Question

Review the Allelic Variants starting with .001, how does the information in brackets describe the mutation?

Example: [CFTR, PHE508DEL] For each mutation (allelic variant) listed below, explain how the mutation would affect the production of: (20 pts total/4 pts each) the mRNA the protein encoded by the CFTR gene.

Example: .0001 CYSTIC FIBROSIS [CFTR, PHE508DEL] The 508th triplet codon, which normally codes for phenylalanine, is deleted. Consequently, the CFTR mRNA is 3 nucleotides shorter than normal, and the CFTR protein is one amino acid shorter, missing its 508th unit.

.0003 CYSTIC FIBROSIS [CFTR, GLN493TER]

.0004 CYSTIC FIBROSIS [CFTR, ASP110HIS] .

0019 CYSTIC FIBROSIS [CFTR, 2-BP INS, 2566AT] .

0008 CYSTIC FIBROSIS [CFTR, IVS10, G-A, -1] .

0064 CYSTIC FIBROSIS [CFTR, IVS12, G-A, +1]

.0123 CYSTIC FIBROSIS [CFTR, 21-KB DEL]

Sarah and Michael looked confused. “But….” Michael started to say. “How can the test say I’m not a carrier, but you say that I could still be a carrier?” Sarah finished. The counselor explained, “Because the gene for CF has over 1400 known genetic changes it is difficult to design a test that can detect all of the changes and the test remain cost effective. The test that you had tested you for the most common CF mutations that are seen. This testing can identify the majority of carriers. However, individuals with a negative test will still chance to be a carrier. The chance is greatly reduced, but not zero.”

Using the table below, what is the chance that Sarah is actually a carrier for a CFTR mutation, even though her carrier test results came back negative?

Racial or Ethnic Group Detection rate of Carrier Testing (%)

Ashkenazi Jewish 94

Non-Hispanic Caucasian 88

Hispanic American 72

African American 65

Asian American 49

Answer 1