14-87941455-C-T

Variant names:

• chr14-87941455-C-T
• rs1360345372
• NM_000153.4:c.1774G>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_000153.4(GALC):​c.1774G>A​(p.Ala592Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,457,310 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. A592S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GALC NM_000153.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.63
• Publications: 3 publications found

Genes affected

GALC (HGNC:4115): (galactosylceramidase) This gene encodes a lysosomal protein which hydrolyzes the galactose ester bonds of galactosylceramide, galactosylsphingosine, lactosylceramide, and monogalactosyldiglyceride. Mutations in this gene have been associated with Krabbe disease, also known as globoid cell leukodystrophy. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. [provided by RefSeq, Jul 2008]

GALC Gene-Disease associations (from GenCC):

• Krabbe disease

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Myriad Women’s Health, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), PanelApp Australia, ClinGen, Genomics England PanelApp

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000153.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 94 curated pathogenic missense variants (we use a threshold of 10). The gene has 16 curated benign missense variants. Gene score misZ: 0.18582 (below the threshold of 3.09). Trascript score misZ: -0.28853 (below the threshold of 3.09). GenCC associations: The gene is linked to Krabbe disease.
• BP4: Computational evidence support a benign effect (MetaRNN=0.26529133).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GALC	NM_000153.4	c.1774G>A	p.Ala592Thr	missense_variant	Exon 15 of 17	ENST00000261304.7	NP_000144.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GALC	ENST00000261304.7	c.1774G>A	p.Ala592Thr	missense_variant	Exon 15 of 17	1	NM_000153.4	ENSP00000261304.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1457310 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 725194

African (AFR) AF: 0.00 AC: 0 AN: 33336

American (AMR) AF: 0.0000224 AC: 1 AN: 44664

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26034

East Asian (EAS) AF: 0.00 AC: 0 AN: 39636

South Asian (SAS) AF: 0.00 AC: 0 AN: 86156

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53322

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5742

European-Non Finnish (NFE) AF: 9.02e-7 AC: 1 AN: 1108206

Other (OTH) AF: 0.00 AC: 0 AN: 60214

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Galactosylceramide beta-galactosidase deficiency Uncertain:1

Jan 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 592 of the GALC protein (p.Ala592Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GALC-related conditions. 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 not expected to disrupt GALC protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	20
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.65	D;.;.;.
Eigen	Benign	-0.041
Eigen_PC	Benign	0.10
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.86	D;D;D;D
M_CAP	Benign	0.043	D
MetaRNN	Benign	0.27	T;T;T;T
MetaSVM	Uncertain	0.16	D
MutationAssessor	Uncertain	2.1	M;.;.;.
PhyloP100		2.6
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-1.3	N;N;N;N
REVEL	Uncertain	0.32
Sift	Benign	0.24	T;T;T;T
Sift4G	Benign	0.68	T;T;T;T
Polyphen		0.54	P;B;B;.
Vest4		0.12
MutPred		0.72		Gain of catalytic residue at R590 (P = 0);.;.;.;
MVP		0.92
MPC		0.32
ClinPred		0.90	D
GERP RS		4.8
Varity_R		0.078
gMVP		0.81
Mutation Taster		=77/23	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1360345372; hg19: chr14-88407799;