NM_017777.4:c.763G>T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.

The NM_017777.4(MKS1):c.763G>T(p.Gly255Trp) variant causes a missense change. The variant allele was found at a frequency of 0.0000421 in 1,614,184 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. G255R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000044 ( 0 hom. )

Consequence

MKS1
NM_017777.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 3.97

Publications

5 publications found

Variant links:

Genes affected

MKS1 (HGNC:7121): (MKS transition zone complex subunit 1) The protein encoded by this gene localizes to the basal body and is required for formation of the primary cilium in ciliated epithelial cells. Mutations in this gene result in Meckel syndrome type 1 and in Bardet-Biedl syndrome type 13. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2009]

MKS1 Gene-Disease associations (from GenCC):

Meckel syndrome, type 1
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Myriad Women’s Health, Labcorp Genetics (formerly Invitae)
Bardet-Biedl syndrome 13
Inheritance: Unknown, AR Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P
Joubert syndrome 28
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
Bardet-Biedl syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Joubert syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Joubert syndrome with ocular defect
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Meckel syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

MKS1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MKS1	NM_017777.4 link	c.763G>T	p.Gly255Trp	missense_variant	Exon 8 of 18	ENST00000393119.7	NP_060247.2	Q9NXB0-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MKS1	ENST00000393119.7 link	c.763G>T	p.Gly255Trp	missense_variant	Exon 8 of 18	1	NM_017777.4	ENSP00000376827.2		Q9NXB0-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000104

AC:

AN:

249580

AF XY:

0.0000886

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000159

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000445

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.0000523

AC XY:

AN XY:

727238

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.000255

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000360

AC:

AN:

1111998

Other (OTH)

AF:

0.0000166

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.465

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

AF:

0.0000197

AC:

AN:

152308

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74480

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41548

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.000414

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.0000658

Hom.:

Bravo

AF:

0.0000453

ExAC

AF:

0.000199

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Meckel syndrome, type 1

Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Bardet-Biedl syndrome 13

Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Inborn genetic diseases

Uncertain:1

Dec 14, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.763G>T (p.G255W) alteration is located in exon 8 (coding exon 8) of the MKS1 gene. This alteration results from a G to T substitution at nucleotide position 763, causing the glycine (G) at amino acid position 255 to be replaced by a tryptophan (W). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Meckel-Gruber syndrome;C0431399:Joubert syndrome

Uncertain:1

Aug 30, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glycine with tryptophan at codon 255 of the MKS1 protein (p.Gly255Trp). The glycine residue is highly conserved and there is a large physicochemical difference between glycine and tryptophan. This variant is present in population databases (rs201237547, ExAC 0.04%). This variant has not been reported in the literature in individuals affected with MKS1-related conditions. ClinVar contains an entry for this variant (Variation ID: 324163). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). 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

Uncertain

0.44

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.19

CADD

Benign

(source)

DANN

Benign

0.93

DEOGEN2

Pathogenic

0.84

D;T;.

Eigen

Benign

0.066

Eigen_PC

Benign

0.085

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Benign

0.82

T;T;T

M_CAP

Uncertain

0.25

MetaRNN

Uncertain

0.43

T;T;T

MetaSVM

Benign

-0.35

MutationAssessor

Uncertain

2.5

M;.;.

PhyloP100

4.0

PrimateAI

Uncertain

0.60

PROVEAN

Uncertain

-3.6

D;.;D

REVEL

Uncertain

0.32

Sift

Benign

0.033

D;.;D

Sift4G

Pathogenic

0.0010

D;D;D

Polyphen

0.049

B;.;.

Vest4

0.48

MVP

0.74

MPC

0.34

ClinPred

0.20

GERP RS

4.9

Varity_R

0.17

gMVP

0.85

Mutation Taster

=69/31

polymorphism

(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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over