age of 2 years old, and are entirely well, they would be very unlikely to have any of these.  These rare things include:
    • Brain tumours (not melanoma), usually benign, but usually need to be removed
    • Hydrocephalus (too much fluid in the brain) – this is caused by melanosis in the coverings of the brain and spine, which is not always visible on scan.  Hydrocephalus always needs treatment with a special operation to shunt the fluid out of the brain and into the abdomen.
    • Malformations of the brain.
  • Melanoma can occur in the brain. This is rare but can occur at any age.

If your child has been diagnosed with any of the above there is dedicated support available.

Hayleigh Crowe can be contacted on

You can read Hayleigh’s story here.