chr17-58216088-C-T

Variant names:

• chr17-58216088-C-T
• rs386834048
• ENST00000537529.7:c.-13G>A

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PP3_Strong PP5

The ENST00000537529.7(MKS1):​c.-13G>A variant causes a splice region change. The variant allele was found at a frequency of 0.000152 in 1,614,030 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00012 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00015 (0 hom.)
• Consequence: MKS1 ENST00000537529.7 splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:18 U:1
• Conservation: PhyloP100: 6.25
• Publications: 7 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: Uncertain_significance. The variant received 5 ACMG points.

• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• PP5: Variant 17-58216088-C-T is Pathogenic according to our data. Variant chr17-58216088-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1392.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MKS1	NM_017777.4	c.417G>A	p.Glu139Glu	splice_region_variant, synonymous_variant	Exon 4 of 18	ENST00000393119.7	NP_060247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MKS1	ENST00000393119.7	c.417G>A	p.Glu139Glu	splice_region_variant, synonymous_variant	Exon 4 of 18	1	NM_017777.4	ENSP00000376827.2

Frequencies

GnomAD3 genomes AF: 0.000125 AC: 19 AN: 152186 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00115

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000206

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.000128 AC: 32 AN: 249574 AF XY: 0.000148

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000579

Gnomad ASJ exome AF: 0.000298

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000238

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000155 AC: 226 AN: 1461844 Hom.: 0 Cov.: 30 AF XY: 0.000151 AC XY: 110 AN XY: 727222

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

American (AMR) AF: 0.0000894 AC: 4 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.000650 AC: 17 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

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

European-Non Finnish (NFE) AF: 0.000176 AC: 196 AN: 1111988

Other (OTH) AF: 0.000149 AC: 9 AN: 60396

GnomAD4 genome AF: 0.000125 AC: 19 AN: 152186 Hom.: 0 Cov.: 32 AF XY: 0.0000941 AC XY: 7 AN XY: 74354

African (AFR) AF: 0.0000241 AC: 1 AN: 41434

American (AMR) AF: 0.00 AC: 0 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00115 AC: 4 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000206 AC: 14 AN: 68034

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.000173 Hom.: 0

Bravo AF: 0.0000945

EpiCase AF: 0.00

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:18 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:6 Uncertain:1

Mar 14, 2016

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Clinical Genetics, Academic Medical Center

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 20, 2022

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Meckel syndrome, type 1 Pathogenic:4

Oct 11, 2018

Illumina Laboratory Services, Illumina

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MKS1 c.417G>A (p.Glu139Glu) variant has been reported in three studies in probands with Meckel syndrome (MKS) in which it is found in a total of four individuals, all in a compound heterozygous state with a second pathogenic variant (Consugar et al. 2007; Khaddour et al. 2007; Frank et al. 2007). The p.Glu139Glu variant was absent from 410 control chromosomes but is reported at a frequency of 0.000394 in the Ashkenazi Jewish population of the Genome Aggregation Database. The p.Glu139Glu variant is a synonymous variant that affects the last nucleotide of exon four and is predicted to destroy the splice donor site. RT-PCR and sequence analysis of proband fibroblasts showed a smaller abnormal band which when sequenced, confirmed that the variant results in skipping of exon 4 (Consugar et al. 2007). Aberrant splicing is a known mechanism in MKS. Based on the evidence, the p.Glu139Glu variant is classified as likely pathogenic for Meckel syndrome. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

May 01, 2023

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MKS1 c.417G>A (p.Glu139Glu) alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Two predict the variant abolishes the canonical 5' splicing donor site. At least one publication reports experimental evidence that this variant indeed affects mRNA splicing, leading to the skipping of exon 4 which results in an in-frame deletion (p.Phe88_Glu139del) (Consugar_2007). The variant allele was found at a frequency of 0.00013 in 249574 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in MKS1 causing Meckel Syndrome Type 1 (0.00013 vs 0.0011), allowing no conclusion about variant significance. c.417G>A has been reported in the literature as a biallelic genotype in multiple individuals affected with Meckel Syndrome Type 1, including one homozygote and at least three cases where it was found in trans with a pathogenic variant (e.g. Frank_2007, Consugar_2007, Khaddour_2007, Meier_2019). The variant has also been reported in at least one individual affected with Joubert syndrome (e.g. Bachmann-Gagescu_2015). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 26092869, 17377820, 17437276, 17397051, 30679815, 26490104, 28497568, 19466712). Eight submitters have provided clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as either pathogenic (n=2)/likely pathogenic (n=4) or VUS (n=2). Based on the evidence outlined above, the variant was classified as pathogenic. -

