rs2070075

Positions:

• chr9-34648421-C-G
• chr9-34648421-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000155.4(GALT):​c.652C>G​(p.Leu218Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,870 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 Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. L218L) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GALT NM_000155.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.837

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a helix (size 11) in uniprot entity GALT_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_000155.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GALT	NM_000155.4	c.652C>G	p.Leu218Val	missense_variant	7/11	ENST00000378842.8	NP_000146.2
GALT	NM_001258332.2	c.325C>G	p.Leu109Val	missense_variant	5/9		NP_001245261.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GALT	ENST00000378842.8	c.652C>G	p.Leu218Val	missense_variant	7/11	1	NM_000155.4	ENSP00000368119	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461870 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727236

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Sep 25, 2015

- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Oct 02, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.56
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.95	.;D;.
Eigen	Uncertain	0.24
Eigen_PC	Benign	0.024
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	.;M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.45	T
PROVEAN	Uncertain	-2.9	D;D;D
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	.;D;.
Vest4		0.81
MutPred		0.95		.;Loss of glycosylation at P216 (P = 0.1164);.;
MVP		0.99
MPC		1.8
ClinPred		0.99	D
GERP RS		0.25
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.30		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.30		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs2070075; hg19: chr9-34648418;