chr4-54727295-G-C

Variant names:

• chr4-54727295-G-C
• rs756179543
• NM_000222.3:c.1618G>C

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 1P and 7B. PP2 BP4_Moderate BS1_Supporting BS2

The NM_000222.3(KIT):​c.1618G>C​(p.Val540Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000062 in 1,614,168 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V540A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000066 (0 hom.)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6 B:1
• Conservation: PhyloP100: 3.29
• Publications: 5 publications found

Genes affected

KIT (HGNC:6342): (KIT proto-oncogene, receptor tyrosine kinase) This gene encodes a receptor tyrosine kinase. This gene was initially identified as a homolog of the feline sarcoma viral oncogene v-kit and is often referred to as proto-oncogene c-Kit. The canonical form of this glycosylated transmembrane protein has an N-terminal extracellular region with five immunoglobulin-like domains, a transmembrane region, and an intracellular tyrosine kinase domain at the C-terminus. Upon activation by its cytokine ligand, stem cell factor (SCF), this protein phosphorylates multiple intracellular proteins that play a role in in the proliferation, differentiation, migration and apoptosis of many cell types and thereby plays an important role in hematopoiesis, stem cell maintenance, gametogenesis, melanogenesis, and in mast cell development, migration and function. This protein can be a membrane-bound or soluble protein. Mutations in this gene are associated with gastrointestinal stromal tumors, mast cell disease, acute myelogenous leukemia, and piebaldism. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2020]

KIT Gene-Disease associations (from GenCC):

• gastrointestinal stromal tumor

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

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp
• cutaneous mastocytosis

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• mastocytosis

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics

ACMG classification

Our verdict: Likely_benign. The variant received -6 ACMG points.

• PP2: Missense variant in the KIT gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 54 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: 2.5806 (below the threshold of 3.09). Trascript score misZ: 4.1549 (above the threshold of 3.09). GenCC associations: The gene is linked to cutaneous mastocytosis, gastrointestinal stromal tumor, mastocytosis, piebaldism.
• BP4: Computational evidence support a benign effect (MetaRNN=0.07583824).
• BS1: Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.0000197 (3/152338) while in subpopulation EAS AF = 0.000578 (3/5188). AF 95% confidence interval is 0.000157. There are 0 homozygotes in GnomAd4. There are 1 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 97 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000222.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KIT	NM_000222.3	MANE Select	c.1618G>C	p.Val540Leu	missense	Exon 10 of 21	NP_000213.1
	KIT	NM_001385284.1		c.1621G>C	p.Val541Leu	missense	Exon 10 of 21	NP_001372213.1
	KIT	NM_001385290.1		c.1621G>C	p.Val541Leu	missense	Exon 10 of 21	NP_001372219.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KIT	ENST00000288135.6	TSL:1 MANE Select	c.1618G>C	p.Val540Leu	missense	Exon 10 of 21	ENSP00000288135.6
	KIT	ENST00000412167.7	TSL:1	c.1609G>C	p.Val537Leu	missense	Exon 10 of 21	ENSP00000390987.3
	KIT	ENST00000687109.1		c.1621G>C	p.Val541Leu	missense	Exon 10 of 21	ENSP00000509371.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152220 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000577

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000796 AC: 2 AN: 251250 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000664 AC: 97 AN: 1461830 Hom.: 0 Cov.: 32 AF XY: 0.0000688 AC XY: 50 AN XY: 727232

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00239 AC: 95 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111958

Other (OTH) AF: 0.0000331 AC: 2 AN: 60396

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152338 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74494

African (AFR) AF: 0.00 AC: 0 AN: 41582

American (AMR) AF: 0.00 AC: 0 AN: 15306

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.000578 AC: 3 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000165 AC: 2

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Gastrointestinal stromal tumor Uncertain:3

Aug 23, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 540 of the KIT protein (p.Val540Leu). This variant is present in population databases (rs756179543, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with KIT-related conditions. ClinVar contains an entry for this variant (Variation ID: 409741). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The leucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Experimental studies have shown that this missense change affects KIT function (PMID: 20890793). 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.

Feb 16, 2024

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Mastocytosis Uncertain:1

Aug 23, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

Piebaldism Uncertain:1

Aug 23, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

not provided Uncertain:1

Oct 18, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in pediatric patients with acute myeloid leukemia or cutaneous mastocytosis (Tokumasu et al., 2015; Arase et al., 2020); Published functional studies demonstrate that p.(V540L) has transforming activity (Tsujimura et al., 2010); This variant is associated with the following publications: (PMID: 25975190, 32077120, 20890793, 17525721)

Hereditary cancer-predisposing syndrome Benign:1

Jan 21, 2025

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.30	T
BayesDel_noAF	Benign	-0.44
CADD	Benign	16
DANN	Benign	0.11
DEOGEN2	Benign	0.21	T
Eigen	Benign	-0.55
Eigen_PC	Benign	-0.37
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.022	T
MetaRNN	Benign	0.076	T
MetaSVM	Benign	-0.90	T
MutationAssessor	Benign	0.47	N
PhyloP100		3.3
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	1.2	N
REVEL	Benign	0.21
Sift	Benign	1.0	T
Sift4G	Benign	1.0	T
Polyphen		0.0050	B
Vest4		0.097
MutPred		0.40		Gain of sheet (P = 0.1208)
MVP		0.57
MPC		0.44
ClinPred		0.073	T
GERP RS		4.2
Varity_R		0.028
gMVP		0.77
Mutation Taster		=83/17	polymorphism

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: rs756179543; hg19: chr4-55593461; COSMIC: COSV55421540;