chr4-54699734-G-A

Variant names:

• chr4-54699734-G-A
• rs1553887944
• NM_000222.3:c.724G>A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2 BS2

The NM_000222.3(KIT):​c.724G>A​(p.Val242Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000041 in 1,461,712 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.29

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]

ACMG classification

Verdict is Likely_benign. Variant got -3 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 piebaldism, gastrointestinal stromal tumor, mastocytosis, cutaneous mastocytosis.
• BS2: High AC in GnomAdExome4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KIT	NM_000222.3	c.724G>A	p.Val242Met	missense_variant	Exon 4 of 21	ENST00000288135.6	NP_000213.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KIT	ENST00000288135.6	c.724G>A	p.Val242Met	missense_variant	Exon 4 of 21	1	NM_000222.3	ENSP00000288135.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461712 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727152

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gastrointestinal stromal tumor Uncertain:1

Jun 17, 2021

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 missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with KIT-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with methionine at codon 242 of the KIT protein (p.Val242Met). The valine residue is highly conserved and there is a small physicochemical difference between valine and methionine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Nov 08, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.V242M variant (also known as c.724G>A), located in coding exon 4 of the KIT gene, results from a G to A substitution at nucleotide position 724. The valine at codon 242 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. 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	0.47
BayesDel_addAF	Benign	-0.063	T
BayesDel_noAF	Benign	-0.33
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.41	.;T
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Benign	0.022	T
MetaRNN	Uncertain	0.60	D;D
MetaSVM	Benign	-0.93	T
MutationAssessor	Uncertain	2.5	M;M
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-1.0	N;N
REVEL	Benign	0.23
Sift	Uncertain	0.014	D;D
Sift4G	Benign	0.081	T;T
Polyphen		1.0	D;D
Vest4		0.41
MutPred		0.67		Gain of glycosylation at Y243 (P = 0.0469);Gain of glycosylation at Y243 (P = 0.0469);
MVP		0.45
MPC		1.3
ClinPred		0.90	D
GERP RS		5.9
Varity_R		0.18
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553887944; hg19: chr4-55565900; COSMIC: COSV105160701; COSMIC: COSV105160701;