9-34649041-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000155.4(GALT):​c.864C>T​(p.Asn288Asn) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000026 in 1,613,992 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000092 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

GALT
NM_000155.4 synonymous

Scores

2

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: -0.186
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
GALTNM_000155.4 linkuse as main transcriptc.864C>T p.Asn288Asn synonymous_variant 9/11 ENST00000378842.8 NP_000146.2 P07902-1B2RAT6A0A0S2Z3Y7
GALTNM_001258332.2 linkuse as main transcriptc.537C>T p.Asn179Asn synonymous_variant 7/9 NP_001245261.1 P07902-2B2RAT6

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
GALTENST00000378842.8 linkuse as main transcriptc.864C>T p.Asn288Asn synonymous_variant 9/111 NM_000155.4 ENSP00000368119.4 P07902-1
ENSG00000258728ENST00000556278.1 linkuse as main transcriptc.432+585C>T intron_variant 5 ENSP00000451792.1 G3V4G9

Frequencies

GnomAD3 genomes
AF:
0.0000920
AC:
14
AN:
152118
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000290
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.0000437
AC:
11
AN:
251492
Hom.:
0
AF XY:
0.0000441
AC XY:
6
AN XY:
135922
show subpopulations
Gnomad AFR exome
AF:
0.000431
Gnomad AMR exome
AF:
0.0000578
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.0000327
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000879
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000192
AC:
28
AN:
1461874
Hom.:
0
Cov.:
32
AF XY:
0.0000261
AC XY:
19
AN XY:
727232
show subpopulations
Gnomad4 AFR exome
AF:
0.000179
Gnomad4 AMR exome
AF:
0.0000447
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.0000696
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000117
Gnomad4 OTH exome
AF:
0.0000166
GnomAD4 genome
AF:
0.0000920
AC:
14
AN:
152118
Hom.:
0
Cov.:
32
AF XY:
0.000108
AC XY:
8
AN XY:
74306
show subpopulations
Gnomad4 AFR
AF:
0.000290
Gnomad4 AMR
AF:
0.0000655
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000147
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000957
Hom.:
0
Bravo
AF:
0.000117

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase Uncertain:3
Uncertain significance, criteria provided, single submitterclinical testingCounsylMay 12, 2017- -
Uncertain significance, criteria provided, single submitterclinical testingMendelicsJun 02, 2023- -
Uncertain significance, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpMay 17, 2022This sequence change affects codon 288 of the GALT mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the GALT protein. This variant is present in population databases (rs372134800, gnomAD 0.03%). This variant has been observed in individual(s) with features of galactosemia (PMID: 22944367). ClinVar contains an entry for this variant (Variation ID: 203732). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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. -
not specified Uncertain:2
Uncertain significance, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpJul 29, 2019Variant summary: GALT c.864C>T alters a non-conserved nucleotide resulting in a synonymous change. Several computational tools predict a significant impact on normal splicing: One predict the variant strengthens a cryptic 3 acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4.4e-05 in 251692 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in GALT causing Galactosemia (4.4e-05 vs 0.0029), allowing no conclusion about variant significance. The variant, c.864C>T, has been reported in the literature in two compound heterozygous individuals affected with Galactosemia (McDonald_2009, Boutron_2012). One of these reports also noted that the diagnosis was confirmed by absent GALT activity in erythrocytes in all their cases, though no patient specific data were provided (Boutron 2012). The variant has also been reported in homozygosity in a sample from an individual that had only a residual GALT activity; and although no information was provided on the patient's phenotype, the measured enzyme activity was specific for galactosemia (Yuzyuk_2018). A conference abstract (McDonald 2009) described that cDNA containing the variant of interest (from a proband and probands father) was void of exon 9, although they both had additional variants leading to a complex haplotype (N288N, T292T and H315H) and it is not clear if the exon skipping effect was caused solely by our variant of interest or a combination effect due to this specific haplotype. These data indicate that the variant may be associated with disease. Three ClinVar submissions from other clinical diagnostic laboratories (evaluation after 2014) cited the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic until more information becomes available. -
Uncertain significance, criteria provided, single submitterclinical testingARUP Laboratories, Molecular Genetics and Genomics, ARUP LaboratoriesFeb 14, 2017- -
Galactosemia Uncertain:1
Uncertain significance, no assertion criteria providedclinical testingNatera, Inc.Sep 16, 2020- -
not provided Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingMayo Clinic Laboratories, Mayo ClinicAug 30, 2021- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.47
CADD
Benign
2.1
DANN
Benign
0.71
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.22
Details are displayed if max score is > 0.2
DS_DL_spliceai
0.22
Position offset: 40

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.

Other links and lift over

dbSNP: rs372134800; hg19: chr9-34649038; API