rs1555599412

Variant names:

• chr17-58213011-C-A
• rs1555599412
• NM_017777.4:c.829G>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_017777.4(MKS1):​c.829G>T​(p.Glu277*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. E277E) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MKS1 NM_017777.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 2.51
• Publications: 0 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-58213011-C-A is Pathogenic according to our data. Variant chr17-58213011-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 554581.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MKS1	NM_017777.4	c.829G>T	p.Glu277*	stop_gained	Exon 8 of 18	ENST00000393119.7	NP_060247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MKS1	ENST00000393119.7	c.829G>T	p.Glu277*	stop_gained	Exon 8 of 18	1	NM_017777.4	ENSP00000376827.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461882 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727240

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112006

Other (OTH) AF: 0.0000166 AC: 1 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000468 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Meckel syndrome, type 1 Pathogenic:1

Nov 17, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MKS1 c.829G>T (p.Glu277X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position are classified as pathogenic in ClinVar. The variant was absent in 249568 control chromosomes. To our knowledge, no occurrence of c.829G>T in individuals affected with Meckel Syndrome Type 1 and no experimental evidence demonstrating its impact on protein function have been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Both classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic.

Bardet-Biedl syndrome 13 Pathogenic:1

Oct 06, 2023

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Bardet-Biedl syndrome 13;C3714506:Meckel syndrome, type 1;C4310705:Joubert syndrome 28 Pathogenic:1

Oct 26, 2017

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.

not provided Pathogenic:1

Nov 03, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 25525159, 21228398)

Meckel-Gruber syndrome;C0431399:Joubert syndrome Pathogenic:1

Nov 20, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Glu277*) in the MKS1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MKS1 are known to be pathogenic (PMID: 19466712, 24886560, 26490104). This variant is not present in population databases (gnomAD no frequency). 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: 554581). For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	38
DANN	Uncertain	1.0
DEOGEN2	Benign	0.0	.;.;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.0	.;.;.;.
MetaRNN	Benign	0.0	.;.;.;.
MutationAssessor	Benign	0.0	.;.;.;.
PhyloP100		2.5
PROVEAN	Benign	0.0	.;.;.;.
REVEL	Benign	0.0
Sift	Pathogenic	0.0	.;.;.;.
Sift4G	Pathogenic	0.0	.;.;.;.
Vest4		0.73
ClinPred		1.0	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1555599412; hg19: chr17-56290372;