NM_000051.4:c.767A>G

Variant names:

• chr11-108244892-A-G
• rs907941927
• NM_000051.4:c.767A>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000051.4(ATM):​c.767A>G​(p.Asp256Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,554 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 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. D256V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ATM NM_000051.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 8.65
• Publications: 1 publications found

Genes affected

ATM (HGNC:795): (ATM serine/threonine kinase) The protein encoded by this gene belongs to the PI3/PI4-kinase family. This protein is an important cell cycle checkpoint kinase that phosphorylates; thus, it functions as a regulator of a wide variety of downstream proteins, including tumor suppressor proteins p53 and BRCA1, checkpoint kinase CHK2, checkpoint proteins RAD17 and RAD9, and DNA repair protein NBS1. This protein and the closely related kinase ATR are thought to be master controllers of cell cycle checkpoint signaling pathways that are required for cell response to DNA damage and for genome stability. Mutations in this gene are associated with ataxia telangiectasia, an autosomal recessive disorder. [provided by RefSeq, Aug 2010]

ATM Gene-Disease associations (from GenCC):

• hereditary breast carcinoma

  Inheritance: AD Classification: DEFINITIVE Submitted by: Ambry Genetics, ClinGen
• ataxia telangiectasia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, ClinGen, Laboratory for Molecular Medicine, Orphanet
• hereditary nonpolyposis colon cancer

  Inheritance: AD Classification: MODERATE, LIMITED Submitted by: ClinGen, Ambry Genetics
• prostate cancer

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• sarcoma

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• familial ovarian cancer

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• gastric carcinoma

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 42 uncertain in NM_000051.4
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ATM	NM_000051.4	c.767A>G	p.Asp256Gly	missense_variant	Exon 7 of 63	ENST00000675843.1	NP_000042.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ATM	ENST00000675843.1	c.767A>G	p.Asp256Gly	missense_variant	Exon 7 of 63		NM_000051.4	ENSP00000501606.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461554 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727094

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.00 AC: 0 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39636

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53378

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111842

Other (OTH) AF: 0.00 AC: 0 AN: 60378

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ataxia-telangiectasia syndrome Uncertain:1

Mar 10, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. 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: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C15"). This variant has not been reported in the literature in individuals with ATM-related conditions. ClinVar contains an entry for this variant (Variation ID: 453698). This variant is not present in population databases (ExAC no frequency). This sequence change replaces aspartic acid with glycine at codon 256 of the ATM protein (p.Asp256Gly). The aspartic acid residue is weakly conserved and there is a moderate physicochemical difference between aspartic acid and glycine.

Hereditary cancer-predisposing syndrome Uncertain:1

Jul 31, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D256G variant (also known as c.767A>G), located in coding exon 6 of the ATM gene, results from an A to G substitution at nucleotide position 767. The aspartic acid at codon 256 is replaced by glycine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Uncertain	0.061	T
BayesDel_noAF	Benign	-0.15
CADD	Uncertain	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.0	.;T;T
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.88	D;D;.
M_CAP	Uncertain	0.095	D
MetaRNN	Benign	0.42	T;T;T
MetaSVM	Benign	-0.56	T
MutationAssessor	Benign	0.0	.;L;L
PhyloP100		8.7
PrimateAI	Benign	0.38	T
PROVEAN	Uncertain	-3.7	D;D;D
REVEL	Uncertain	0.32
Sift	Uncertain	0.0060	D;D;D
Sift4G	Uncertain	0.010	D;D;D
Vest4		0.0
ClinPred		0.98	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.52
gMVP		0.46
Mutation Taster		=51/49	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.21		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs907941927; hg19: chr11-108115619;