19-12806747-G-T

Variant names:

• chr19-12806747-G-T
• rs955631391
• NM_006397.3:c.74G>T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_006397.3(RNASEH2A):​c.74G>T​(p.Arg25Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000141 in 1,420,070 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. R25R) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: RNASEH2A NM_006397.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.322

Genes affected

RNASEH2A (HGNC:18518): (ribonuclease H2 subunit A) The protein encoded by this gene is a component of the heterotrimeric type II ribonuclease H enzyme (RNAseH2). RNAseH2 is the major source of ribonuclease H activity in mammalian cells and endonucleolytically cleaves ribonucleotides. It is predicted to remove Okazaki fragment RNA primers during lagging strand DNA synthesis and to excise single ribonucleotides from DNA-DNA duplexes. Mutations in this gene cause Aicardi-Goutieres Syndrome (AGS), a an autosomal recessive neurological disorder characterized by progressive microcephaly and psychomotor retardation, intracranial calcifications, elevated levels of interferon-alpha and white blood cells in the cerebrospinal fluid.[provided by RefSeq, Aug 2009]

THSD8 (HGNC:53785): (thrombospondin type 1 domain containing 8)

HOOK2 (HGNC:19885): (hook microtubule tethering protein 2) Hook proteins are cytosolic coiled-coil proteins that contain conserved N-terminal domains, which attach to microtubules, and more divergent C-terminal domains, which mediate binding to organelles. The Drosophila Hook protein is a component of the endocytic compartment.[supplied by OMIM, Apr 2004]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain Ribonuclease H2 subunit A (size 298) in uniprot entity RNH2A_HUMAN there are 15 pathogenic changes around while only 6 benign (71%) in NM_006397.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.15410888).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RNASEH2A	NM_006397.3	c.74G>T	p.Arg25Leu	missense_variant	Exon 1 of 8	ENST00000221486.6	NP_006388.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RNASEH2A	ENST00000221486.6	c.74G>T	p.Arg25Leu	missense_variant	Exon 1 of 8	1	NM_006397.3	ENSP00000221486.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000141 AC: 2 AN: 1420070 Hom.: 0 Cov.: 31 AF XY: 0.00000142 AC XY: 1 AN XY: 702280

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000183

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Aicardi-Goutieres syndrome 4 Uncertain:1

Jun 20, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals with RNASEH2A-related disease. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The leucine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with leucine at codon 25 of the RNASEH2A protein (p.Arg25Leu). The arginine residue is weakly conserved and there is a moderate physicochemical difference between arginine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.082
BayesDel_addAF	Benign	-0.072	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	14
DANN	Benign	0.97
DEOGEN2	Uncertain	0.45	T;.
Eigen	Benign	-0.63
Eigen_PC	Benign	-0.58
FATHMM_MKL	Benign	0.26	N
LIST_S2	Benign	0.55	T;T
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.15	T;T
MetaSVM	Benign	-0.71	T
MutationAssessor	Benign	0.95	L;.
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-3.2	D;.
REVEL	Benign	0.19
Sift	Benign	0.17	T;.
Sift4G	Benign	0.23	T;.
Polyphen		0.0010	B;.
Vest4		0.19
MutPred		0.47		Gain of catalytic residue at R25 (P = 0.0028);.;
MVP		0.74
MPC		0.27
ClinPred		0.35	T
GERP RS		1.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2
Varity_R		0.28
gMVP		0.59

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.16		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs955631391; hg19: chr19-12917561;