chr12-8822695-C-A

Position:

• chr12-8822695-C-A

Variant summary

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

The NM_144670.6(A2ML1):​c.44C>A​(p.Ala15Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: A2ML1 NM_144670.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -0.0100

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
A2ML1	NM_144670.6	c.44C>A	p.Ala15Asp	missense_variant	1/36	ENST00000299698.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
A2ML1	ENST00000299698.12	c.44C>A	p.Ala15Asp	missense_variant	1/36	1	NM_144670.6	P1
A2ML1-AS1	ENST00000537288.1	n.286+7967G>T		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 24, 2024	The p.A15D variant (also known as c.44C>A), located in coding exon 1 of the A2ML1 gene, results from a C to A substitution at nucleotide position 44. The alanine at codon 15 is replaced by aspartic acid, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 23, 2020	Variant summary: A2ML1 c.44C>A (p.Ala15Asp) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 249556 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.44C>A in individuals affected with Noonan Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Benign	-0.089	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Benign	0.0065	T
Eigen	Benign	-0.51
Eigen_PC	Benign	-0.64
FATHMM_MKL	Benign	0.030	N
LIST_S2	Benign	0.48	T
M_CAP	Benign	0.0061	T
MetaRNN	Uncertain	0.60	D
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.7	L
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-1.6	N
REVEL	Benign	0.20
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.028	D
Polyphen		0.94	P
Vest4		0.66
MutPred		0.55		Gain of relative solvent accessibility (P = 0.0215);
MVP		0.11
MPC		0.34
ClinPred		0.60	D
GERP RS		1.1
Varity_R		0.17
gMVP		0.70

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: rs1942780601; hg19: chr12-8975291;