13-108210436-C-G

Variant names:

• chr13-108210436-C-G
• rs104894421
• NM_206937.2:c.833G>C

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_206937.2(LIG4):​c.833G>C​(p.Arg278Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000548 in 1,461,002 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R278S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: LIG4 NM_206937.2 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.50
• Publications: 1 publications found

Genes affected

LIG4 (HGNC:6601): (DNA ligase 4) The protein encoded by this gene is a DNA ligase that joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction. This protein is essential for V(D)J recombination and DNA double-strand break (DSB) repair through nonhomologous end joining (NHEJ). This protein forms a complex with the X-ray repair cross complementing protein 4 (XRCC4), and further interacts with the DNA-dependent protein kinase (DNA-PK). Both XRCC4 and DNA-PK are known to be required for NHEJ. The crystal structure of the complex formed by this protein and XRCC4 has been resolved. Defects in this gene are the cause of LIG4 syndrome. Alternatively spliced transcript variants encoding the same protein have been observed. [provided by RefSeq, Jul 2008]

LIG4 Gene-Disease associations (from GenCC):

• DNA ligase IV deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Orphanet, G2P
• Dubowitz syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Omenn syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_206937.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-108210437-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2784298.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983
• PP5: Variant 13-108210436-C-G is Pathogenic according to our data. Variant chr13-108210436-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2736057.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LIG4	NM_206937.2	c.833G>C	p.Arg278Pro	missense_variant	Exon 3 of 3	ENST00000442234.6	NP_996820.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LIG4	ENST00000442234.6	c.833G>C	p.Arg278Pro	missense_variant	Exon 3 of 3	1	NM_206937.2	ENSP00000402030.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000548 AC: 8 AN: 1461002 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 726748

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39680

South Asian (SAS) AF: 0.00 AC: 0 AN: 86238

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52872

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000720 AC: 8 AN: 1111764

Other (OTH) AF: 0.00 AC: 0 AN: 60372

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

DNA ligase IV deficiency Pathogenic:1

Jun 20, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Arg278 amino acid residue in LIG4. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 26762768). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt LIG4 protein function. This missense change has been observed in individual(s) with atypical severe combined immunodeficiency (PMID: 21664875). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 278 of the LIG4 protein (p.Arg278Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D;D;D;D;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	.;.;.;D;D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.2	H;H;H;H;.
PhyloP100		7.5
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-7.0	D;.;D;D;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;.;D;D;.
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	D;D;D;D;.
Vest4		0.99
MutPred		0.85		Gain of catalytic residue at K273 (P = 0.034);Gain of catalytic residue at K273 (P = 0.034);Gain of catalytic residue at K273 (P = 0.034);Gain of catalytic residue at K273 (P = 0.034);.;
MVP		0.93
MPC		0.39
ClinPred		1.0	D
GERP RS		5.5
Varity_R		1.0
gMVP		0.97
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs104894421; hg19: chr13-108862784;