chr7-129018046-G-C

Position:

• chr7-129018046-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_012470.4(TNPO3):​c.232C>G​(p.Leu78Val) 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 (★). Synonymous variant affecting the same amino acid position (i.e. L78L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNPO3 NM_012470.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.02

Genes affected

TNPO3 (HGNC:17103): (transportin 3) The protein encoded by this gene is a nuclear import receptor for serine/arginine-rich (SR) proteins such as the splicing factors SFRS1 and SFRS2. The encoded protein has also been shown to be involved in HIV-1 infection, apparently through interaction with the HIV-1 capsid protein. Several protein-coding and non-coding transcript variants have been found for this gene. [provided by RefSeq, Apr 2020]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TNPO3. . Gene score misZ 3.442 (greater than the threshold 3.09). Trascript score misZ 3.4155 (greater than threshold 3.09). GenCC has associacion of gene with autosomal dominant limb-girdle muscular dystrophy type 1F.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.768

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNPO3	NM_012470.4	c.232C>G	p.Leu78Val	missense_variant	2/23	ENST00000265388.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNPO3	ENST00000265388.10	c.232C>G	p.Leu78Val	missense_variant	2/23	1	NM_012470.4	P1

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

Autosomal dominant limb-girdle muscular dystrophy type 1F Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 11, 2019

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TNPO3-related disease. This sequence change replaces leucine with valine at codon 78 of the TNPO3 protein (p.Leu78Val). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and valine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.67
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Benign	0.29	T;T;T;.;T
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.95	D;D;D;D;.
M_CAP	Benign	0.040	D
MetaRNN	Pathogenic	0.77	D;D;D;D;D
MetaSVM	Uncertain	-0.062	T
MutationAssessor	Uncertain	2.2	M;.;.;M;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.72	T
PROVEAN	Uncertain	-2.7	D;.;D;D;D
REVEL	Uncertain	0.60
Sift	Pathogenic	0.0	D;.;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	D;D;.;.;D
Vest4		0.79
MutPred		0.66		Loss of stability (P = 0.1178);Loss of stability (P = 0.1178);.;Loss of stability (P = 0.1178);Loss of stability (P = 0.1178);
MVP		0.80
MPC		2.5
ClinPred		0.98	D
GERP RS		5.5
Varity_R		0.77
gMVP		0.69

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: rs1554441599; hg19: chr7-128658100; COSMIC: COSV99603594;