16-88835212-C-G

Position:

• chr16-88835212-C-G

Variant summary

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

The NM_000512.5(GALNS):​c.898+1G>C variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,180 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 Likely pathogenic (★★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: GALNS NM_000512.5 splice_donor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 7.71

Genes affected

GALNS (HGNC:4122): (galactosamine (N-acetyl)-6-sulfatase) This gene encodes N-acetylgalactosamine-6-sulfatase which is a lysosomal exohydrolase required for the degradation of the glycosaminoglycans, keratan sulfate, and chondroitin 6-sulfate. Sequence alterations including point, missense and nonsense mutations, as well as those that affect splicing, result in a deficiency of this enzyme. Deficiencies of this enzyme lead to Morquio A syndrome, a lysosomal storage disorder. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-88835212-C-G is Pathogenic according to our data. Variant chr16-88835212-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 224783.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GALNS	NM_000512.5	c.898+1G>C		splice_donor_variant		ENST00000268695.10	NP_000503.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GALNS	ENST00000268695.10	c.898+1G>C		splice_donor_variant		1	NM_000512.5	ENSP00000268695	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152180 Hom.: 0 Cov.: 32

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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152180 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74340

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Mucopolysaccharidosis, MPS-IV-A Pathogenic:2 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 10, 2023	ClinVar contains an entry for this variant (Variation ID: 224783). Disruption of this splice site has been observed in individuals with mucopolysaccharidosis type IVA (PMID: 9298823, 15235041). This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 8 of the GALNS 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 GALNS are known to be pathogenic (PMID: 12442278). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
not provided, no classification provided	literature only	GeneReviews	-	- -
Likely pathogenic, criteria provided, single submitter	curation	Laboratory of Diagnosis and Therapy of Lysosomal Disorders, University of Padova	Feb 01, 2021	Splicing variant in canonical site (PVS1_very strong); absent from gnomAD v2.1.1 (PM2_moderate) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.15
CADD	Pathogenic	27
DANN	Uncertain	0.99
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs761850746; hg19: chr16-88901620;