NM_000038.6:c.920A>T

Variant names:

• chr5-112815580-A-T
• rs869312787
• NM_000038.6:c.920A>T

Variant summary

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

The NM_000038.6(APC):​c.920A>T​(p.His307Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,458,656 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. H307Y) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: APC NM_000038.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 9.08
• Publications: 2 publications found

Genes affected

APC (HGNC:583): (APC regulator of WNT signaling pathway) This gene encodes a tumor suppressor protein that acts as an antagonist of the Wnt signaling pathway. It is also involved in other processes including cell migration and adhesion, transcriptional activation, and apoptosis. Defects in this gene cause familial adenomatous polyposis (FAP), an autosomal dominant pre-malignant disease that usually progresses to malignancy. Mutations in the APC gene have been found to occur in most colorectal cancers, where disease-associated mutations tend to be clustered in a small region designated the mutation cluster region (MCR) and result in a truncated protein product. [provided by RefSeq, Jun 2022]

APC Gene-Disease associations (from GenCC):

• classic or attenuated familial adenomatous polyposis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• desmoid tumor

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
• familial adenomatous polyposis 1

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
• gastric adenocarcinoma and proximal polyposis of the stomach

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
• sarcoma

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• APC-related attenuated familial adenomatous polyposis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Turcot syndrome with polyposis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Cenani-Lenz syndactyly syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

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 0 benign, 40 uncertain in NM_000038.6
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APC	NM_000038.6	c.920A>T	p.His307Leu	missense_variant	Exon 9 of 16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.920A>T	p.His307Leu	missense_variant	Exon 9 of 16	5	NM_000038.6	ENSP00000257430.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1458656 Hom.: 0 Cov.: 30 AF XY: 0.00000276 AC XY: 2 AN XY: 725796

African (AFR) AF: 0.00 AC: 0 AN: 33362

American (AMR) AF: 0.00 AC: 0 AN: 44622

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26048

East Asian (EAS) AF: 0.00 AC: 0 AN: 39540

South Asian (SAS) AF: 0.00 AC: 0 AN: 86210

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53138

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5736

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1109860

Other (OTH) AF: 0.00 AC: 0 AN: 60140

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Uncertain:1

Oct 22, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, this variant is a rare missense change that is not predicted to affect protein function. While it is absent from the population and reported in an affected individual, the available evidence is currently insufficient to determine its role 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies. This variant has been reported in an individual affected with endometrial cancer (PMID: 26845104). ClinVar contains an entry for this variant (Variation ID: 224556). This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with leucine at codon 307 of the APC protein (p.His307Leu). The histidine residue is highly conserved and there is a moderate physicochemical difference between histidine and leucine. -

Colorectal cancer, susceptibility to Uncertain:1

Nov 20, 2015

University of Washington Department of Laboratory Medicine, University of Washington

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Nov 18, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.H307L variant (also known as c.920A>T), located in coding exon 8 of the APC gene, results from an A to T substitution at nucleotide position 920. The histidine at codon 307 is replaced by leucine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. 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	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	26
DANN	Benign	0.97
DEOGEN2	Uncertain	0.66	.;D;D;T
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;.;D;D
M_CAP	Uncertain	0.21	D
MetaRNN	Uncertain	0.70	D;D;D;D
MetaSVM	Uncertain	0.71	D
MutationAssessor	Uncertain	2.1	.;M;M;.
PhyloP100		9.1
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-3.4	D;D;D;D
REVEL	Pathogenic	0.73
Sift	Uncertain	0.0040	D;D;D;D
Sift4G	Uncertain	0.021	D;D;D;D
Polyphen		0.98	.;D;D;.
Vest4		0.73, 0.76
MutPred		0.26		.;Loss of loop (P = 0.0374);Loss of loop (P = 0.0374);Loss of loop (P = 0.0374);
MVP		0.97
ClinPred		0.97	D
GERP RS		5.1
Varity_R		0.47
gMVP		0.64
Mutation Taster		=34/66	disease causing

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

Other links and lift over

dbSNP: rs869312787; hg19: chr5-112151277;