rs767329054

chr17-75763384-AC-Achr17-75763384-AC-ACC

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000154.2(GALK1):c.410del(p.Gly137ValfsTer27) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,460,956 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: GALK1 NM_000154.2 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 7.54

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 Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-75763384-AC-A is Pathogenic according to our data. Variant chr17-75763384-AC-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 552633.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GALK1	NM_000154.2	c.410del	p.Gly137ValfsTer27	frameshift_variant	3/8	ENST00000588479.6
GALK1	NM_001381985.1	c.410del	p.Gly137ValfsTer27	frameshift_variant	3/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GALK1	ENST00000588479.6	c.410del	p.Gly137ValfsTer27	frameshift_variant	3/8	1	NM_000154.2	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460956 Hom.: 0 Cov.: 37 AF XY: 0.00000275 AC XY: 2 AN XY: 726756

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: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Deficiency of galactokinase Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Sep 17, 2018	The p.Gly137ValfsX27 variant in GALK1 has been reported in the homozygous state in 6 affected members of one Pakistani family with early-onset cataracts (Yasmeen 2010). It was absent from large population studies. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 137 and leads to a premature termination codon 27 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. In summary, this variant meets criteria to be classified as pathogenic for galactokinase deficiency in an autosomal recessive manner. ACMG/AMP criteria applied: PVS1_Strong, PP1_Strong, PM2, PM3_Supporting. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jun 27, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 28, 2024	This sequence change creates a premature translational stop signal (p.Gly137Valfs*27) in the GALK1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GALK1 are known to be pathogenic (PMID: 7670469, 10790206). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with GALK1-related conditions (PMID: 10570908, 20405025). ClinVar contains an entry for this variant (Variation ID: 552633). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	Jan 03, 2022	Frameshift: predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant (PVS1_VS). The variant has been reported at least twice as pathogenic/likely pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000552633, PMID:10570908). It is not observed in the gnomAD v2.1.1 dataset (PM2_M). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Mar 13, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 06, 2023	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Jul 01, 2023

GALK1: PVS1, PM2, PM3, PP4 -

Computational scores

Source: dbNSFP v4.3

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: rs767329054; hg19: chr17-73759465;