rs771349148

Variant names:

• chrX-71132107-C-T
• rs771349148
• NM_005120.3:c.4154C>T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_005120.3(MED12):​c.4154C>T​(p.Ala1385Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,096,640 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 1 hemizygotes in GnomAD. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000027 (0 hom. 1 hem.)
• Consequence: MED12 NM_005120.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.97

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the MED12 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 37 curated pathogenic missense variants (we use a threshold of 10). The gene has 108 curated benign missense variants. Gene score misZ: 6.5797 (above the threshold of 3.09). GenCC associations: The gene is linked to MED12-related intellectual disability syndrome, X-linked intellectual disability with marfanoid habitus, blepharophimosis - intellectual disability syndrome, MKB type, FG syndrome 1, cholestasis-pigmentary retinopathy-cleft palate syndrome.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MED12	NM_005120.3	c.4154C>T	p.Ala1385Val	missense_variant	Exon 30 of 45	ENST00000374080.8	NP_005111.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MED12	ENST00000374080.8	c.4154C>T	p.Ala1385Val	missense_variant	Exon 30 of 45	1	NM_005120.3	ENSP00000363193.3

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD3 exomes AF: 0.0000110 AC: 2 AN: 181723 Hom.: 0 AF XY: 0.0000148 AC XY: 1 AN XY: 67549

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000731

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: 0.00000274 AC: 3 AN: 1096640 Hom.: 0 Cov.: 31 AF XY: 0.00000276 AC XY: 1 AN XY: 362030

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000568

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: 0.00

Gnomad4 OTH exome AF: 0.0000217

GnomAD4 genome Cov.: 23

Bravo AF: 0.00000378

ExAC AF: 0.00000826 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

May 05, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A1385V variant (also known as c.4154C>T), located in coding exon 30 of the MED12 gene, results from a C to T substitution at nucleotide position 4154. The alanine at codon 1385 is replaced by valine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

FG syndrome Uncertain:1

Jan 18, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1385 of the MED12 protein (p.Ala1385Val). This variant is present in population databases (rs771349148, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with MED12-related conditions. ClinVar contains an entry for this variant (Variation ID: 528482). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MED12 protein function. 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
AlphaMissense	Uncertain	0.56
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.32
CADD	Uncertain	26
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.11	T;.;D
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Benign	0.051	D
MetaRNN	Uncertain	0.60	D;D;D
MetaSVM	Benign	-0.63	T
MutationAssessor	Uncertain	2.3	.;M;M
PrimateAI	Uncertain	0.78	T
PROVEAN	Uncertain	-3.6	.;D;D
REVEL	Benign	0.22
Sift	Uncertain	0.0020	.;D;D
Sift4G	Uncertain	0.049	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.79
MutPred		0.26		.;Gain of methylation at K1384 (P = 0.0386);Gain of methylation at K1384 (P = 0.0386);
MVP		0.73
MPC		1.7
ClinPred		0.85	D
GERP RS		4.4
Varity_R		0.84
gMVP		0.72

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs771349148; hg19: chrX-70351957; COSMIC: COSV61357302; COSMIC: COSV61357302;