There are specific diagnostic criteria for NF1, NF2 and Schwannomatosis. These criteria have been laid out by the National Institute of Health (NIH) Consensus Development Conference Statement 1988. Along with the features required for diagnosis there are other features and complications associated with the conditions. Both the diagnostic criteria and additional features/complications are outlined below for each condition.
It is important to be aware of the possible features and complications of the condition that affects you, your child, family member, friend or someone in your community as the conditions vary a great deal.
To receive a diagnosis of NF1 according to the NIH statement a person must have at least 2 of the following:
- A first degree relative with NF1
- Six or more café au lait patches (brown “birth marks) >0.5 cm in children and >1.5 cm in adults
- Axillary (armpit) or groin freckling
- 2 or more neurofibromas (pea sized lumps on the skin) of any type OR 1 plexiform neurofibroma (larger areas on the skin that appear swollen)
- 2 or more Lisch nodules (benign pigmented tumours also known as iris hamartomas)
- Optic pathway glioma
- Bony dysplasia (enlargement) of the sphenoid wing (part of a bone in the skull) or
- Thinning of the long bone cortex (one of the three layers of bone) with or without pseudoarthrosis (a false joint caused through naturally unmendable fracture) of the long bones.
Along with the features required for diagnosis there are other features and complications that may arise for a person with NF1:
- Scoliosis – curvature of the spine
- Learning disabilities
- Large head
- Early or late onset of puberty
- Short stature
- High blood pressure (can be caused by a narrowing in the arteries to the kidneys and occasionally due to a tumour in the adrenal glands
- Somewhat increased risk for rare malignancies occurring in the brain, nerves or spinal cord compared with the general population
- Brain tumours
- Stroke (cerebrovascular occlusion)
- Itchy skin
To receive a diagnosis of NF2 according to the NIH statement a person must have:
There are now also alternative diagnostic criteria for NF2, The Manchester diagnostic criteria takes into account people who do not have a family history of NF2:
Because Schwannomatosis is rare and the genetic cause of the condition remains unknown the diagnostic criteria for this condition are still up for consideration. However, in 2005 researchers based at the Massachusetts General Hospital published diagnostic criteria based upon what is currently known.
Possible additional diagnostic criteria: