NM_000155.4:c.601C>T

Variant names:

• chr9-34648370-C-T
• rs111033739
• NM_000155.4:c.601C>T

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Very_Strong

The NM_000155.4(GALT):​c.601C>T​(p.Arg201Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000805 in 1,614,168 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. R201H) has been classified as Pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: GALT NM_000155.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 0.831
• Publications: 7 publications found

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

ENSG00000258728 (HGNC:):

ACMG classification

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

• PM1: In a hotspot region, there are 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 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 chr9-34648371-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 25227.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• 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, 0.92
• PP5: Variant 9-34648370-C-T is Pathogenic according to our data. Variant chr9-34648370-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 25226.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	c.601C>T	p.Arg201Cys	missense_variant	Exon 7 of 11	ENST00000378842.8	NP_000146.2
GALT	NM_001258332.2	c.274C>T	p.Arg92Cys	missense_variant	Exon 5 of 9		NP_001245261.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GALT	ENST00000378842.8	c.601C>T	p.Arg201Cys	missense_variant	Exon 7 of 11	1	NM_000155.4	ENSP00000368119.4
ENSG00000258728	ENST00000556278.1	c.346C>T	p.Arg116Cys	missense_variant	Exon 4 of 8	5		ENSP00000451792.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152168 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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251482 AF XY: 0.0000147

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461882 Hom.: 0 Cov.: 33 AF XY: 0.00000688 AC XY: 5 AN XY: 727242

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000504 AC: 2 AN: 39700

South Asian (SAS) AF: 0.0000348 AC: 3 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152286 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74466

African (AFR) AF: 0.00 AC: 0 AN: 41546

American (AMR) AF: 0.00 AC: 0 AN: 15300

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5178

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68018

Other (OTH) AF: 0.00 AC: 0 AN: 2110

Alfa AF: 0.00000469 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase Pathogenic:4

Mar 23, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 21, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant is present in population databases (rs111033739, gnomAD 0.006%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 201 of the GALT protein (p.Arg201Cys). This missense change has been observed in individual(s) with galactosemia (PMID: 17876724, 28644047; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 25226). 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. Experimental studies have shown that this missense change affects GALT function (PMID: 22461411). This variant disrupts the p.Arg201 amino acid residue in GALT. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11152465, 20547145; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. -

Sep 23, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 27, 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.601C>T (p.Arg201Cys) results in a non-conservative amino acid change in 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 251482 control chromosomes (gnomAD). c.601C>T has been reported in the literature in individuals affected with Galactosemia (Calderon_2007, Schulpis_2017, Yuzyuk_2018). These data indicate that the variant is likely to be associated with disease. Experimental evidence evaluating an impact on protein function demonstrated the variant affects enzyme function (Tang_2012). A different variant affecting the same amino acid residue (c.602G>A, p.Arg201His) has been classified as pathogenic by our laboratory. The following publications have been ascertained in the context of this evaluation (PMID: 17876724, 28644047, 22461411, 30172461). Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

not provided Pathogenic:2

Feb 03, 2025

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 20008339, 30172461, 20547145, 11152465, 28644047, 22461411, 35692825, 17876724) -

Feb 09, 2017

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified Pathogenic:1

Feb 14, 2017

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Galactosemia Pathogenic:1

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.42
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.76	.;D;.
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.87	D;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.92	D;D;D
MetaSVM	Pathogenic	1.2	D
MutationAssessor	Uncertain	2.4	.;M;.
PhyloP100		0.83
PrimateAI	Benign	0.37	T
PROVEAN	Uncertain	-3.4	D;D;N
REVEL	Pathogenic	0.86
Sift	Uncertain	0.022	D;D;T
Sift4G	Uncertain	0.033	D;D;T
Polyphen		1.0	.;D;.
Vest4		0.78
MutPred		0.83		.;Loss of disorder (P = 0.0483);.;
MVP		0.99
MPC		2.0
ClinPred		0.95	D
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.45
gMVP		0.89
Mutation Taster		=21/79	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs111033739; hg19: chr9-34648367;