One of Two Major Forms of a Human Condition Called

Multiple Choice

One of two major forms of a human condition called neurofibromatosis (NF1) is inherited as a dominant gene, although it may range from mildly to very severely expressed. Which of the following is the best explanation for why a young, affected child is the first in her family to be diagnosed?

A) The mother carries the gene but does not express it.
B) One of the parents has a mild expression of the gene.
C) The condition skipped a generation in the family.
D) The child has one more chromosome than either of the parents.