Table 1 Characteristics of chromoanagenesis classes

Mutational event

Single

Single or multiple

Single or multiple

Chromosomes

Few (1–4)

Few (usually 1)

Many (usually ≥ 4)

Breakpoints

Many (≥5; sometimes > 25)

Fewer (usually 5–25)

Fewer (usually 5–25)

Breakpoint distribution

Clustered

Clustered

Interspersed (usually in active chromatin)

Breakpoint signature

Blunt ends

Microhomology

Blunt ends

Dosage alteration

Cancer: often unbalanced (deletion bridges); Germline: mainly balanced (<5% of total rearrangement)

Unbalanced (predominantly copy gain)

Mainly balanced (occasional deletion bridges)

Proposed mechanism

Micronucleus missegregation + chromosome pulverization + NHEJ

Micronucleus missegregation + chromosome pulverization + MMBIR/FoSTeS

Multiple DSBs during active transcription + NHEJ

Proposed parent-of-origin bias

Paternal

None

None

Proposed transmission bias

Maternal

None

None

Germline reports

43

10

6

Case:Control

39:4

10:0

6:0

References

[9, 10, 17, 18, 23, 76–78]

[19–21]

[9, 22, 23]