Final answer:
Neurofibromatosis-causing mutations inherited from affected parents are likely to be loss-of-function mutations. These mutations result in the loss or decreased function of the neurofibromin protein. The inheritance pattern of neurofibromatosis follows an autosomal dominant pattern, with a 50% chance of inheriting the disease allele.
Step-by-step explanation:
Neurofibromatosis type 1 (NF1) is a genetic disorder caused by mutations in the NF1 gene. When the mutations in the NF1 gene are inherited by affected children from affected parents, they are most likely to be loss-of-function mutations.
Loss-of-function mutations result in a decreased or complete loss of the protein's function. In the case of NF1, these mutations lead to the loss of a protein called neurofibromin, which plays a crucial role in regulating cell growth and division.
To understand the inheritance of NF1, we can look at the Punnett square. When one parent is heterozygous for NF1 and the other parent is homozygous for the normal gene, there are four possible genotypes for the offspring: Nn, Nn, nn, and nn. The Nn genotype represents individuals with neurofibromatosis, while the nn genotype represents individuals without the disease.
Therefore, the likelihood of inheriting neurofibromatosis is 50% for every child of this couple. This inheritance pattern follows an autosomal dominant pattern, where the presence of a single copy of the disease-causing allele (N) is sufficient to cause the disease.