17-75765055-G-A

Position:

• chr17-75765055-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PM5 PP3

The ENST00000588479.6(GALK1):​c.82C>T​(p.Pro28Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000207 in 1,452,088 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P28T) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GALK1 ENST00000588479.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.87

Genes affected

GALK1 (HGNC:4118): (galactokinase 1) Galactokinase is a major enzyme for the metabolism of galactose and its deficiency causes congenital cataracts during infancy and presenile cataracts in the adult population. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-75765055-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 5630.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.782

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GALK1	NM_000154.2	c.82C>T	p.Pro28Ser	missense_variant	1/8	ENST00000588479.6	NP_000145.1
GALK1	NM_001381985.1	c.82C>T	p.Pro28Ser	missense_variant	1/9		NP_001368914.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GALK1	ENST00000588479.6	c.82C>T	p.Pro28Ser	missense_variant	1/8	1	NM_000154.2	ENSP00000465930	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000207 AC: 3 AN: 1452088 Hom.: 0 Cov.: 31 AF XY: 0.00000416 AC XY: 3 AN XY: 721712

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: 0.00000271

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Deficiency of galactokinase Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 10, 2022

This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 28 of the GALK1 protein (p.Pro28Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GALK1-related conditions. 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. This variant disrupts the p.Pro28 amino acid residue in GALK1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10521295, 10790206, 11978883, 11978884, 12647253, 21290184). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 1015448). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.55
BayesDel_addAF	Uncertain	0.047	T
BayesDel_noAF	Benign	-0.17
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D;D
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.42
FATHMM_MKL	Benign	0.72	D
LIST_S2	Benign	0.84	.;T
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.78	D;D
MetaSVM	Pathogenic	0.83	D
MutationAssessor	Uncertain	2.9	M;M
MutationTaster	Benign	0.99	D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Uncertain	-4.2	D;.
REVEL	Pathogenic	0.65
Sift	Uncertain	0.018	D;.
Sift4G	Uncertain	0.0070	D;D
Polyphen		1.0	D;D
Vest4		0.46
MutPred		0.72		Gain of phosphorylation at P28 (P = 0.03);Gain of phosphorylation at P28 (P = 0.03);
MVP		0.96
MPC		0.69
ClinPred		0.99	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.93
gMVP		0.88

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

LitVar

Other links and lift over

dbSNP: rs104894572; hg19: chr17-73761136;