rs121913512

chr4-54728055-A-Cchr4-54728055-A-Gchr4-54728055-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PM5 PP2 PP3_Moderate

The NM_000222.3(KIT):c.1924A>C(p.Lys642Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. K642N) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.23

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_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr4-54728055-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 13866.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant where missense usually causes diseases, KIT
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.897

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KIT	NM_000222.3	c.1924A>C	p.Lys642Gln	missense_variant	13/21	ENST00000288135.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KIT	ENST00000288135.6	c.1924A>C	p.Lys642Gln	missense_variant	13/21	1	NM_000222.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gastrointestinal stromal tumor Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 23, 2023

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. This variant disrupts the p.Lys642 amino acid residue in KIT. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11073817, 17824795, 22626674, 23648119, 29098070). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 2568309). This missense change has been observed in individual(s) with clinical features of gastrointestinal stromal tumor syndrome (PMID: 27263309). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with glutamine, which is neutral and polar, at codon 642 of the KIT protein (p.Lys642Gln). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 17, 2023

The p.K642Q variant (also known as c.1924A>C), located in coding exon 13 of the KIT gene, results from an A to C substitution at nucleotide position 1924. The lysine at codon 642 is replaced by glutamine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious 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	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.16
Cadd	Pathogenic	30
Dann	Uncertain	1.0
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.90	D;D
MetaSVM	Uncertain	0.32	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Uncertain	-3.6	D;D
REVEL	Pathogenic	0.79
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.87
MutPred		0.70		.;Loss of ubiquitination at K642 (P = 0.0167);
MVP		0.96
MPC		1.4
ClinPred		0.98	D
GERP RS		6.1
Varity_R		0.97
gMVP		0.85

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: rs121913512; hg19: chr4-55594221; COSMIC: COSV55411978; COSMIC: COSV55411978;