6-32041401-G-A

Position:

• chr6-32041401-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP3

The NM_001365276.2(TNXB):​c.12683C>T​(p.Thr4228Met) variant causes a missense change. The variant allele was found at a frequency of 0.0000478 in 146,546 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000048 (0 hom., cov: 23)
  • Exomes 𝑓: 0.0000092 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TNXB NM_001365276.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.34

Genes affected

TNXB (HGNC:11976): (tenascin XB) This gene encodes a member of the tenascin family of extracellular matrix glycoproteins. The tenascins have anti-adhesive effects, as opposed to fibronectin which is adhesive. This protein is thought to function in matrix maturation during wound healing, and its deficiency has been associated with the connective tissue disorder Ehlers-Danlos syndrome. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. It is one of four genes in this cluster which have been duplicated. The duplicated copy of this gene is incomplete and is a pseudogene which is transcribed but does not encode a protein. The structure of this gene is unusual in that it overlaps the CREBL1 and CYP21A2 genes at its 5' and 3' ends, respectively. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

CYP21A2 (HGNC:2600): (cytochrome P450 family 21 subfamily A member 2) This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and hydroxylates steroids at the 21 position. Its activity is required for the synthesis of steroid hormones including cortisol and aldosterone. Mutations in this gene cause congenital adrenal hyperplasia. A related pseudogene is located near this gene; gene conversion events involving the functional gene and the pseudogene are thought to account for many cases of steroid 21-hydroxylase deficiency. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.783

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNXB	NM_001365276.2	c.12683C>T	p.Thr4228Met	missense_variant	44/44	ENST00000644971.2	NP_001352205.1
CYP21A2	NM_000500.9	c.*267G>A		3_prime_UTR_variant	10/10	ENST00000644719.2	NP_000491.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNXB	ENST00000644971.2	c.12683C>T	p.Thr4228Met	missense_variant	44/44		NM_001365276.2	ENSP00000496448.1
CYP21A2	ENST00000644719.2	c.*267G>A		3_prime_UTR_variant	10/10		NM_000500.9	ENSP00000496625.1

Frequencies

GnomAD3 genomes AF: 0.0000478 AC: 7 AN: 146546 Hom.: 0 Cov.: 23

Gnomad AFR AF: 0.000179

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000922 AC: 9 AN: 975666 Hom.: 0 Cov.: 14 AF XY: 0.0000161 AC XY: 8 AN XY: 497554

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: 0.0000101

Gnomad4 OTH exome AF: 0.0000455

GnomAD4 genome AF: 0.0000478 AC: 7 AN: 146546 Hom.: 0 Cov.: 23 AF XY: 0.0000421 AC XY: 3 AN XY: 71278

Gnomad4 AFR AF: 0.000179

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ExAC AF: 0.0000160 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Vesicoureteral reflux 8 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Pittsburgh Clinical Genomics Laboratory, University of Pittsburgh Medical Center

Aug 23, 2022

This sequence variant is a single nucleotide substitution (C>T) at coding nucleotide 12677 of the TNXB gene which results in a threonine to methionine amino acid change at residue 4226 in the TNXB-encoded Tescin-X protein. This variant has not been reported in clinical genetics databases or observed in the medical literature in individuals with TNXB-related disease, to our knowledge. This variant is present in 3/177804 alleles (0.002%) in the gnomAD control population dataset, though population counts in this region may be iccurate due to pseudogene homology. The variant alters an amino acid in the tescin-X fibrinogen C-termil domain (Uniprot). Multiple bioinformatic tools predict that this variant is likely to be damaging, and threonine is highly conserved at this protein position in vertebrates. Functiol studies testing the effects of this variant have not been performed, to our knowledge. At this time, there is insufficient evidence to determine if this variant is pathogenic or benign. Therefore, we consider it to be a variant of uncertain significance. ACMG Criteria: PM2, PP3 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.51
BayesDel_addAF	Uncertain	0.053	T
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Benign	0.085	.;.;.;.;T
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	.;D;D;D;D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.78	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
PrimateAI	Uncertain	0.71	T
PROVEAN	Uncertain	-3.8	.;.;D;D;.
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0030	.;.;D;D;.
Sift4G	Pathogenic	0.0	.;.;D;D;D
Vest4		0.49, 0.48
MVP		0.68
MPC		3.0
ClinPred		0.79	D
GERP RS		5.4
Varity_R		0.32
gMVP		0.64

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: rs780322872; hg19: chr6-32009178;