NM_000153.4:c.583-1G>C

Variant names:

• chr14-87982244-C-G
• rs1555383310
• NM_000153.4:c.583-1G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_000153.4(GALC):​c.583-1G>C variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000701 in 1,427,424 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: GALC NM_000153.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.35
• Publications: 0 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: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.018950438 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6, offset of -25, new splice context is: ttttgtaactttcaattcAGact. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 14-87982244-C-G is Pathogenic according to our data. Variant chr14-87982244-C-G is described in ClinVar as Pathogenic. ClinVar VariationId is 556448.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GALC	NM_000153.4	c.583-1G>C		splice_acceptor_variant, intron_variant	Intron 5 of 16	ENST00000261304.7	NP_000144.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GALC	ENST00000261304.7	c.583-1G>C		splice_acceptor_variant, intron_variant	Intron 5 of 16	1	NM_000153.4	ENSP00000261304.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.01e-7 AC: 1 AN: 1427424 Hom.: 0 Cov.: 25 AF XY: 0.00000140 AC XY: 1 AN XY: 712228

African (AFR) AF: 0.00 AC: 0 AN: 32798

American (AMR) AF: 0.00 AC: 0 AN: 44428

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25822

East Asian (EAS) AF: 0.00 AC: 0 AN: 39266

South Asian (SAS) AF: 0.00 AC: 0 AN: 85228

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53276

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5704

European-Non Finnish (NFE) AF: 9.24e-7 AC: 1 AN: 1081704

Other (OTH) AF: 0.00 AC: 0 AN: 59198

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Galactosylceramide beta-galactosidase deficiency Pathogenic:2

Dec 01, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Disruption of this splice site has been observed in individual(s) with Krabbe disease (PMID: 26108647, 26795590). ClinVar contains an entry for this variant (Variation ID: 556448). This sequence change affects an acceptor splice site in intron 5 of the GALC gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in GALC are known to be pathogenic (PMID: 7437911, 9272171, 16607461). This variant is not present in population databases (ExAC no frequency). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. For these reasons, this variant has been classified as Pathogenic. -

Jan 31, 2018

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.3
GERP RS		5.0
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.96		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1555383310; hg19: chr14-88448588;