rs1553881787

chr4-54658072-G-Achr4-54658072-G-Cchr4-54658072-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_000222.3(KIT):c.58G>A(p.Val20Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict 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. V20F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.488

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 Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, KIT
• BP4: Computational evidence support a benign effect (MetaRNN=0.11188707).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KIT	NM_000222.3	c.58G>A	p.Val20Ile	missense_variant	1/21	ENST00000288135.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KIT	ENST00000288135.6	c.58G>A	p.Val20Ile	missense_variant	1/21	1	NM_000222.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Gastrointestinal stromal tumor Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 13, 2020

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 (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 and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with KIT-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with isoleucine at codon 20 of the KIT protein (p.Val20Ile). The valine residue is moderately conserved and there is a small physicochemical difference between valine and isoleucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.098
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.52
Cadd	Benign	18
Dann	Benign	0.86
Eigen	Benign	-0.91
Eigen_PC	Benign	-0.85
FATHMM_MKL	Benign	0.68	D
LIST_S2	Benign	0.79	T;T
M_CAP	Benign	0.047	D
MetaRNN	Benign	0.11	T;T
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	0.0	N;N
MutationTaster	Benign	1.0	N;N
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-0.20	N;N
REVEL	Benign	0.076
Sift	Benign	0.68	T;T
Sift4G	Benign	0.48	T;T
Polyphen		0.017	B;B
Vest4		0.26
MutPred		0.29		Gain of glycosylation at S25 (P = 0.0275);Gain of glycosylation at S25 (P = 0.0275);
MVP		0.48
MPC		0.39
ClinPred		0.052	T
GERP RS		0.35
Varity_R		0.027
gMVP		0.15

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553881787; hg19: chr4-55524239; COSMIC: COSV55408868;