dbSNP rs2229338: SAA1:p.His89Arg (chr11-18269752-A-G) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_199161.5(SAA1):c.266A>G(p.His89Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,708 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SAA1
NM_199161.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.43

Publications

0 publications found

Variant links:

Genes affected

SAA1 (HGNC:10513): (serum amyloid A1) This gene encodes a member of the serum amyloid A family of apolipoproteins. The encoded preproprotein is proteolytically processed to generate the mature protein. This protein is a major acute phase protein that is highly expressed in response to inflammation and tissue injury. This protein also plays an important role in HDL metabolism and cholesterol homeostasis. High levels of this protein are associated with chronic inflammatory diseases including atherosclerosis, rheumatoid arthritis, Alzheimer's disease and Crohn's disease. This protein may also be a potential biomarker for certain tumors. Finally, antimicrobial activity against S. aureus and E. coli resides in the N-terminal portion of the mature protein. Alternate splicing results in multiple transcript variants that encode the same protein. A pseudogene of this gene is found on chromosome 11. [provided by RefSeq, Jul 2020]

SAA1 links:

ENSG00000303304 (HGNC:):

ENSG00000303304 links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM1

In a mutagenesis_site Reduces affinity for heparin and nearly abolishes association with HDL; when associated with A-18 and A-80. (size 0) in uniprot entity SAA1_HUMAN

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.07681623).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SAA1	NM_199161.5 link	c.266A>G	p.His89Arg	missense_variant	Exon 4 of 4	ENST00000356524.9	NP_954630.2	P0DJI8
SAA1	NM_000331.6 link	c.266A>G	p.His89Arg	missense_variant	Exon 4 of 4		NP_000322.3	P0DJI8
SAA1	NM_001178006.3 link	c.266A>G	p.His89Arg	missense_variant	Exon 5 of 5		NP_001171477.2	P0DJI8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SAA1	ENST00000356524.9 link	c.266A>G	p.His89Arg	missense_variant	Exon 4 of 4	1	NM_199161.5	ENSP00000348918.4		P0DJI8

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461708

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727166

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:

33472

American (AMR)

AF:

0.00

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111878

Other (OTH)

AF:

0.00

AC:

AN:

60380

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

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.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.076

BayesDel_addAF

Benign

-0.26

BayesDel_noAF

Benign

-0.62

CADD

Benign

0.13

(source)

DANN

Benign

0.41

DEOGEN2

Benign

0.0053

T;T;T

Eigen

Benign

-1.7

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.080

LIST_S2

Benign

0.47

.;.;T

M_CAP

Benign

0.0020

MetaRNN

Benign

0.077

T;T;T

MetaSVM

Benign

-0.95

PhyloP100

1.4

PrimateAI

Benign

0.27

PROVEAN

Benign

-0.60

N;N;N

REVEL

Benign

0.030

Sift

Benign

1.0

T;T;T

Sift4G

Benign

1.0

T;T;T

Vest4

0.035

MutPred

0.41

Gain of MoRF binding (P = 0.0384);Gain of MoRF binding (P = 0.0384);Gain of MoRF binding (P = 0.0384);

MVP

0.014

MPC

0.0077

ClinPred

0.029

GERP RS

-3.0

gMVP

0.16

Mutation Taster

=99/1

polymorphism

(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

Computational scores

Splicing

Publications

Other links and lift over