Genetic Variant GALT:p.Arg201His (chr9-34648371-G-A) – ACMG Classification: Pathogenic (17 pts)

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PS3PM1PM5PP2PP5_Very_Strong

The NM_000155.4(GALT):c.602G>A(p.Arg201His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000217 in 1,614,212 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000820168: Experimental studies have shown that this missense change affects GALT function (PMID:11152465)." and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R201C) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000018 ( 0 hom. )

Consequence

GALT
NM_000155.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:9

Conservation

PhyloP100: 1.28

Publications

13 publications found

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 Gene-Disease associations (from GenCC):

classic galactosemia
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae)
galactosemia
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen, Myriad Women’s Health

GALT links:

ENSG00000258728 (HGNC:):

ENSG00000258728 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PS3

PS3 evidence extracted from ClinVar submissions: SCV000820168: Experimental studies have shown that this missense change affects GALT function (PMID: 11152465).; SCV002041495: GALT enzyme activity in cells obtained from a homozygous individual with this variant was <10% of normal activity. Welsink-Karssies_2020; SCV002049032: Functional studies of the variant protein have shown a mild decrease in GALT activity compared to wild type protein (Riehman 2001, Ko 2010), but GALT activity in patient erythrocytes carrying the p.Arg201His variant is more pronounced (Ko 2010, Welsink-Karssies 2020). PMID: 7887416. PMID: 20547145. PMID: 31954591.

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

PM5

Other missense variant is known to change same aminoacid residue: 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.

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.

PP5

Variant 9-34648371-G-A is Pathogenic according to our data. 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.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000155.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GALT	NM_000155.4	MANE Select	c.602G>A	p.Arg201His	missense	Exon 7 of 11	NP_000146.2
	GALT	NM_001258332.2		c.275G>A	p.Arg92His	missense	Exon 5 of 9	NP_001245261.1	P07902-2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
GALT	ENST00000378842.8	TSL:1 MANE Select	c.602G>A	p.Arg201His	missense	Exon 7 of 11	ENSP00000368119.4	P07902-1
ENSG00000258728	ENST00000556278.1	TSL:5	c.347G>A	p.Arg116His	missense	Exon 4 of 8	ENSP00000451792.1	G3V4G9
GALT	ENST00000902340.1		c.641G>A	p.Arg214His	missense	Exon 6 of 10	ENSP00000572399.1

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152210

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:

0.000827

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000239

AC:

AN:

251486

AF XY:

0.0000368

show subpopulations

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000185

AC:

AN:

1461884

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.000151

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000989

AC:

AN:

1112008

Other (OTH)

AF:

0.0000331

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000525

AC:

AN:

152328

Hom.:

Cov.:

AF XY:

0.0000671

AC XY:

AN XY:

74492

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41564

American (AMR)

AF:

0.00

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.000827

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000126

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000330

AC:

ClinVar

ClinVar submissions

Significance:Pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Deficiency of UDPglucose-hexose-1-phosphate uridylyltransferase (6)

Galactosemia (2)

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Pathogenic

0.25

BayesDel_noAF

Pathogenic

0.38

CADD

Uncertain

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.58

Eigen

Uncertain

0.26

Eigen_PC

Uncertain

0.26

FATHMM_MKL

Uncertain

0.93

LIST_S2

Benign

0.85

M_CAP

Uncertain

0.27

MetaRNN

Uncertain

0.72

MetaSVM

Pathogenic

1.1

MutationAssessor

Benign

1.8

PhyloP100

1.3

PrimateAI

Benign

0.34

PROVEAN

Uncertain

-2.6

REVEL

Pathogenic

0.74

Sift

Benign

0.037

Sift4G

Benign

0.086

Polyphen

0.98

Vest4

0.71

MutPred

0.77

Loss of phosphorylation at S205 (P = 0.1607)

MVP

0.99

MPC

0.95

ClinPred

0.54

GERP RS

4.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.26

gMVP

0.83

Mutation Taster

=24/76

disease causing (ClinVar)

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over