rs201562272
Variant summary
Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2
The NM_144670.6(A2ML1):c.2405G>A(p.Arg802His) variant causes a missense change. The variant allele was found at a frequency of 0.000458 in 1,614,158 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R802C) has been classified as Likely benign.
Frequency
Consequence
NM_144670.6 missense
Scores
Clinical Significance
Conservation
Publications
- Noonan syndromeInheritance: AD Classification: SUPPORTIVE, LIMITED, NO_KNOWN Submitted by: Genomics England PanelApp, ClinGen, Orphanet
 
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ACMG classification
Our verdict: Benign. The variant received -9 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt | 
|---|---|---|---|---|---|---|---|---|---|---|
| A2ML1 | ENST00000299698.12  | c.2405G>A | p.Arg802His | missense_variant | Exon 19 of 36 | 1 | NM_144670.6 | ENSP00000299698.7 | ||
| A2ML1 | ENST00000541459.5  | c.1055G>A | p.Arg352His | missense_variant | Exon 8 of 25 | 2 | ENSP00000443174.1 | |||
| A2ML1 | ENST00000539547.5  | c.932G>A | p.Arg311His | missense_variant | Exon 8 of 25 | 2 | ENSP00000438292.1 | 
Frequencies
GnomAD3 genomes   AF:  0.000381  AC: 58AN: 152154Hom.:  1  Cov.: 32 show subpopulations 
GnomAD2 exomes  AF:  0.000657  AC: 164AN: 249558 AF XY:  0.000687   show subpopulations 
GnomAD4 exome  AF:  0.000467  AC: 682AN: 1461886Hom.:  4  Cov.: 37 AF XY:  0.000494  AC XY: 359AN XY: 727244 show subpopulations 
Age Distribution
GnomAD4 genome   AF:  0.000381  AC: 58AN: 152272Hom.:  1  Cov.: 32 AF XY:  0.000376  AC XY: 28AN XY: 74456 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
not provided    Uncertain:2Benign:1 
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not specified    Benign:2 
Variant summary: A2ML1 c.2405G>A (p.Arg802His) results in a non-conservative amino acid change located in the Alpha-2-macroglobulin domain (IPR001599) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00066 in 249558 control chromosomes, predominantly at a frequency of 0.0015 within the South Asian subpopulation in the gnomAD database, including 1 homozygote. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 375 fold of the estimated maximal expected allele frequency for a pathogenic variant in A2ML1 causing Noonan Syndrome phenotype (4e-06), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. c.2405G>A has been reported in the literature in individuals affected with Noonan Syndrome, including one de novo occurrence (Vissers_2015, Tidyman_2016, Brinkmann_2020). These data do not allow any conclusion about variant significance. Co-occurrences with other pathogenic variants have been reported (RAF1 c.770C>T , p.Ser257Leu; MAP2K1 c.275T>G, p.Leu92Arg) (Brinkmann_2020), providing supporting evidence for a benign role. At least one publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (Vissers_2015). Three ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=2) and likely benign (n=1). Based on the evidence outlined above, the variant was classified as likely benign. -
This variant has been previously published as a causal variant for a disorder resembling Noonan syndrome by Vissers et al (2015). The allele frequency of this variant in gnomAD is greater than expected for Noonan syndrome (5.98e-4) (BS1). In-silico prediction yields consistent gene function affecting result (PP3). The variant was once found in a patient harbouring a known causal RAF1 variant and once in a patient harbouring a known causal MAP2K1 variant, fully explaining the phenotypes in both patients (BP5). Additionally, the variant was found to be inherited by the index patient's unaffected father in one case (BS2). -
A2ML1-related disorder    Benign:1 
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Noonan syndrome    Benign:1 
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Computational scores
Source: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at