17-58207105-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_017777.4(MKS1):c.1387C>A(p.Arg463=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. R463R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MKS1 NM_017777.4 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.615

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MKS1	NM_017777.4	c.1387C>A	p.Arg463=	synonymous_variant	15/18	ENST00000393119.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MKS1	ENST00000393119.7	c.1387C>A	p.Arg463=	synonymous_variant	15/18	1	NM_017777.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Meckel-Gruber syndrome;C0431399:Familial aplasia of the vermis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 25, 2022

This sequence change affects codon 463 of the MKS1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MKS1 protein. 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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
BayesDel_noAF	Benign	-0.37
Cadd	Benign	18
Dann	Benign	0.78

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.68		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.68		Position offset: 4

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

Publications

LitVar

Other links and lift over

dbSNP: rs766392300; hg19: chr17-56284466;