nbme24/Block 2/Question#42
A 3-week-old female newborn is brought to the ...
The patient has another mutation that was not included in the previous analysis
charcot_bouchard
OR another allele has a diff type of mutation because CF is done by like hundreds of diff type of mutation. SO the 70 types that we screened covered one type from one parent but not another that was inherited from other parent.
+4 2019-06-26T04:54:18Z
soph
I put D thinking there was a mutation in another protein that interacts with CFTR....thus u dont have CF but some disease with similar phenotype. Is this wrong bc its simply not the case ??
+ 2019-07-29T02:09:26Z
nbmehelp
@charcot_bouchard I think that makes more sense if I understand what you're saying- Probably had a mutation only in 1 of 2 of the same alleles in the analysis but had another mutation in 2 of 2 alleles at a different location not included in the analysis, right?
+ 2019-07-29T19:45:34Z
submitted by colonelred_(43), 2019-05-20T10:46:13Z
The analysis only showed a mutation in one allele. CF is an autosomal recessive disease: the disease only manifests if there are mutations in both alleles of the CFTR gene.
If you still have 1 functional copy of the CFTR gene, you can still make the CFTR protein (the chloride channel/transporter), hence your body won’t have any issues.
This is analogous to tumor suppressor genes like Rb: so long as one of the alleles you have is functional, you can make enough of the protein to “make up” for the defective allele. If both get knocked out (Rb-/-), you lose the protection provided by the gene because now you make no protein at all.
The only thing that made sense for this question was the fact that the other allele was not included in the analysis.