rs111033667

Variant summary

Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1PM2PP3_StrongPP5_Very_Strong

The NM_000155.4(GALT):c.329-2A>C variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000173 in 1,614,010 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000018 ( 0 hom. )

Consequence

GALT
NM_000155.4 splice_acceptor

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.55

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 22 ACMG points.

PVS1

Splicing variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.8, offset of 7, new splice context is: tcctttacctccggacccAGtga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

PP5

Variant 9-34647655-A-C is Pathogenic according to our data. Variant chr9-34647655-A-C is described in ClinVar as [Pathogenic]. Clinvar id is 25154.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GALT	NM_000155.4 linkuse as main transcript	c.329-2A>C		splice_acceptor_variant		ENST00000378842.8
GALT	NM_001258332.2 linkuse as main transcript	c.51-177A>C		intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GALT	ENST00000378842.8 linkuse as main transcript	c.329-2A>C		splice_acceptor_variant		1	NM_000155.4	P1	P07902-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152132

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251452

Hom.:

AF XY:

0.0000294

AC XY:

AN XY:

135902

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000178

AC:

AN:

1461878

Hom.:

Cov.:

AF XY:

0.0000193

AC XY:

AN XY:

727242

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000225

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152132

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74320

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000322

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase

Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jan 21, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 24, 2018	Variant summary: GALT c.329-2A>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Five predict the variant abolishes a 3' acceptor site. These predictions are supported by the evidence that patient with homozygous allele has no measurable GALT activity (Zekanowsko_1999). The variant allele was found at a frequency of 2e-05 in 246254 control chromosomes. c.329-2A>C has been reported in the literature in multiple individuals affected with Galactosemia (Elsas_1995, Zekanowski_1999, Zekanowski_2001, Boutron_2012, Bosch_2005). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in unmeasurable activity (Zekanowski_1999). Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Oct 19, 2023	This sequence change affects an acceptor splice site in intron 3 of the GALT gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in GALT are known to be pathogenic (PMID: 22944367). This variant is present in population databases (rs111033667, gnomAD 0.007%). Disruption of this splice site has been observed in individuals with galactosemia (PMID: 7887416, 10399107). This variant is also known as IVS3nt-2A>C. ClinVar contains an entry for this variant (Variation ID: 25154). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Apr 24, 2023	PM2, PM3, PS4_moderate, PVS1 -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	May 25, 2021	Canonical splice site variant predicted to result in a null allele in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 7887416, 10399107, 22944367, 25525159) -

Galactosemia

Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Natera, Inc.

Aug 29, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.50

BayesDel_noAF

Uncertain

0.040

Cadd

Pathogenic

Dann

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.94

FATHMM_MKL

Pathogenic

0.98

MutationTaster

Benign

1.0

A;A

GERP RS

5.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.92

SpliceAI score (max)

0.41

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.41

Position offset: 2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over