Nomenclature

Question 1

3 types of mutation

Answer 1

Genome mutation (aneuploidy)

Chromosome mutation (translocation, duplication, inversion, deletion)

Gene mutation (SNV, indel)

Question 2

Aneuploidy is more linked to ___ age

Answer 2

Aneuploidy is more linked to maternal age

Due to mitotic spindle arrest

Question 3

SNVs are more linked to ___ age

Answer 3

SNVs are more linked to paternal age
Due to increased germ cell divisions

Question 4

SNP

Answer 4

Single nucleotide polymorphism

By definition, common with a population prevalence of >1%

Question 5

HGVS sequence type specification

Answer 5

Question 6

” > “ in HGSV

Answer 6

Indicates a substitution at the DNA level
ie, c.76A>T

Question 7

” _ “ in HGSV

Answer 7

Indicates a range of affected residues, specifying the first and last affected residue.
ie, c.76_78delACT

Question 8

” del “ in HGSV

Answer 8

Indicates a single nucleotide deletion
ie, c.76delA

Question 9

” dup “ in HGSV

Answer 9

Indicates a duplication.
ie, c.76dupA

Question 10

” ins “ in HGSV

Answer 10

Indicates an insertion, specifying the residues in between where the insertion is located.
ie, c.76_77insG

Question 11

” * “ in HGSV

Answer 11

Indicates a nonsense mutation.
ie, p.Trp26*

Question 12

Combined insertion/deletions in HGSV

Answer 12

g.4_5delinsTG

Describes the replacement of residues 4 and 5 with the nucleotides T and G

Question 13

Translocation involving the centromere

Answer 13

Pericentric

Question 14

Translocation not involving the centromere

Answer 14

Paracentric

Question 15

What gene nomenclature system should you use?

Answer 15

HGNC

So it’s ERBB2, not Her2

Question 16

c.-14A>T

Answer 16

Rarely used, but this refers to an A at position -14 (14 bases prior to the first residue of the start codon) which has been changed to a T.

Question 17

c.*15T>G

Answer 17

Rarely used, but this refers to a T at position +15 (15 bases after the last residue of the stop codon) which has been changed to a G.