NM_000222.3:c.1486G>A

Variant names:

• chr4-54725996-G-A
• rs143179681
• NM_000222.3:c.1486G>A

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 1P and 13B. PP2 BP4_Strong BP6 BS1 BS2

The NM_000222.3(KIT):​c.1486G>A​(p.Asp496Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000397 in 1,614,044 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). Synonymous variant affecting the same amino acid position (i.e. D496D) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00018 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000025 (0 hom.)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 1.01
• Publications: 8 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: Benign. The variant received -12 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=0.047899723).
• BP6: Variant 4-54725996-G-A is Benign according to our data. Variant chr4-54725996-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 409753.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000184 (28/152208) while in subpopulation AFR AF = 0.000555 (23/41456). AF 95% confidence interval is 0.000379. There are 0 homozygotes in GnomAd4. There are 15 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High AC in GnomAd4 at 28 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.1486G>A	p.Asp496Asn	missense	Exon 9 of 21	NP_000213.1
	KIT	NM_001385284.1		c.1489G>A	p.Asp497Asn	missense	Exon 9 of 21	NP_001372213.1
	KIT	NM_001385290.1		c.1489G>A	p.Asp497Asn	missense	Exon 9 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.1486G>A	p.Asp496Asn	missense	Exon 9 of 21	ENSP00000288135.6
	KIT	ENST00000412167.7	TSL:1	c.1489G>A	p.Asp497Asn	missense	Exon 9 of 21	ENSP00000390987.3
	KIT	ENST00000687109.1		c.1489G>A	p.Asp497Asn	missense	Exon 9 of 21	ENSP00000509371.1

Frequencies

GnomAD3 genomes AF: 0.000184 AC: 28 AN: 152208 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000555

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000597 AC: 15 AN: 251182 AF XY: 0.0000589

Gnomad AFR exome AF: 0.000308

Gnomad AMR exome AF: 0.000231

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000246 AC: 36 AN: 1461836 Hom.: 0 Cov.: 32 AF XY: 0.0000316 AC XY: 23 AN XY: 727220

African (AFR) AF: 0.000448 AC: 15 AN: 33480

American (AMR) AF: 0.000179 AC: 8 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

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

European-Non Finnish (NFE) AF: 0.00000899 AC: 10 AN: 1111976

Other (OTH) AF: 0.0000497 AC: 3 AN: 60396

GnomAD4 genome AF: 0.000184 AC: 28 AN: 152208 Hom.: 0 Cov.: 32 AF XY: 0.000202 AC XY: 15 AN XY: 74350

African (AFR) AF: 0.000555 AC: 23 AN: 41456

American (AMR) AF: 0.000196 AC: 3 AN: 15278

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.000128

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000906 AC: 11

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

KIT-related disorder Uncertain:1

Jul 13, 2023

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The KIT c.1486G>A variant is predicted to result in the amino acid substitution p.Asp496Asn. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.032% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/4-55592162-G-A). It has conflicting interpretations of likely benign and uncertain significance (https://preview.ncbi.nlm.nih.gov/clinvar/variation/409753/), At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence.

not provided Uncertain:1

Apr 27, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 25343854, 25595173, 28327988)

Gastrointestinal stromal tumor Uncertain:1

Jan 23, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with asparagine, which is neutral and polar, at codon 496 of the KIT protein (p.Asp496Asn). This variant is present in population databases (rs143179681, gnomAD 0.03%). 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: 409753). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The asparagine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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.

Hereditary cancer-predisposing syndrome Benign:1

May 25, 2023

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	0.062
BayesDel_addAF	Benign	-0.41	T
BayesDel_noAF	Benign	-0.53
CADD	Benign	17
DANN	Benign	0.93
DEOGEN2	Benign	0.20	T
Eigen	Benign	-0.60
Eigen_PC	Benign	-0.41
FATHMM_MKL	Benign	0.52	D
LIST_S2	Benign	0.69	T
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.048	T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	1.1	L
PhyloP100		1.0
PrimateAI	Benign	0.32	T
PROVEAN	Benign	0.060	N
REVEL	Benign	0.025
Sift	Benign	0.30	T
Sift4G	Benign	0.50	T
Polyphen		0.0	B
Vest4		0.12
MVP		0.63
MPC		0.43
ClinPred		0.063	T
GERP RS		3.3
Varity_R		0.21
gMVP		0.72
Mutation Taster		=92/8	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs143179681; hg19: chr4-55592162; COSMIC: COSV55395531;