20-36905448-T-A

Variant names:

• chr20-36905448-T-A
• NM_015474.4:c.1326A>T
• SAMHD1 p.Arg442Arg

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_015474.4(SAMHD1):​c.1326A>T​(p.Arg442Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,454 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R442R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SAMHD1 NM_015474.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.572
• Publications: 0 publications found

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]

SAMHD1 Gene-Disease associations (from GenCC):

• Aicardi-Goutieres syndrome 5

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P, PanelApp Australia, Ambry Genetics
• SAMHD1-related type 1 interferonopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Moyamoya disease

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
• Aicardi-Goutieres syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial chilblain lupus

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• chilblain lupus 2

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• chilblain lupus

  Inheritance: AD Classification: NO_KNOWN Submitted by: Illumina

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.81).
• BP7: Synonymous conserved (PhyloP=0.572 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015474.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SAMHD1	NM_015474.4	MANE Select	c.1326A>T	p.Arg442Arg	synonymous	Exon 12 of 16	NP_056289.2
	SAMHD1	NM_001363729.2		c.1326A>T	p.Arg442Arg	synonymous	Exon 12 of 15	NP_001350658.1	Q9Y3Z3-4
	SAMHD1	NM_001363733.2		c.1326A>T	p.Arg442Arg	synonymous	Exon 12 of 16	NP_001350662.1	A0A2R8YCS7

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SAMHD1	ENST00000646673.2	MANE Select	c.1326A>T	p.Arg442Arg	synonymous	Exon 12 of 16	ENSP00000493536.2	Q9Y3Z3-1
	SAMHD1	ENST00000262878.5	TSL:1	c.1326A>T	p.Arg442Arg	synonymous	Exon 12 of 15	ENSP00000262878.5	Q9Y3Z3-4
	SAMHD1	ENST00000866371.1		c.1464A>T	p.Arg488Arg	synonymous	Exon 13 of 17	ENSP00000536430.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461454 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727074

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

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39678

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111638

Other (OTH) AF: 0.00 AC: 0 AN: 60384

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.81
CADD	Benign	4.8
DANN	Benign	0.60
PhyloP100		0.57
PromoterAI		-0.079	Neutral

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr20-35533851;