12-8822706-G-A

Variant names:

• chr12-8822706-G-A
• rs1720800547
• NM_144670.6:c.55G>A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP6

The NM_144670.6(A2ML1):​c.55G>A​(p.Glu19Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,810 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: A2ML1 NM_144670.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: -0.00200

Genes affected

A2ML1 (HGNC:23336): (alpha-2-macroglobulin like 1) This gene encodes a member of the alpha-macroglobulin superfamily. The encoded protein is thought to be an N-glycosylated monomeric protein that acts as an inhibitor of several proteases. It has been shown to form covalent interactions with proteases, and has been reported as the p170 antigen recognized by autoantibodies in the autoimmune disease paraneoplastic pemphigus (PNP; PMID:20805888). Mutations in these gene have also been associated with some cases of Noonan syndrome (NS; PMID:24939586) as well as some cases of otitis media (PMID:26121085). Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Aug 2015]

A2ML1-AS1 (HGNC:41022): (A2ML1 antisense RNA 1)

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.035844892).
• BP6: Variant 12-8822706-G-A is Benign according to our data. Variant chr12-8822706-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 2449320.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
A2ML1	NM_144670.6	c.55G>A	p.Glu19Lys	missense_variant	Exon 1 of 36	ENST00000299698.12	NP_653271.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
A2ML1	ENST00000299698.12	c.55G>A	p.Glu19Lys	missense_variant	Exon 1 of 36	1	NM_144670.6	ENSP00000299698.7
A2ML1-AS1	ENST00000537288.1	n.286+7956C>T		intron_variant	Intron 1 of 1	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461810 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727204

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Jul 01, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 19 of the A2ML1 protein (p.Glu19Lys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with A2ML1-related conditions. ClinVar contains an entry for this variant (Variation ID: 2449320). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The lysine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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 specified Benign:1

Nov 02, 2022

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.063
BayesDel_addAF	Benign	-0.36	T
BayesDel_noAF	Benign	-0.75
CADD	Benign	1.9
DANN	Uncertain	0.98
DEOGEN2	Benign	0.0027	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.0073	N
LIST_S2	Benign	0.39	T
M_CAP	Benign	0.0018	T
MetaRNN	Benign	0.036	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	-1.1	N
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-0.57	N
REVEL	Benign	0.10
Sift	Benign	0.68	T
Sift4G	Benign	1.0	T
Polyphen		0.0	B
Vest4		0.094
MutPred		0.43		Gain of ubiquitination at E19 (P = 0.0146);
MVP		0.040
MPC		0.12
ClinPred		0.14	T
GERP RS		-0.85
Varity_R		0.040
gMVP		0.53

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: rs1720800547; hg19: chr12-8975302;