-

Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Jun 01, 2007

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Bardet-Biedl syndrome 13;C3714506:Meckel syndrome, type 1;C4310705:Joubert syndrome 28 Pathogenic:2

Apr 24, 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. -

May 19, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases Pathogenic:1

Oct 09, 2021

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.417G>A (p.E139E) alteration is located in coding exon 4 of the MKS1 gene. This alteration consists of a G to A substitution at nucleotide position 417. This nucleotide substitution does not change the glutamic acid at codon 139. However, this change occurs in the last base pair of coding exon 4, which makes it likely to have some effect on normal mRNA splicing. This variant has been identified in individuals with Meckel syndrome as well as Joubert syndrome in conjunction with a second MKS1 variant (Frank, 2007; Khaddour, 2007; Consugar, 2007; Bachmann-Gagescu, 2015; Summers, 2017). RT-PCR of fibroblasts from an individual with Meckel syndrome and this variant demonstrated exon skipping (Consugar, 2007). In silico splice site analysis predicts that this alteration may weaken the native splice donor site. Based on the available evidence, this alteration is classified as likely pathogenic. -

Bardet-Biedl syndrome 13 Pathogenic:1

Mar 23, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Joubert syndrome Pathogenic:1

Feb 23, 2015

UW Hindbrain Malformation Research Program, University of Washington

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Meckel-Gruber syndrome Pathogenic:1

Jul 31, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Glu139Glu (NM_017777.3 c.417G>A) variant in MKS1 has been reported in 8 co mpound heterozygous individuals with Meckel syndrome and 1 compound heterozygous individual with Joubert syndrome (Consugar 2007, Khaddour 2007, Frank 2007, Tal lila 2009, Bachmann-Gagescu 2015). This variant is located in the last base of t he exon, which is part of the 5? splice region, and has been demonstrated to imp act splicing in patient cells (Consugar 2007). It has been identified in 31/126, 722 European chromosomes by the Genome Aggregation Database (gnomAD, http://gnom ad.broadinstitute.org; dbSNP rs386834048, rs370514840). Although this variant ha s been seen in the general population, its frequency is low enough to be consist ent with a recessive carrier frequency. Biallelic loss of function of the MKS1 g ene is associated with Meckel syndrome and Joubert syndrome. In summary, the p. Glu139Glu variant is likely pathogenic for Meckel syndrome in an autosomal reces sive manner based on its occurrence in affected individuals and demonstrated imp act on splicing. -

MKS1-related disorder Pathogenic:1

Apr 09, 2024

PreventionGenetics, part of Exact Sciences

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The MKS1 c.417G>A is a noncoding alteration. This variant is predicted to alter splicing based on available splicing prediction programs (SpliceAI, Jaganathan et al. 2019. PubMed ID: 30661751). This variant has been reported in individuals with Joubert syndrome (Table S5, Bachmann-Gagescu et al. 2015. PubMed ID: 26092869; Supplemental Table II, Summers et al. 2017. PubMed ID: 28497568) and Meckel syndrome (Consugar et al. 2007. PubMed ID: 17377820; Meier et al. 2019. PubMed ID: 30679815). mRNA studies in affected individual's fibroblasts confirmed that this variant results in the skipping of exon 4 (Consugar et al. 2007. PubMed ID: 17377820). This variant is reported in 0.039% of alleles in individuals of Ashkenazi Jewish descent in gnomAD. This variant is interpreted as likely pathogenic. -

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

Jan 21, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects codon 139 of the MKS1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MKS1 protein. RNA analysis indicates that this variant induces altered splicing and likely results in a shortened protein product. This variant is present in population databases (rs386834048, gnomAD 0.04%). This variant has been observed in individual(s) with Meckel syndrome or Joubert syndrome (PMID: 17377820, 17397051, 17437276, 26092869, 26490104, 28497568). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 1392). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in skipping of exon 4, but is expected to preserve the integrity of the reading-frame (PMID: 17377820). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.14
CADD	Benign	23
DANN	Benign	0.89
PhyloP100		6.2
Mutation Taster		=1/99	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.42		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.42		Position offset: 0

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

Other links and lift over

dbSNP: rs386834048; hg19: chr17-56293449;