Long-read genome sequencing and variant reanalysis increase diagnostic yield in neurodevelopmental disorders

Table 2.

Variants identified by long-read sequencing

Proband ID Gene(s) affected HGVS nomenclature Inheritance Variant classification Case-level classification ACMG/ClinGen evidence codes SV, SNV or TRE Step of srGS lossa Orthogonal validation
1 ZBTB20 NC_000003.12:g.110477273_114639202_inv De novo LP Likely Diagnostic 2C(+1.00), 5A (+0.15) SV Filtering/QC Yes, Research Sanger of breakpoints
2 ALS2 NC_000002.12:g.201720435-201725085_del; NC_000002.12:g.200115181-201739349_del Biparental LP; P Definitive Diagnostic 2E (+0.90);2D-4 (+0.90), 3B (+0.45) SVx2 Filtering/QC Pending, supported by srGS data
3 HCFC1 NC_000023.11:g.153948602_ins4902, NM_005334.3:c.*745_ins4902 Maternal (X-linked) VUS Uncertain NA SV Variant calling Yes, Research PCR amplification of breakpoints
4 ABAT, PMM2, USP7, etc. NC_000016.9:g.(8742452_9220783)dup_ins[(8742452_8879961)_(9000190_9220783)] De novo VUS Uncertain 2K (+0.30) SV Variant calling Pending
5 PHOX2B NM_003924.4:c.741_758dup, p.(Ala255_Ala260dup) Unknownb P Definitive Diagnostic PS4_M, PM1_Strong, PM2_Moderate, PM6_Moderateb TRE Variant calling Yes, Clinical testinga
6 AFF3 NM_001386135.1:c.-64-281_-64-280insGGC[90] Unknown VUS Uncertain NA TRE Variant calling Pending
7 SHANK3 NM_033517.1:c.3161delT, p.(Lys1054Argfs*10) De novo P Definitive Diagnostic PVS1_VeryStrong, PS2_Strong, PM2_Moderate SNV Variant calling Yes, Clinical Sanger
8 HNRNPU NM_031844.3:c.660_661dupAGGCGGCGGA, p.(Gly221ArgfsTer25) De novo P Definitive Diagnostic PVS1_VeryStrong, PS2_Strong, PM2_Moderate SNV Curation (gene-disease association) Yes, Clinical Sanger
9 CSNK2B NM_001320.6:c.202C > T, p.(Gln68Ter) Paternal LP Likely Diagnostic PVS1_VeryStrong, PM2_Moderate SNV Curation (gene-disease association) Yes, Clinical Sanger
10 GNB2 NM_005273.4:c.217G > A, p.(Ala73Thr) Maternal LP Uncertain PS4_Moderate, PP2_Supporting, PP3_Supporting SNV Curation (gene-disease association) Yes, Clinical Sanger
11 MCF2 NM_005369.5:c.2234G > T, p.(Gly745Val) Maternal (X-linked) VUS Uncertain PM2 SNV Curation (gene-disease association) Yes, Clinical Sanger
12 NOTCH3 NM_000435.3c.6409_6410delCT, p.(Leu2137GlyfsTer104) Paternal LP Likely Diagnostic PVS1_Strong, PM2_Moderate SNV Curation (unexpected mechanism) Yes, Clinical Sanger
13 AFF4 NM_014423.4, c.879delA, p.(His294IlefsTer5) Paternal VUS Uncertain PM2 SNV Curation (unexpected mechanism) Yes, Clinical Sanger
14 KCNT2, KIF21A NC_000001.11:g.196329420-196344697_DUP, NM_017641.3:c.847C > T, p.(Arg283Cys); NM_017641.3:c.706C > T, p.(Gln236Ter) Paternal/biparental VUS, VUS;LP Uncertain 2I (+0.45); PM2, PP3; PVS1, PM2 SV; SNV(x2) Curation (unexpected mechanism) SV Pending, supported by srGS data; SNVs-Clinical Sanger
15 NRXN1 NC_000002.12:49922063_49928691del De novo VUS Uncertain 2E (+0.30), 4C (+0.15), 4M (+0.30) SV Curation (unexpected mechanism) Pending, supported by srGS data
16 SCN1A NM_001165963.4:c.4003-603T > C Paternal VUS Uncertain PM2_Moderate SNV Curation (noncoding variation) Yes, Clinical Sanger
  • (SV) Structural variant, (SNV) single nucleotide variant, (TRE) tandem repeat expansion, (P) pathogenic, (LP) likely pathogenic, (VUS) variant of uncertain significance, (NA) not applicable.

  • aFiltering/QC, our filtering or prioritization strategy did not accurately present this for curation (or did not at all); Variant calling, the variant was not called or was called incorrectly/inaccurately; Curation, manual curation did not result in flagging of the variant(s).

  • bIndependent clinical testing indicated that the PHOX2B expansion was de novo; we only sequenced the proband in our research study.

This Article

  1. Genome Res. 34: 1747-1762

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