rs118204439

Positions:

• chr16-88818072-G-A
• chr16-88818072-G-C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000512.5(GALNS):​c.1417C>T​(p.Gln473*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000141 in 1,422,114 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 Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: GALNS NM_000512.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 1.14

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]

GALNS (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 4 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-88818072-G-A is Pathogenic according to our data. Variant chr16-88818072-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 704.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.1417C>T	p.Gln473*	stop_gained	13/14	ENST00000268695.10	NP_000503.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GALNS	ENST00000268695.10	c.1417C>T	p.Gln473*	stop_gained	13/14	1	NM_000512.5	ENSP00000268695.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000141 AC: 2 AN: 1422114 Hom.: 0 Cov.: 34 AF XY: 0.00000142 AC XY: 1 AN XY: 704804

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: 0.0000240

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000169

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000689 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Mucopolysaccharidosis, MPS-IV-A Pathogenic:3

Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 01, 1995	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 19, 2022	This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln473*) in the GALNS gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GALNS are known to be pathogenic (PMID: 12442278). This premature translational stop signal has been observed in individual(s) with mucopolysaccharidosis type IVA (PMID: 7581409, 33752727). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 704). -
Pathogenic, criteria provided, single submitter	curation	Laboratory of Diagnosis and Therapy of Lysosomal Disorders, University of Padova	Feb 01, 2021	Nonsense variant (PVS1_very strong); in vivo functional studies supportive of a damaging effect on the gene product (low to null enzymatic activity in homozygotes; PS3_supporting); 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	0.46
CADD	Pathogenic	41
DANN	Uncertain	1.0
Eigen	Uncertain	0.55
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Benign	0.34	N
Vest4		0.81
GERP RS		4.1

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: rs118204439; hg19: chr16-88884480;