Multiple paralogs and recombination mechanisms contribute to the high incidence of 22q11.2 deletion syndrome

Table 2.

22q11.2 LCR rearrangement loci (RL) at nucleotide resolution

Family (deletion) Sequencing technology RL Nucleotide-level rearrangement locus (hg38) Gene content Repeat content
AD004 (LCR22-A/D) SLR, ULR, HDR (ONT) RL-AD1 (160 kb) 319 bp
Chr 22:18,775,948–18,776,026 (A)
Chr 22:21,210,278–21,210,356 (D)
intronic: GGT3P (A)
GGT2 (D)
L2 LINE
AD007 (LCR22-A/D) SLR (ONT) RL-AD1 (160 kb) 421 bp
Chr 22:18,791,335–18,791,756 (A)
Chr 22:21,225,667–21,226,088 (D)
exonic/intronic: GGT3P (A)
GGT2 (D)
L2 LINE
AD008 (LCR22-A/D) ULR (ONT) RL-AD1 (160 kb) 650 bp
Chr 22:18,791,386–18,792,037 (A)
Chr 22:21,225,716–21,226,367 (D)
exonic/intronic: GGT3P (A)
GGT2 (D)
L2 LINE
AB001 (LCR22-A/B) ULR (ONT) RL-B2 (8 kb) AT repeat within 8 kb locus
Chr 22:18,201,246–18,207,385 (A)
Chr 22:20,336,265–20,339,445 (D)
intronic: FAM230D (A)
FAM230G (B)
PATRR
AB002 (LCR22-A/B) ULR (ONT) RL-B2 (8 kb) AT repeat within 8 kb locus
Chr 22:18,201,246–18,207,385 (A)
Chr 22:20,336,265–20,339,445 (D)
intronic: FAM230D (A)
FAM230G (B)
PATRR
AB004 (LCR22-A/B) Long-range PCR and PacBio SMRT sequencing RL-B2 (8 kb) AT repeat within 8 kb locus
Chr 22:18,201,246–18,207,385 (A)
Chr 22:20,336,265–20,339,445 (D)
intronic: FAM230D (A)
FAM230G (B)
PATRR
AC001 (LCR22-A/C) ULR (ONT) RL-C (10 kb) 119 bp
Chr 22:18,855,275–18,855,394 (A)
Chr 22:20,698,426–20,698,545 (C)
AluJo
SINE
AC002 (LCR22-A/C) ULR (ONT) RL-C (10 kb) 866 bp
Chr 22:18,845,968–18,846,834 (A)
Chr 22:20,689,067–20,689,933 (C)
exonic: POM121L15P (A)
POM121L4P (D)
AluS
SINE
BD001 (LCR22-B/D) STR, ULR (ONT) RL-B1 (20 kb) 200 bp
Chr 22:18,187,091–18,187,290 (A)
Chr 22:20,353,454–20,353,653 (B)
intronic: FAM230D (A)
FAM230G (B)
/
CD001 (LCR22-C/D) STR, ULR (ONT) RL-C (10 kb) 200 bp
Chr 22:20,697,310–20,697,507 (C)
Chr 22:21,290,100–21,290,300 (D)
intronic: POM121L8P (D) /
  • The first column shows the family identifier, based on Supplemental Table1, and diagnosed deletion type. The fiber-FISH based (Table 1) as well as the length of the RL is presented in the second column. The third column provides the position of the last proximal-specific SNP and the first distal-specific SNP and the length of the locus. The exact position could not be mapped for the three PATRR-mediated LCR22-A/B deletions due to the presence of several PATRRs in the reference genome. Columns four and five show the gene and repeat content, respectively. Repetitive elements and gene exons/introns can be fully or partly covered in the recombination locus. More information on the exact composition of the recombination locus can be found in Supplemental Fig 3. In family BD001, the deletion is diagnosed as LCR22-B/D; however, the recombination occurred between LCR22-A and -B (corresponding to chromosomal loci in the third column), as explained in Figure 4C.

  • (RL) Recombination locus, (SLR) standard long-read sequencing, (ULR) ultra-long-read sequencing, (HDR) high duplex read sequencing.

This Article

  1. Genome Res. 35: 786-797

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