rs121434518

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_015474.4(SAMHD1):c.445C>T(p.Gln149*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,788 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 Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Q149Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SAMHD1
NM_015474.4 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, single submitter P:2O:1

Conservation

PhyloP100: 10.0

Publications

5 publications found

Variant links:

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: Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P
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

SAMHD1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 20-36935093-G-A is Pathogenic according to our data. Variant chr20-36935093-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 4070.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SAMHD1	NM_015474.4 link	c.445C>T	p.Gln149*	stop_gained	Exon 4 of 16	ENST00000646673.2	NP_056289.2	Q9Y3Z3-1Q59H15
SAMHD1	NM_001363729.2 link	c.445C>T	p.Gln149*	stop_gained	Exon 4 of 15		NP_001350658.1
SAMHD1	NM_001363733.2 link	c.445C>T	p.Gln149*	stop_gained	Exon 4 of 16		NP_001350662.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SAMHD1	ENST00000646673.2 link	c.445C>T	p.Gln149*	stop_gained	Exon 4 of 16		NM_015474.4	ENSP00000493536.2		Q9Y3Z3-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461788

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727210

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111918

Other (OTH)

AF:

0.00

AC:

AN:

60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2Other:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Aicardi-Goutieres syndrome 5

Pathogenic:2Other:1

GeneReviews

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

- -

Jan 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this premature translational stop signal affects SAMHD1 function (PMID: 19525956, 22461318). This sequence change creates a premature translational stop signal (p.Gln149*) in the SAMHD1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SAMHD1 are known to be pathogenic (PMID: 19525956, 22461318). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with Aicardi-Goutieres syndrome (PMID: 19525956). ClinVar contains an entry for this variant (Variation ID: 4070). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. -

Jul 01, 2009

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.66

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

1.3

Eigen_PC

Pathogenic

1.2

FATHMM_MKL

Pathogenic

0.99

PhyloP100

Vest4

0.94

GERP RS

6.0

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over