Can someone please please help me with these two questions!! My answers are in b
ID: 187072 • Letter: C
Question
Can someone please please help me with these two questions!! My answers are in bold, and just need them checked. Thank you to whoever can take the time to help me out.
The following pedigree shows retinitis pigmentosa in a family. Two genes (genotypes are shown for each individual) are responsible for this phenotype. What observations in this pedigree suggests that it is a multigenic disease instead of a single gene inheritance
Every affected individual has an affected parent.
Not all children of affected parents are affected.
When only one gene is mutated, there is no disease phenotype.
There is no clear inheritance pattern traceable.
The late onset form of Alzheimer’s disease is an example of multifactorial traits. Which of the following is NOT a sound piece of advice during genetic counseling of families with patients with this condition?
The recurrence risk is much higher for first-degree relatives of affected family members.
The estimate of recurrence risk is empirical risk, based on past experience.
The calculation of recurrence risk is based on the molecular characterization of the disease, which is well understood.
The recurrence risk is increased by the presence of more than one affected relatives or consanguineous parentage.
A.Every affected individual has an affected parent.
B.Not all children of affected parents are affected.
C.When only one gene is mutated, there is no disease phenotype.
D.There is no clear inheritance pattern traceable.
Genotype: peripherin: + or mut ROM1: +or mut +/mut +/mut +/mut +/mut +/mut +/mut+/mut +mutmut +/mut mut+/mut /mut+ +/mut +/mut +/mut +/mut +/mut +/mut +/mut +/mut +/mut ++ +/mut ++ +I+/mut +Imut +/mut +/mut/mut +1+mut+mut +/mut ++ +mut ++ © Elsevier. Nussbaum et al: Thompson and Thompson's Genetics in Medicine 7e-www.studentconsult.comExplanation / Answer
1.Correct answer would be:C.When only one gene is mutated, there is no disease phenotype.
Reason: Multigenic diseases are result of the interaction between genes from parents as well as environmental factors that affect genes. This means that a multigenic disease those are genetic could also be triggered by environmental factors.In above case, we can see that when one gene is mutated there is no disease and disease occurs only when two genes are mutated.
2.Correct answer would be:C.The calculation of recurrence risk is based on the molecular characterization of the disease, which is well understood.
Reason:Multifactorial traits can recur in families, because they are not totally caused by genes but partly caused by genes. The chance for a multifactorial trait to recur again depends upon how closely the family members having the trait are related to you.So, it is not based on molceular characterization of disease alone.