At the time of his birth, BG was noted to have large brown spots over his abdomen and upper thighs. In the nursery, the pediatrician raises with the parents the possibility that their child may have neurofibromatosis type 1. Before any formal genetic counseling, they quickly go to their nearby library, and using a series of medical reference books, learn to their horror that neurofibromatosis type 1 is a serious, disfiguring genetic disorder associated with a propensity to develop various forms of life-threatening cancers. Attending a multidisciplinary clinic that evaluates children and adults for neurofibromatosis, the staff, including a medical geneticist and a dermatologist, reaffirm their pediatrican's initial concern and attempt to provide detailed medical information to the parents about the potential clinical effects of neurofibromatosis type 1. The parents' focus, however, is on the association of neurofibromatosis type 1 with cancer.
Neurofibromatosis is one of the most common autosomal dominant disorders in humans.
Neurofibromatosis Type 1 is by far the more common form of neurofibromatosis, with an incidence at birth of approximately 1 in 3,000, regardless of ethnic background. However, expressivity is extremely variable, with affected members in the same family showing wide differences in clinical symptoms. Approximately half of all cases of neurofibromatosis type 1 are due to new mutations and the family history is negative. The mutation rate is estimated to be 1 in 10,000 gametes, one of the highest known mutation rates in humans. Other alternatives, although less likely, do exist and require further investigation.