Question 1

Which of the following correctly describes the standardized nomenclature for a missense mutation at nucleotide 67, where adenine is replaced by thymine, resulting in an alanine to threonine change at position 67 of the protein?

Accepted Answer

c.67A\u003eT; p.(Ala67Thr)

Question 2

A patient is found to have a variant described as c.431G\u003eT in the FH gene. What is the corresponding protein change, and what type of mutation is this?

Accepted Answer

p.(Gly144Val); missense mutation

Question 3

According to the HGVS nomenclature, how would you describe a deletion of nucleotides 76 to 78 in a coding DNA sequence?

Accepted Answer

c.76_78del

Question 4

Which of the following best describes the effect of a frameshift mutation caused by the duplication of a guanine nucleotide, resulting in a premature stop codon?

Accepted Answer

The reading frame is altered, leading to a truncated, non-functional protein due to a premature stop codon.

Question 5

A variant described as p.Arg196* is classified as which type of mutation?

Accepted Answer

Nonsense mutation

Question 6

Which of the following best explains the mechanism of nonsense-mediated mRNA decay (NMD)?

Accepted Answer

NMD detects and degrades mRNA transcripts containing premature termination codons, preventing the production of truncated proteins.

Question 7

Which of the following is a correct description of a duplication mutation at position 76 in a coding DNA sequence?

Accepted Answer

c.76dupT

Question 8

A patient has a variant described as c.485_488del. What is the expected protein change and variant type?

Accepted Answer

p.Ile162Thrfs*7; frameshift mutation

Question 9

Which of the following best describes the effect of a silent mutation at the protein level?

Accepted Answer

The amino acid sequence remains unchanged, but the DNA sequence is altered.

Question 10

Which of the following is the correct nomenclature for a substitution mutation where cytosine at position 76 is replaced by adenine in the coding DNA sequence?

Accepted Answer

c.76C\u003eA

Question 11

A variant described as c.77+1G is located at which position within the gene?

Accepted Answer

The first nucleotide of the intron immediately after exon position 77.

Question 12

Which of the following best describes the outcome of exon skipping due to a splicing error?

Accepted Answer

The resulting mRNA lacks the skipped exon, potentially leading to a dysfunctional protein.

Question 13

Which codon is universally recognized as the translation start codon in eukaryotic genes?

Accepted Answer

$$	ext{AUG}$$

Question 14

Which of the following is NOT a possible outcome of a point mutation at the DNA level?

Accepted Answer

Frameshift mutation

Question 15

A variant described as c.76_77insT represents which type of mutation?

Accepted Answer

Insertion of a thymine nucleotide between positions 76 and 77

Question 16

Which of the following best describes the consensus sequence for the 5' splice donor site in eukaryotic genes?

Accepted Answer

$$	ext{AG|GUAAGU}$$

Question 17

Which of the following is a key criterion used in the classification of sequence variants?

Accepted Answer

Evolutionary conservation of the affected amino acid

Question 18

A variant described as p.Gln192= is classified as which type of mutation?

Accepted Answer

Silent mutation

Question 19

Which of the following best describes the effect of a nonsense mutation at the protein level?

Accepted Answer

A premature stop codon is introduced, resulting in a truncated protein.

Genetic Variation Nomenclature, Mutation Types, and Mendelian Inheritance: A Study Guide

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