What is neurofibromatosis?
Neurofibromatosis, or NF, is a genetic disorder of the nervous system that causes tumors to form throughout the body. It is progressive and is one of the most common genetic diseases in the United States. It is also associated with serious skeletal manifestations and is, therefore, an important condition treated by orthopaedic specialists.
The skeletal complications include compression of the spinal cord, deformities of the spine (scoliosis and kyphosis) and fracture of the tibia (the larger of the 2 lower leg bones) which does not heal. This fracture is called a tibia pseudoarthrosis.
Types of neurofibromatosis
There are two genetically distinct forms of neurofibromatosis.
- The gene for NF-1 is more commonly affected and is located on chromosome 17. It is known as “peripheral neurofibromatosis.”
- The gene for NF-2 is less commonly affected and is located on chromosome 22. It is called “central neurofibromatosis” because it tends to affect parts of the body not readily seen. The rest of this guide will refer specifically to neurofibromatosis type 1.
What are the signs and symptoms of neurofibromatosis?
NF type 1 affects about 1 in every 3000 newborn babies. There are many signs and symptoms. Doctors have come up with ways to rank their importance to be able to make more reliable diagnoses.
A child may have “café-au-lait” spots which are coffee-colored marks on the skin measuring about 5 mm on average. Freckling in the armpit or groin area is also common. Other tumors may develop: optic nerve glioma (a tumor of the main nerve to the eye), Lisch nodules (tumors of the iris which is the colored part of the eye), and bone lesions such as thinning or fracture of the tibia.
Other more rare signs include kyphoscoliosis, a difference in leg lengths, elephantiasis, mental retardation, and high blood pressure.
What are the risk factors of neurofibromatosis?
Having a family member with NF-1
There are indications for both medical and surgical care in NF. Care should be coordinated by and expert in genetics.
When a tibia deformity is present from birth, a brace is commonly used to protect against fracture. If the tibia fractures, surgery is typically necessary. The most common surgical procedure involves placing a rod down the middle of the tibia and then using bone graft to support healing.
When scoliosis or kyphosis develops, a brace for the spine is offered to growing children. The goal of the brace is to prevent the worsening of the spinal deformity. More severe scoliosis or kyphosis may require surgery, a posterior spinal fusion with instrumentation.