What is Neurofibromatosis?
Neurofibromatosis (NF) is a neurocutaneous disorder – involving the skin, brain, and several other organ systems. It is the most common single-gene disorder in human beings. It affects 1 in every 2,500 to 3,000 people born worldwide.
What causes Neurofibromatosis?
The cause of NF is a change in a gene that produces a protein called Neurofibromin. This protein has several functions in the body, which include:
- Preventing cells from multiplying too rapidly
- Transmission of nerve signals from the brain to the muscles, processing, and storage of information in the brain
How do you get Neurofibromatosis?
- NF can pass from a parent to the child
- Sometimes, either parent is unaffected and a random genetic change may happen while the baby is in the womb
- Signs are often noticeable at birth or shortly afterward, and almost always by the age of 10
- NF is not contagious – it does not spread on contact
- It does not occur due to drug, alcohol intake or X-ray exposure during pregnancy
NF does not just involve the nerves and skin. Other systems are involved too:
- Flat, light brown spots on the skin (café au lait spots). These harmless spots are common in many people. Having more than six café au lait spots is a strong indication of NF. They are usually present at birth or appear during the first years of life. After early childhood, new spots stop appearing.
- Freckling in the armpits or groin area. Freckling usually appears by ages 3 to 5. Freckles are smaller than café au lait spots and tend to occur in clusters in skin folds.
- Bone deformities. Abnormal bone growth and a deficiency in bone mineral density can cause bone deformities such as a curved spine (Scoliosis) or a bowed lower leg.
- A tumor on the optic nerve (Optic glioma). These tumors usually appear by the age of 3, rarely in late childhood and adolescence, and almost never in adults.
- Tiny bumps on the iris of the eye (Lisch nodules). These harmless nodules can’t easily be seen and don’t affect vision.
- Soft, pea-sized bumps on or under the skin (Neurofibromas). These benign tumors usually develop in or under the skin, but can also grow inside the body. Sometimes, growth shall involve multiple nerves (Plexiform Neurofibroma). Plexiform neurofibromas, when located on the face, can cause disfigurement. Neurofibromas may increase with age.
How is it diagnosed?
Before birth: Antenatal diagnosis is very rare. Ultrasound signs are non-specific; certain tumors associated with NF may be picked up.
After birth: There are no specific tests – the diagnosis is made after a clinical exam. To confirm the diagnosis, your doctor may advise a blood test to look for changes in the NF gene.
Neurofibromas – These are the most striking feature of NF. Neurofibromas are of three types:
- Cutaneous – most common, they look like little bumps, sometimes purplish in colour
- Subcutaneous – swelling felt under the skin, may cause tingling or pain
- Plexiform – grows along a nerve, may involve multiple nerve branches, and cause neurological problems. Risk of turning malignant is 8-13%
Frequently Asked Questions:
Q: My child has NF? So, what next?
A: Most children have mild-moderate symptoms, some are severe. It is difficult to predict the progression of symptoms, each child is different. Regular doctor visits are recommended.
Q: My child was born with 2 café au lait patches. Should I worry?
A: One or two café au lait patches occur in 10% of the general population. Café au lait spots may be part of several other conditions. However, in the absence of any other symptoms or signs, chances are these are benign in nature and do not need a follow-up with your doctor.
Significance of 3-5 café au lait patches: Children with 3–5 café au lait patches but no other signs of NF should be followed up in a Specialist Neurofibromatosis clinic as they might have mosaic NF1 or NF2.
Q: What is the life expectancy of children with NF?
A: Life expectancy is normal, in the absence of complications such as tumors. Generally, children with NF have an IQ in the low average range. In addition, a learning disorder or behavioural concerns may be a concern. Guidance and intervention regarding schooling, activities that can maximize your child’s potential is important.
Q: What to do if my child is born with NF?
A: NF is a condition that has the potential to involve several parts of the body. Children with NF generally need assessments by different specialist doctors. Surveillance is important as several features and complications of NF develop at different ages.
Be Positive. Learn as much as you can about NF, it will help you to better manage any problems as your child grows older. Focus on your child’s strengths. With the right support, there is nothing your child can’t achieve.
Assessment of children with Neurofibromatosis:
The following should be recorded at each annual visit –
- Development and progress at school
- Visual symptoms, visual acuity, and fundoscopy until age 7 years (optic pathway glioma*, glaucoma)
- Head circumference (rapid increase might indicate tumor or hydrocephalus)
- Height (abnormal pubertal development)
- Weight (abnormal pubertal development)
- Pubertal development (delayed/precocious puberty due to pituitary/hypothalamic lesion)
- Blood pressure (consider renal artery stenosis, pheochromocytoma)
- Cardiovascular examination (congenital heart disease, especially pulmonary stenosis)
- Evaluation of the spine (scoliosis ± underlying plexiform neurofibromas)
- Evaluation of the skin (cutaneous, subcutaneous and plexiform neurofibromas)
- System examination if specific symptoms
*Asymptomatic children should also have one baseline assessment of colour vision and visual fields at the appropriate developmental age.
Doctors you may need to consult for children with Neurofibromatosis:
- Neuro and Spine Surgeon
- Orthopaedic Surgeon
- Developmental Paediatrician
- General Paediatrician
- Plastic Surgeon
- Dental Surgeon
References: 1. Malignant peripheral nerve sheath tumours in neurofibromatosis 1. Evans DG et al. J Med Genet. 2002 May; 39(5):311-4. 2. Guidelines for the diagnosis and management of individuals with neurofibromatosis 1.Rosalie E Ferner et al. J Med Genet 2007 Feb; 44(2): 81–88.