Genetic Variant GALNS:p.Tyr181Phe (chr16-88837646-T-A) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PM5

The NM_000512.5(GALNS):c.542A>T(p.Tyr181Phe) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,484 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y181C) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GALNS
NM_000512.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 5.94

Publications

0 publications found

Variant links:

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 Gene-Disease associations (from GenCC):

mucopolysaccharidosis type 4A
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, ClinGen, Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp

GALNS links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000512.5

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr16-88837646-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 192298.We mark this variant Likely_pathogenic, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GALNS	NM_000512.5 link	c.542A>T	p.Tyr181Phe	missense_variant	Exon 5 of 14	ENST00000268695.10	NP_000503.1	P34059Q96I49

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GALNS	ENST00000268695.10 link	c.542A>T	p.Tyr181Phe	missense_variant	Exon 5 of 14	1	NM_000512.5	ENSP00000268695.5		P34059

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461484

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727070

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86238

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53270

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5586

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111988

Other (OTH)

AF:

0.00

AC:

AN:

60370

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Uncertain

0.11

BayesDel_noAF

Uncertain

-0.080

CADD

Benign

(source)

DANN

Uncertain

0.98

DEOGEN2

Uncertain

0.69

D;.

Eigen

Benign

-0.085

Eigen_PC

Benign

-0.025

FATHMM_MKL

Uncertain

0.88

LIST_S2

Uncertain

0.95

D;D

M_CAP

Pathogenic

0.31

MetaRNN

Uncertain

0.53

D;D

MetaSVM

Uncertain

0.12

MutationAssessor

Benign

0.67

N;.

PhyloP100

5.9

PrimateAI

Uncertain

0.61

PROVEAN

Benign

-1.5

N;N

REVEL

Uncertain

0.51

Sift

Benign

0.16

T;T

Sift4G

Benign

0.39

T;.

Polyphen

0.95

P;.

Vest4

0.50

MutPred

0.52

Loss of phosphorylation at Y181 (P = 0.0484);.;

MVP

0.91

MPC

0.11

ClinPred

0.70

GERP RS

2.8

Varity_R

0.49

gMVP

0.82

Mutation Taster

=47/53

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over