Question

Neurofibromatosis type 1 is an inherited fominant disorder. The phenotype usually invovles the production of many skin neurofibromas.

Which of the following events in a normal cell from an individual inheriting a neurofibromatosis-causing allele could cause the descendants of that cell to grow into a neurofibroma?

i. A second mutation in the allele of NF1 inherited from the affected parent
ii. A point mutation in the allele of NF1 inherited from the normal parent
iii. A large deletion that removes the NF1 geen from the chromosome inherited from the affected parent
iv. A large deletion that removes the NF1 gene from the chromosome inherited from the nromal parent.
v. Mitotic chromosomal nondisjunction or chromosome loss.
vi. Mitotic recombination in the region between the NF1 gene and the centromere of the chromosome carrying NF1
vii. Mitotic recombination in the region between the NF1 gene and the telomere of the chromosome carrying NF1

Answer 1

A large deletion that removes the NF1 gene from the chromosome inherited from the affected parent can cause the descendants of a normal cell to grow into a neurofibroma.

Step-by-step explanation:

To cause the descendants of a normal cell from an individual inheriting a neurofibromatosis-causing allele to grow into a neurofibroma, a mutation or event would need to occur that affects the NF1 gene. The NF1 gene is responsible for regulating cell division and growth, and any disruption in its function can lead to tumor formation. Out of the options provided, the event that would most likely cause the descendants of the cell to grow into a neurofibroma is a large deletion that removes the NF1 gene from the chromosome inherited from the affected parent.