NM_006876.3:c.447G>C

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBS1_Supporting

The NM_006876.3(B4GAT1):c.447G>C(p.Met149Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000195 in 1,582,022 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00020 ( 0 hom. )

Consequence

B4GAT1
NM_006876.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 1.32

Publications

0 publications found

Variant links:

Genes affected

B4GAT1 (HGNC:15685): (beta-1,4-glucuronyltransferase 1) This gene encodes a member of the beta-1,3-N-acetylglucosaminyltransferase family. This enzyme is a type II transmembrane protein. It is essential for the synthesis of poly-N-acetyllactosamine, a determinant for the blood group i antigen. [provided by RefSeq, Jul 2008]

B4GAT1 Gene-Disease associations (from GenCC):

muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A13
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
muscular dystrophy-dystroglycanopathy, type A
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

B4GAT1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.031127453).

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000118 (18/152240) while in subpopulation NFE AF = 0.000191 (13/68036). AF 95% confidence interval is 0.000112. There are 0 homozygotes in GnomAd4. There are 8 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
B4GAT1	NM_006876.3 link	c.447G>C	p.Met149Ile	missense_variant	Exon 1 of 2	ENST00000311181.5	NP_006867.1	O43505A0A024R5F9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
B4GAT1	ENST00000311181.5 link	c.447G>C	p.Met149Ile	missense_variant	Exon 1 of 2	1	NM_006876.3	ENSP00000309096.4		O43505

Frequencies

GnomAD3 genomes

AF:

0.000118

AC:

AN:

152240

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000964

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.000191

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000477

AC:

AN:

209752

AF XY:

0.0000522

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000107

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000203

AC:

290

AN:

1429782

Hom.:

Cov.:

AF XY:

0.000203

AC XY:

144

AN XY:

708096

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32954

American (AMR)

AF:

0.00

AC:

AN:

42216

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24464

East Asian (EAS)

AF:

0.00

AC:

AN:

38948

South Asian (SAS)

AF:

0.00

AC:

AN:

82274

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48108

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5650

European-Non Finnish (NFE)

AF:

0.000260

AC:

285

AN:

1096206

Other (OTH)

AF:

0.0000848

AC:

AN:

58962

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

103

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

100

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000118

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74380

show subpopulations

African (AFR)

AF:

0.0000964

AC:

AN:

41476

American (AMR)

AF:

0.0000654

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000191

AC:

AN:

68036

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.494

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000784

Hom.:

Bravo

AF:

0.0000756

TwinsUK

AF:

0.000539

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.0000584

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Dec 28, 2021

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 21, 2020

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Inborn genetic diseases

Uncertain:1

Jul 05, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.447G>C (p.M149I) alteration is located in exon 1 (coding exon 1) of the B4GAT1 gene. This alteration results from a G to C substitution at nucleotide position 447, causing the methionine (M) at amino acid position 149 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A13

Uncertain:1

Nov 08, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 149 of the B4GAT1 protein (p.Met149Ile). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with B4GAT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 577279). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The isoleucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.19

BayesDel_addAF

Benign

-0.41

BayesDel_noAF

Benign

-0.61

CADD

Benign

(source)

DANN

Benign

0.88

DEOGEN2

Benign

0.15

Eigen

Benign

-0.69

Eigen_PC

Benign

-0.41

FATHMM_MKL

Benign

0.63

LIST_S2

Benign

0.67

M_CAP

Benign

0.0055

MetaRNN

Benign

0.031

MetaSVM

Benign

-0.99

PhyloP100

1.3

PrimateAI

Uncertain

0.62

PROVEAN

Benign

1.6

REVEL

Benign

0.060

Sift

Benign

0.81

Sift4G

Benign

0.91

Polyphen

0.0

Vest4

0.12

MutPred

0.43

Loss of disorder (P = 0.0727);

MVP

0.014

MPC

0.92

ClinPred

0.043

GERP RS

3.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.19

gMVP

0.75

Mutation Taster

=80/20

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over