chr20-36912462-T-C

Position:

• chr20-36912462-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_015474.4(SAMHD1):​c.1153A>G​(p.Met385Val) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000138 in 1,446,168 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SAMHD1 NM_015474.4 missense, splice_region
• Scores: Splicing: ADA: 0.9996
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 7.80

Genes affected

SAMHD1 (HGNC:15925): (SAM and HD domain containing deoxynucleoside triphosphate triphosphohydrolase 1) This gene may play a role in regulation of the innate immune response. The encoded protein is upregulated in response to viral infection and may be involved in mediation of tumor necrosis factor-alpha proinflammatory responses. Mutations in this gene have been associated with Aicardi-Goutieres syndrome. [provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SAMHD1	NM_015474.4	c.1153A>G	p.Met385Val	missense_variant, splice_region_variant	10/16	ENST00000646673.2	NP_056289.2
SAMHD1	NM_001363729.2	c.1153A>G	p.Met385Val	missense_variant, splice_region_variant	10/15		NP_001350658.1
SAMHD1	NM_001363733.2	c.1153A>G	p.Met385Val	missense_variant, splice_region_variant	10/16		NP_001350662.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SAMHD1	ENST00000646673.2	c.1153A>G	p.Met385Val	missense_variant, splice_region_variant	10/16		NM_015474.4	ENSP00000493536	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1446168 Hom.: 0 Cov.: 28 AF XY: 0.00 AC XY: 0 AN XY: 720584

Gnomad4 AFR exome AF: 0.0000302

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: 0.0000187

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Aicardi-Goutieres syndrome 5 Uncertain:1 Other:1

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 22, 2022	This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 385 of the SAMHD1 protein (p.Met385Val). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Aicardi-Goutieres syndrome (PMID: 19525956). ClinVar contains an entry for this variant (Variation ID: 126405). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). Experimental studies have shown that this missense change affects SAMHD1 function (PMID: 28229507). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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. -
not provided, no classification provided	literature only	GeneReviews	-	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.43
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.48	T;.;.;.
Eigen	Pathogenic	0.76
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.97	.;D;D;D
M_CAP	Pathogenic	0.72	D
MetaRNN	Pathogenic	0.98	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.0	H;H;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.58	T
PROVEAN	Uncertain	-3.4	.;D;.;.
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0030	.;D;.;.
Sift4G	Uncertain	0.0060	.;D;.;.
Polyphen		0.94	P;.;.;.
Vest4		0.98
MutPred		0.88		Loss of stability (P = 0.1774);Loss of stability (P = 0.1774);Loss of stability (P = 0.1774);.;
MVP		0.96
MPC		0.93
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.84
gMVP		0.94

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.22		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.22		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs515726140; hg19: chr20-35540865;