Formerly the neurofibromatoses were grouped as one disorder with at least two variations. Scientists now know that NF1 and NF2 are two distinct entities because the genes believed to be responsible for them are located on different chromosomes. The NF1 gene is on chromosome 17, while the gene for NF2 is on chromosome 22. Humans have 23 pairs of chromosomes, receiving one set of 23 chromosomes from each parent. Chromosomes carry genes that determine an individual's characteristics, such as sex, stature, hair and eye color, and distinctive family traits.
Genes produce proteins that control an individual's development and health.
If an inherited gene is defective, or a gene becomes defective spontaneously before birth, a genetic disorder may result. The neurofibromatoses are inherited as dominant disorders, which means that if either parent has the defective gene, each child born to that parent has a 50 percent chance of inheriting the defective gene. The Institute sponsors basic studies aimed at understanding normal and abnormal development of the brain and nervous system, and clinical studies to improve diagnosis and treatment of neurological disorders. The NF1 gene has been cloned and its structure analyzed. The product of the NF1 gene is a large and complex protein called neurofibromin.