12-10996980-C-A

Position:

• chr12-10996980-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_176889.4(TAS2R20):​c.896G>T​(p.Cys299Phe) 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. 14/21 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TAS2R20 NM_176889.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.08

Genes affected

TAS2R20 (HGNC:19109): (taste 2 receptor member 20) This gene encodes a member of the taste receptor two family of class C G-protein coupled receptors. Receptors of this family have a short extracellular N-terminus, seven transmembrane helices, three extracellular loops and three intracellular loops, and an intracellular C-terminus. Members of this family are expressed in a subset of taste receptor cells, where they function in bitter taste reception, as well as in non-gustatory cells including those of the brain, reproductive organs, respiratory system, and gastrointestinal system. This gene maps to the taste receptor gene cluster on chromosome 12p13. [provided by RefSeq, Jul 2016]

ENSG00000275778 (HGNC:):

PRH1 (HGNC:9366): (proline rich protein HaeIII subfamily 1) This gene encodes a member of the heterogeneous family of proline-rich salivary glycoproteins. The encoded preproprotein undergoes proteolytic processing to generate one or more mature isoforms before secretion from the parotid and submandibular/sublingual glands. Multiple distinct alleles of this locus including the parotid isoelectric-focusing variant slow (PIF-s), the parotid acidic protein (Pa), and the double band slow (Db-s) isoforms have been characterized. The reference genome encodes the Db-s allele. Certain alleles of this gene are associated with susceptibility to dental caries. This gene is located in a cluster of closely related salivary proline-rich proteins on chromosome 12. Co-transcription of this gene with adjacent genes has been observed. Alternate splicing of this gene results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Oct 2015]

TAS2R14 (HGNC:14920): (taste 2 receptor member 14) This gene product belongs to the family of candidate taste receptors that are members of the G-protein-coupled receptor superfamily. These proteins are specifically expressed in the taste receptor cells of the tongue and palate epithelia. They are organized in the genome in clusters and are genetically linked to loci that influence bitter perception in mice and humans. In functional expression studies, they respond to bitter tastants. This gene maps to the taste receptor gene cluster on chromosome 12p13. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.120381206).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TAS2R20	NM_176889.4	c.896G>T	p.Cys299Phe	missense_variant	1/1	ENST00000538986.2	NP_795370.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TAS2R20	ENST00000538986.2	c.896G>T	p.Cys299Phe	missense_variant	1/1	6	NM_176889.4	ENSP00000441624.1
ENSG00000275778	ENST00000703543.1	c.-125-23259G>T		intron_variant				ENSP00000515364.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 15, 2024

The c.896G>T (p.C299F) alteration is located in exon 1 (coding exon 1) of the TAS2R20 gene. This alteration results from a G to T substitution at nucleotide position 896, causing the cysteine (C) at amino acid position 299 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.086
BayesDel_addAF	Benign	-0.26	T
BayesDel_noAF	Benign	-0.62
CADD	Benign	1.1
DANN	Benign	0.91
DEOGEN2	Benign	0.021	T
Eigen	Benign	-1.0
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.012	N
M_CAP	Benign	0.0025	T
MetaRNN	Benign	0.12	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.6	L
PrimateAI	Benign	0.27	T
PROVEAN	Uncertain	-3.4	D
REVEL	Benign	0.021
Sift	Benign	0.17	T
Sift4G	Uncertain	0.036	D
Polyphen		0.011	B
Vest4		0.15
MutPred		0.63		Gain of catalytic residue at W295 (P = 6e-04);
MVP		0.23
MPC		0.074
ClinPred		0.056	T
GERP RS		-0.90
Varity_R		0.067
gMVP		0.066

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: rs779156088; hg19: chr12-11149579;