X-71118853-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_005120.3(MED12):c.99G>A(p.Glu33=) variant causes a splice region, synonymous change. The variant allele was found at a frequency of 0.00000274 in 1,094,709 control chromosomes in the GnomAD database, with no homozygous occurrence. There are no hemizygote samples in GnomAD. 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 20)
  • Exomes 𝑓: 0.0000027 (0 hom. 0 hem.)
• Consequence: MED12 NM_005120.3 splice_region, synonymous
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.14

Genes affected

MED12 (HGNC:11957): (mediator complex subunit 12) The initiation of transcription is controlled in part by a large protein assembly known as the preinitiation complex. A component of this preinitiation complex is a 1.2 MDa protein aggregate called Mediator. This Mediator component binds with a CDK8 subcomplex which contains the protein encoded by this gene, mediator complex subunit 12 (MED12), along with MED13, CDK8 kinase, and cyclin C. The CDK8 subcomplex modulates Mediator-polymerase II interactions and thereby regulates transcription initiation and reinitation rates. The MED12 protein is essential for activating CDK8 kinase. Defects in this gene cause X-linked Opitz-Kaveggia syndrome, also known as FG syndrome, and Lujan-Fryns syndrome. [provided by RefSeq, Aug 2009]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MED12	NM_005120.3	c.99G>A	p.Glu33=	splice_region_variant, synonymous_variant	1/45	ENST00000374080.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MED12	ENST00000374080.8	c.99G>A	p.Glu33=	splice_region_variant, synonymous_variant	1/45	1	NM_005120.3	P4

Frequencies

GnomAD3 genomes Cov.: 20

GnomAD4 exome AF: 0.00000274 AC: 3 AN: 1094709 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 360247

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000745

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 20

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

FG syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 15, 2023

This sequence change affects codon 33 of the MED12 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MED12 protein. This variant also falls at the last nucleotide of exon 1, which is part of the consensus splice site for this exon. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MED12-related conditions. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus 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	-0.22
Cadd	Uncertain	25
Dann	Benign	0.97
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.23		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.23		Position offset: 43

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-70338703;