chr4-54728055-A-C

Variant names:

• chr4-54728055-A-C
• rs121913512
• NM_000222.3:c.1924A>C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 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 (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KIT NM_000222.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• 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 Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.897

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KIT	NM_000222.3	c.1924A>C	p.Lys642Gln	missense_variant	Exon 13 of 21	ENST00000288135.6	NP_000213.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KIT	ENST00000288135.6	c.1924A>C	p.Lys642Gln	missense_variant	Exon 13 of 21	1	NM_000222.3	ENSP00000288135.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gastrointestinal stromal tumor Uncertain:1

Dec 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of gastrointestinal stromal tumor syndrome (PMID: 27263309). ClinVar contains an entry for this variant (Variation ID: 2568309). 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. 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. 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 Uncertain:1

May 17, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Acute myeloid leukemia;C0080024:Piebaldism;C0238198:Gastrointestinal stromal tumor;C1136033:Cutaneous mastocytosis;C1336708:Germ cell tumor of testis Uncertain:1

Apr 09, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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
DEOGEN2	Uncertain	0.79	.;D
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
MutationAssessor	Benign	0.71	.;N
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;