rs111033847

chr9-34648877-C-Achr9-34648877-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000155.4(GALT):c.803C>A(p.Thr268Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,613,140 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. T268T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000021 (0 hom.)
• Consequence: GALT NM_000155.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.19

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000155.4
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GALT	NM_000155.4	c.803C>A	p.Thr268Asn	missense_variant	8/11	ENST00000378842.8
GALT	NM_001258332.2	c.476C>A	p.Thr159Asn	missense_variant	6/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GALT	ENST00000378842.8	c.803C>A	p.Thr268Asn	missense_variant	8/11	1	NM_000155.4	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152162 Hom.: 0 Cov.: 32

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 250796 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135648

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000440

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000205 AC: 30 AN: 1460978 Hom.: 0 Cov.: 32 AF XY: 0.0000165 AC XY: 12 AN XY: 726874

Gnomad4 AFR exome AF: 0.0000598

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000216

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152162 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74332

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: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000388 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 07, 2022

This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 268 of the GALT protein (p.Thr268Asn). This variant is present in population databases (rs111033847, gnomAD 0.004%). This missense change has been observed in individual(s) with clinical features of GALT-related conditions (PMID: 18210213). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Uncertain	0.087	D
BayesDel_noAF	Uncertain	0.020
Cadd	Benign	19
Dann	Benign	0.96
Eigen	Benign	-0.26
Eigen_PC	Benign	-0.13
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.83	T;T
M_CAP	Uncertain	0.19	D
MetaRNN	Uncertain	0.46	T;T
MetaSVM	Uncertain	0.78	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-2.5	D;N
REVEL	Uncertain	0.59
Sift	Benign	0.35	T;T
Sift4G	Benign	0.36	T;T
Polyphen		0.0020	.;B
Vest4		0.41
MVP		0.93
MPC		0.88
ClinPred		0.054	T
GERP RS		2.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.15
gMVP		0.84

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

LitVar

Other links and lift over

dbSNP: rs111033847; hg19: chr9-34648874;