12-8822712-C-A

Position:

• chr12-8822712-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_144670.6(A2ML1):​c.61C>A​(p.Pro21Thr) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,782 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P21A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: A2ML1 NM_144670.6 missense, splice_region
• Scores: Splicing: ADA: 0.9690
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.87

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.30719686).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
A2ML1	NM_144670.6	c.61C>A	p.Pro21Thr	missense_variant, splice_region_variant	1/36	ENST00000299698.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
A2ML1	ENST00000299698.12	c.61C>A	p.Pro21Thr	missense_variant, splice_region_variant	1/36	1	NM_144670.6	P1
A2ML1-AS1	ENST00000537288.1	n.286+7950G>T		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461782 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727198

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 24, 2021

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with A2ML1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 21 of the A2ML1 protein (p.Pro21Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.39
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.045	T
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Benign	0.44	T
M_CAP	Benign	0.0037	T
MetaRNN	Benign	0.31	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.4	L
MutationTaster	Benign	0.96	N
PrimateAI	Benign	0.43	T
PROVEAN	Uncertain	-4.2	D
REVEL	Benign	0.17
Sift	Uncertain	0.0080	D
Sift4G	Benign	0.10	T
Polyphen		0.93	P
Vest4		0.22
MutPred		0.66		Gain of catalytic residue at P21 (P = 0.0513);
MVP		0.19
MPC		0.32
ClinPred		0.95	D
GERP RS		4.3
Varity_R		0.21
gMVP		0.68

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.97
dbscSNV1_RF	Benign	0.69
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

No publications associated with this variant yet.

Other links and lift over

hg19: chr12-8975308;