chr11-18269782-C-G

Position:

• chr11-18269782-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_199161.5(SAA1):​c.296C>G​(p.Ala99Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,796 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: SAA1 NM_199161.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.66

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.20795277).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SAA1	NM_199161.5	c.296C>G	p.Ala99Gly	missense_variant	4/4	ENST00000356524.9
SAA1	NM_000331.6	c.296C>G	p.Ala99Gly	missense_variant	4/4
SAA1	NM_001178006.3	c.296C>G	p.Ala99Gly	missense_variant	5/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SAA1	ENST00000356524.9	c.296C>G	p.Ala99Gly	missense_variant	4/4	1	NM_199161.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461796 Hom.: 0 Cov.: 35 AF XY: 0.00000275 AC XY: 2 AN XY: 727204

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: 0.00

Gnomad4 OTH exome AF: 0.0000828

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 02, 2023

The c.296C>G (p.A99G) alteration is located in exon 4 (coding exon 3) of the SAA1 gene. This alteration results from a C to G substitution at nucleotide position 296, causing the alanine (A) at amino acid position 99 to be replaced by a glycine (G). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.25	T
BayesDel_noAF	Benign	-0.60
CADD	Benign	0.031
DANN	Benign	0.94
DEOGEN2	Benign	0.022	T;T;T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.043	N
LIST_S2	Uncertain	0.92	.;.;D
M_CAP	Benign	0.0033	T
MetaRNN	Benign	0.21	T;T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-1.7	N;N;N
REVEL	Benign	0.095
Sift	Benign	0.35	T;T;T
Sift4G	Benign	0.22	T;T;T
Vest4		0.13
MutPred		0.42		Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);
MVP		0.030
MPC		0.021
ClinPred		0.59	D
GERP RS		-6.7
gMVP		0.23

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

LitVar

Other links and lift over

dbSNP: rs1858167355; hg19: chr11-18291329;