chr16-1222002-C-T

Position:

• chr16-1222002-C-T

Variant summary

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

The NM_012467.4(TPSG1):​c.752G>A​(p.Arg251Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,460,384 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: TPSG1 NM_012467.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -2.30

Genes affected

TPSG1 (HGNC:14134): (tryptase gamma 1) Tryptases comprise a family of trypsin-like serine proteases, the peptidase family S1. Tryptases are enzymatically active only as heparin-stabilized tetramers, and they are resistant to all known endogenous proteinase inhibitors. Several tryptase genes are clustered on chromosome 16p13.3. There is uncertainty regarding the number of genes in this cluster. Currently four functional genes - alpha I, beta I, beta II and gamma I - have been identified. And beta I has an allelic variant named alpha II, beta II has an allelic variant beta III, also gamma I has an allelic variant gamma II. Beta tryptases appear to be the main isoenzymes expressed in mast cells; whereas in basophils, alpha-tryptases predominant. This gene differs from other members of the tryptase gene family in that it has C-terminal hydrophobic domain, which may serve as a membrane anchor. Tryptases have been implicated as mediators in the pathogenesis of asthma and other allergic and inflammatory disorders. [provided by RefSeq, Jul 2008]

CACNA1H (HGNC:1395): (calcium voltage-gated channel subunit alpha1 H) This gene encodes a T-type member of the alpha-1 subunit family, a protein in the voltage-dependent calcium channel complex. Calcium channels mediate the influx of calcium ions into the cell upon membrane polarization and consist of a complex of alpha-1, alpha-2/delta, beta, and gamma subunits in a 1:1:1:1 ratio. The alpha-1 subunit has 24 transmembrane segments and forms the pore through which ions pass into the cell. There are multiple isoforms of each of the proteins in the complex, either encoded by different genes or the result of alternative splicing of transcripts. Alternate transcriptional splice variants, encoding different isoforms, have been characterized for the gene described here. Studies suggest certain mutations in this gene lead to childhood absence epilepsy (CAE). [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=0.26071602).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TPSG1	NM_012467.4	c.752G>A	p.Arg251Lys	missense_variant	6/6	ENST00000234798.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TPSG1	ENST00000234798.5	c.752G>A	p.Arg251Lys	missense_variant	6/6	1	NM_012467.4	P1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460384 Hom.: 0 Cov.: 77 AF XY: 0.00000551 AC XY: 4 AN XY: 726476

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Bravo AF: 0.00000378

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

Oct 05, 2023

The c.752G>A (p.R251K) alteration is located in exon 6 (coding exon 6) of the TPSG1 gene. This alteration results from a G to A substitution at nucleotide position 752, causing the arginine (R) at amino acid position 251 to be replaced by a lysine (K). 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	0.13
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.40
CADD	Benign	8.9
DANN	Benign	0.90
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.018	N
M_CAP	Uncertain	0.12	D
MetaRNN	Benign	0.26	T
MetaSVM	Benign	-0.50	T
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-1.9	N
REVEL	Uncertain	0.33
Sift	Benign	0.13	T
Sift4G	Benign	0.17	T
Vest4		0.11
MutPred		0.49		Gain of methylation at R251 (P = 0.0184);
MVP		0.41
MPC		0.0036
ClinPred		0.18	T
GERP RS		-0.22
gMVP		0.55

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: rs762075870; hg19: chr16-1272002;