NM_000155.4:c.1018G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PP2PP3_StrongPP5

The NM_000155.4(GALT):​c.1018G>A​(p.Glu340Lys) variant causes a missense change. The variant allele was found at a frequency of 0.0000197 in 152,304 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).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)

Consequence

GALT
NM_000155.4 missense

Scores

15
1
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3

Conservation

PhyloP100: 5.17

Publications

12 publications found
Variant links:
Genes affected
GALT (HGNC:4135): (galactose-1-phosphate uridylyltransferase) Galactose-1-phosphate uridyl transferase (GALT) catalyzes the second step of the Leloir pathway of galactose metabolism, namely the conversion of UDP-glucose + galactose-1-phosphate to glucose-1-phosphate + UDP-galactose. The absence of this enzyme results in classic galactosemia in humans and can be fatal in the newborn period if lactose is not removed from the diet. The pathophysiology of galactosemia has not been clearly defined. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]
GALT Gene-Disease associations (from GenCC):
  • classic galactosemia
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Orphanet
  • galactosemia
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen, Myriad Women’s Health

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PM1
In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000155.4
PM2
Very rare variant in population databases, with high coverage;
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 104 curated pathogenic missense variants (we use a threshold of 10). The gene has 17 curated benign missense variants. Gene score misZ: 0.91493 (below the threshold of 3.09). Trascript score misZ: 1.8645 (below the threshold of 3.09). GenCC associations: The gene is linked to galactosemia, classic galactosemia.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.992
PP5
Variant 9-34649523-G-A is Pathogenic according to our data. Variant chr9-34649523-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 25317.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GALTNM_000155.4 linkc.1018G>A p.Glu340Lys missense_variant Exon 10 of 11 ENST00000378842.8 NP_000146.2
GALTNM_001258332.2 linkc.691G>A p.Glu231Lys missense_variant Exon 8 of 9 NP_001245261.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GALTENST00000378842.8 linkc.1018G>A p.Glu340Lys missense_variant Exon 10 of 11 1 NM_000155.4 ENSP00000368119.4
ENSG00000258728ENST00000556278.1 linkc.432+1067G>A intron_variant Intron 4 of 7 5 ENSP00000451792.1

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152186
Hom.:
0
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.0000483
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD4 exome
Cov.:
31
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152304
Hom.:
0
Cov.:
31
AF XY:
0.0000134
AC XY:
1
AN XY:
74484
show subpopulations
African (AFR)
AF:
0.0000481
AC:
2
AN:
41566
American (AMR)
AF:
0.00
AC:
0
AN:
15306
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3466
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5182
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68018
Other (OTH)
AF:
0.00
AC:
0
AN:
2112
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000329
Hom.:
0
Bravo
AF:
0.0000302

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:3
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase Pathogenic:1Uncertain:1
Oct 21, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 340 of the GALT protein (p.Glu340Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with GALT-related conditions (PMID: 10649501, 20213376, 22944367, 28065439). ClinVar contains an entry for this variant (Variation ID: 25317). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GALT 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.

Jun 12, 2023
Baylor Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

not specified Uncertain:1
Aug 26, 2021
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: GALT c.1018G>A (p.Glu340Lys) results in a conservative amino acid change located in the Galactose-1-phosphate uridyl transferase, C-terminal domain of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251462 control chromosomes. c.1018G>A has been reported in the literature in individuals affected with Galactosemia in the homozygous and compound heterozygous state with the Duarte allele in cis (Kozak_2000, Milankovics_2010), the compound heterozygous without reporting the of presence of Duarte allele (Siripunthana_2013) and in the heterozygous state without a reported second allele and unknown Duarte allele status (Welling_2017). The penetrance of the variant in isolation is unknown. Additionally, to our knowledge, no experimental studies have been performed on this variant in isolation. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic.

Galactosemia Uncertain:1
Aug 10, 2021
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.99
BayesDel_addAF
Pathogenic
0.56
D
BayesDel_noAF
Pathogenic
0.56
CADD
Pathogenic
33
DANN
Pathogenic
1.0
DEOGEN2
Benign
0.0
.;D
Eigen
Pathogenic
1.0
Eigen_PC
Pathogenic
0.95
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
1.0
D;D
M_CAP
Pathogenic
0.80
D
MetaRNN
Pathogenic
0.99
D;D
MetaSVM
Pathogenic
0.99
D
MutationAssessor
Benign
0.0
.;H
PhyloP100
5.2
PrimateAI
Pathogenic
0.91
D
PROVEAN
Uncertain
-3.9
D;D
REVEL
Pathogenic
0.98
Sift
Pathogenic
0.0
D;D
Sift4G
Pathogenic
0.0010
D;D
Vest4
0.95
ClinPred
1.0
D
GERP RS
5.2
Varity_R
0.99
gMVP
0.96
Mutation Taster
=4/96
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.060
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs111033806; hg19: chr9-34649520; COSMIC: COSV58840206; COSMIC: COSV58840206; API