chr1-161172040-T-G

Variant names:

• chr1-161172040-T-G
• NM_003779.4:c.958A>C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_003779.4(B4GALT3):​c.958A>C​(p.Asn320His) variant causes a missense change. 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 (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: B4GALT3 NM_003779.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.90

Genes affected

B4GALT3 (HGNC:926): (beta-1,4-galactosyltransferase 3) This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have exclusive specificity for the donor substrate UDP-galactose; all transfer galactose in a beta1,4 linkage to similar acceptor sugars: GlcNAc, Glc, and Xyl. Each beta4GalT has a distinct function in the biosynthesis of different glycoconjugates and saccharide structures. As type II membrane proteins, they have an N-terminal hydrophobic signal sequence that directs the protein to the Golgi apparatus and which then remains uncleaved to function as a transmembrane anchor. By sequence similarity, the beta4GalTs form four groups: beta4GalT1 and beta4GalT2, beta4GalT3 and beta4GalT4, beta4GalT5 and beta4GalT6, and beta4GalT7. This gene encodes an enzyme that may be mainly involved in the synthesis of the first N-acetyllactosamine unit of poly-N-acetyllactosamine chains. Multiple alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Dec 2010]

PPOX (HGNC:9280): (protoporphyrinogen oxidase) This gene encodes the penultimate enzyme of heme biosynthesis, which catalyzes the 6-electron oxidation of protoporphyrinogen IX to form protoporphyrin IX. Mutations in this gene cause variegate porphyria, an autosomal dominant disorder of heme metabolism resulting from a deficiency in protoporphyrinogen oxidase, an enzyme located on the inner mitochondrial membrane. Alternatively spliced transcript variants encoding the same protein have been identified. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.784

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
B4GALT3	NM_003779.4	c.958A>C	p.Asn320His	missense_variant	Exon 8 of 8	ENST00000319769.10	NP_003770.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
B4GALT3	ENST00000319769.10	c.958A>C	p.Asn320His	missense_variant	Exon 8 of 8	1	NM_003779.4	ENSP00000320965.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Sep 10, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.958A>C (p.N320H) alteration is located in exon 8 (coding exon 6) of the B4GALT3 gene. This alteration results from a A to C substitution at nucleotide position 958, causing the asparagine (N) at amino acid position 320 to be replaced by a histidine (H). 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	Uncertain	0.50
BayesDel_addAF	Benign	0.0065	T
BayesDel_noAF	Benign	-0.23
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.29	T;T;T
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	.;D;.
M_CAP	Benign	0.047	D
MetaRNN	Pathogenic	0.78	D;D;D
MetaSVM	Benign	-0.66	T
PrimateAI	Uncertain	0.63	T
PROVEAN	Uncertain	-4.3	D;.;D
REVEL	Uncertain	0.51
Sift	Uncertain	0.0020	D;.;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.57
MutPred		0.72		Gain of catalytic residue at N320 (P = 0.0068);Gain of catalytic residue at N320 (P = 0.0068);Gain of catalytic residue at N320 (P = 0.0068);
MVP		0.76
MPC		1.2
ClinPred		0.98	D
GERP RS		5.3
Varity_R		0.62
gMVP		0.92

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-161141830;