rs367543077

Variant names:

• chr1-235450286-G-A
• rs367543077
• NM_152490.5:c.1423C>T

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PVS1_Moderate PM2 PP5

The NM_152490.5(B3GALNT2):​c.1423C>T​(p.Gln475*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,576 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. Q475Q) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: B3GALNT2 NM_152490.5 stop_gained
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1 O:1
• Conservation: PhyloP100: 9.17
• Publications: 6 publications found

Genes affected

B3GALNT2 (HGNC:28596): (beta-1,3-N-acetylgalactosaminyltransferase 2) This gene encodes a member of the glycosyltransferase 31 family. The encoded protein synthesizes GalNAc:beta-1,3GlcNAc, a novel carbohydrate structure, on N- and O-glycans. Alternatively spliced transcript variants that encode different isoforms have been described. [provided by RefSeq, Mar 2013]

TBCE (HGNC:11582): (tubulin folding cofactor E) Cofactor E is one of four proteins (cofactors A, D, E, and C) involved in the pathway leading to correctly folded beta-tubulin from folding intermediates. Cofactors A and D are believed to play a role in capturing and stabilizing beta-tubulin intermediates in a quasi-native confirmation. Cofactor E binds to the cofactor D/beta-tubulin complex; interaction with cofactor C then causes the release of beta-tubulin polypeptides that are committed to the native state. Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

TBCE Gene-Disease associations (from GenCC):

• hypoparathyroidism-retardation-dysmorphism syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, Orphanet, G2P
• early-onset progressive diffuse brain atrophy-microcephaly-muscle weakness-optic atrophy syndrome

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• encephalopathy, progressive, with amyotrophy and optic atrophy

  Inheritance: AR Classification: STRONG, MODERATE, LIMITED Submitted by: PanelApp Australia, ClinGen, G2P, Ambry Genetics
• autosomal recessive Kenny-Caffey syndrome

  Inheritance: AR Classification: MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0532 CDS is truncated, and there are 1 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-235450286-G-A is Pathogenic according to our data. Variant chr1-235450286-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 41939.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_152490.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	B3GALNT2	NM_152490.5	MANE Select	c.1423C>T	p.Gln475*	stop_gained	Exon 12 of 12	NP_689703.1	Q8NCR0-1
	TBCE	NM_003193.5	MANE Select	c.*1524G>A		3_prime_UTR	Exon 17 of 17	NP_003184.1	Q15813-1
	TBCE	NM_001287801.2		c.*1524G>A		3_prime_UTR	Exon 18 of 18	NP_001274730.1	Q15813-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	B3GALNT2	ENST00000366600.8	TSL:1 MANE Select	c.1423C>T	p.Gln475*	stop_gained	Exon 12 of 12	ENSP00000355559.3	Q8NCR0-1
	TBCE	ENST00000642610.2	MANE Select	c.*1524G>A		3_prime_UTR	Exon 17 of 17	ENSP00000494796.1	Q15813-1
	B3GALNT2	ENST00000954792.1		c.1543C>T	p.Gln515*	stop_gained	Exon 13 of 13	ENSP00000624851.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461576 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727116

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111744

Other (OTH) AF: 0.00 AC: 0 AN: 60384

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
1	1	-	Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type a, 11 (2)
1	-	-	not provided (2)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	40
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		9.2
Vest4		0.29
GERP RS		5.4
Mutation Taster		=9/191	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs367543077; hg19: chr1-235613601;