9-34648888-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM2PM5PP2PP3_ModeratePP5_Very_Strong

The NM_000155.4(GALT):c.814C>T(p.Arg272Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,613,164 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R272L) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

GALT
NM_000155.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5U:1

Conservation

PhyloP100: 0.754

Publications

5 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

GALT links:

ENSG00000258728 (HGNC:):

ENSG00000258728 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 17 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000155.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr9-34648889-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1993890.

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, 0.936

PP5

Variant 9-34648888-C-T is Pathogenic according to our data. Variant chr9-34648888-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 550184.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GALT	NM_000155.4 link	c.814C>T	p.Arg272Cys	missense_variant	Exon 8 of 11	ENST00000378842.8	NP_000146.2
GALT	NM_001258332.2 link	c.487C>T	p.Arg163Cys	missense_variant	Exon 6 of 9		NP_001245261.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GALT	ENST00000378842.8 link	c.814C>T	p.Arg272Cys	missense_variant	Exon 8 of 11	1	NM_000155.4	ENSP00000368119.4
ENSG00000258728	ENST00000556278.1 link	c.432+432C>T		intron_variant	Intron 4 of 7	5		ENSP00000451792.1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152186

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

GnomAD2 exomes

AF:

0.00000798

AC:

AN:

250770

AF XY:

0.00000737

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1460978

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726854

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52664

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5662

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111996

Other (OTH)

AF:

0.00

AC:

AN:

60376

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152186

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74336

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41438

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase

Pathogenic:3Uncertain:1

Jan 31, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: GALT c.814C>T (p.Arg272Cys) results in a non-conservative amino acid change located in the C-terminal domain (IPR005850) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 250770 control chromosomes (gnomAD). c.814C>T has been reported in the literature in the compound heterozygous state in trans with a pathogenic variant (p.Q188R) in three unrelated individuals affected with Galactosemia (Ounap_2010). These data indicate that the variant is likely associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Two laboratories classified it as pathogenic (n=1)/likely pathogenic (n=1), and one classified it as VUS. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 04, 2017

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Nov 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 272 of the GALT protein (p.Arg272Cys). This variant is present in population databases (rs111033766, gnomAD 0.008%). This missense change has been observed in individuals with autosomalrecessive galactosemia (PMID: 20151200). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 550184). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt GALT protein function with a positive predictive value of 95%. This variant disrupts the p.Arg272 amino acid residue in GALT. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 22944367). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

GALT-related disorder

Pathogenic:1

Sep 10, 2022

PreventionGenetics, part of Exact Sciences

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The GALT c.814C>T variant is predicted to result in the amino acid substitution p.Arg272Cys. This variant has been reported in the compound heterozygous state with a known pathogenic GALT variant in at least three individuals with classic galactosemia (Ounap et al. 2010. PubMed ID: 20151200; Krabbi et al. 2011. PubMed ID: 21501963). An alternate substitution impacting the same amino acid (p.Arg272His) has been reported along with a second GALT variant in patients with galactosemia (e.g., Boutron et al. 2012. PubMed ID: 22944367). The c.814C>T (p.Arg272Cys) variant is reported in 0.0080% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/9-34648885-C-T). Based on the collective evidence, this variant is interpreted as likely pathogenic. -

Galactosemia

Pathogenic:1

Dec 27, 2020

Natera, Inc.

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.33

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.54

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.96

.;D

Eigen

Pathogenic

0.76

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Uncertain

0.96

LIST_S2

Pathogenic

1.0

D;D

M_CAP

Pathogenic

0.76

MetaRNN

Pathogenic

0.94

D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

4.0

.;H

PhyloP100

0.75

PrimateAI

Uncertain

0.59

PROVEAN

Pathogenic

-6.5

D;D

REVEL

Pathogenic

0.92

Sift

Pathogenic

0.0

D;D

Sift4G

Uncertain

0.0020

D;D

Polyphen

1.0

.;D

Vest4

0.67

MVP

1.0

MPC

2.1

ClinPred

1.0

GERP RS

5.8

Varity_R

0.93

gMVP

0.96

Mutation Taster

=3/97

disease causing (ClinVar)

(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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over