rs878854752

Variant names:

• chrX-71124988-A-G
• rs878854752
• NM_005120.3:c.2068A>G

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 1P and 7B. PP2 BP4_Moderate BS1_Supporting BS2

The NM_005120.3(MED12):​c.2068A>G​(p.Thr690Ala) variant causes a missense change. The variant allele was found at a frequency of 0.0000255 in 1,097,541 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 13 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 22)
  • Exomes 𝑓: 0.000026 (0 hom. 13 hem.)
• Consequence: MED12 NM_005120.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.95

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_benign. Variant got -6 ACMG points.

• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.089650124).
• BS1: Variant frequency is greater than expected in population nfe. gnomad4_exome allele frequency = 0.0000255 (28/1097541) while in subpopulation NFE AF= 0.0000321 (27/841488). AF 95% confidence interval is 0.000022. There are 0 homozygotes in gnomad4_exome. There are 13 alleles in male gnomad4_exome subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High Hemizygotes in GnomAdExome4 at 13 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MED12	NM_005120.3	c.2068A>G	p.Thr690Ala	missense_variant	Exon 15 of 45	ENST00000374080.8	NP_005111.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MED12	ENST00000374080.8	c.2068A>G	p.Thr690Ala	missense_variant	Exon 15 of 45	1	NM_005120.3	ENSP00000363193.3

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome AF: 0.0000255 AC: 28 AN: 1097541 Hom.: 0 Cov.: 33 AF XY: 0.0000358 AC XY: 13 AN XY: 362903

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: 0.0000185

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000321

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 22

Bravo AF: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

FG syndrome Uncertain:1

May 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 690 of the MED12 protein (p.Thr690Ala). 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. ClinVar contains an entry for this variant (Variation ID: 240095). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt MED12 protein function with a negative predictive value of 95%. 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	Benign	0.066
BayesDel_addAF	Benign	-0.36	T
BayesDel_noAF	Benign	-0.76
CADD	Benign	19
DANN	Benign	0.62
DEOGEN2	Benign	0.028	T;.;T
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.77	T;T;T
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.090	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-0.14	.;N;N
PrimateAI	Benign	0.41	T
PROVEAN	Benign	-0.53	.;N;N
REVEL	Benign	0.13
Sift	Benign	0.77	.;T;T
Sift4G	Benign	0.78	T;T;T
Polyphen		0.010	B;B;B
Vest4		0.13
MVP		0.73
MPC		0.90
ClinPred		0.49	T
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.13
gMVP		0.16

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs878854752; hg19: chrX-70344838;