20-10405271-T-C

Variant names:

• chr20-10405271-T-C
• rs147688404
• NM_170784.3:c.1689A>G

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 2P and 7B. PM2 BP4_Strong BP6_Moderate BP7

The NM_170784.3(MKKS):​c.1689A>G​(p.Ser563Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,612,866 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 benign (★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: MKKS NM_170784.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:2
• Conservation: PhyloP100: -1.49

Genes affected

MKKS (HGNC:7108): (MKKS centrosomal shuttling protein) This gene encodes a protein which shares sequence similarity with other members of the type II chaperonin family. The encoded protein is a centrosome-shuttling protein and plays an important role in cytokinesis. This protein also interacts with other type II chaperonin members to form a complex known as the BBSome, which involves ciliary membrane biogenesis. This protein is encoded by a downstream open reading frame (dORF). Several upstream open reading frames (uORFs) have been identified, which repress the translation of the dORF, and two of which can encode small mitochondrial membrane proteins. Mutations in this gene have been observed in patients with Bardet-Biedl syndrome type 6, also known as McKusick-Kaufman syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2023]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.67).
• BP6: Variant 20-10405271-T-C is Benign according to our data. Variant chr20-10405271-T-C is described in ClinVar as [Likely_benign]. Clinvar id is 1896889.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr20-10405271-T-C is described in Lovd as [Likely_benign].
• BP7: Synonymous conserved (PhyloP=-1.49 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MKKS	NM_170784.3	c.1689A>G	p.Ser563Ser	synonymous_variant	Exon 6 of 6	ENST00000347364.7	NP_740754.1
MKKS	NM_018848.3	c.1689A>G	p.Ser563Ser	synonymous_variant	Exon 6 of 6		NP_061336.1
MKKS	NR_072977.2	n.1050A>G		non_coding_transcript_exon_variant	Exon 5 of 5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MKKS	ENST00000347364.7	c.1689A>G	p.Ser563Ser	synonymous_variant	Exon 6 of 6	1	NM_170784.3	ENSP00000246062.4
MKKS	ENST00000399054.6	c.1689A>G	p.Ser563Ser	synonymous_variant	Exon 6 of 6	1		ENSP00000382008.2
MKKS	ENST00000651692.1	c.1689A>G	p.Ser563Ser	synonymous_variant	Exon 7 of 7			ENSP00000498849.1
MKKS	ENST00000652676.1	n.1333A>G		non_coding_transcript_exon_variant	Exon 7 of 7

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152202 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249798 Hom.: 0 AF XY: 0.00000740 AC XY: 1 AN XY: 135106

Gnomad AFR exome AF: 0.0000619

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1460664 Hom.: 0 Cov.: 30 AF XY: 0.00000551 AC XY: 4 AN XY: 726602

Gnomad4 AFR exome AF: 0.000120

Gnomad4 AMR exome AF: 0.0000449

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152202 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74358

Gnomad4 AFR AF: 0.0000724

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000264

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, single submitter

Submissions by phenotype

MKKS-related disorder Benign:1

Sep 30, 2022

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Bardet-Biedl syndrome;C0948368:McKusick-Kaufman syndrome Benign:1

May 21, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.67
CADD	Benign	4.5
DANN	Benign	0.64

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

Publications

LitVar

Other links and lift over

dbSNP: rs147688404; hg19: chr20-10385919;