X-71136591-C-T

Position:

• chrX-71136591-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The ENST00000374080.8(MED12):​c.5336C>T​(p.Thr1779Ile) variant causes a missense change involving the alteration of a 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 (★).

• Frequency: Genomes: not found (cov: 21)
• Consequence: MED12 ENST00000374080.8 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.52

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]

MED12 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MED12. . Gene score misZ 6.5797 (greater than the threshold 3.09). GenCC has associacion of gene with 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=0.18452129).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MED12	NM_005120.3	c.5336C>T	p.Thr1779Ile	missense_variant	37/45	ENST00000374080.8	NP_005111.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MED12	ENST00000374080.8	c.5336C>T	p.Thr1779Ile	missense_variant	37/45	1	NM_005120.3	ENSP00000363193.3

Frequencies

GnomAD3 genomes Cov.: 21

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 21

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

Labcorp Genetics (formerly Invitae), Labcorp

Sep 13, 2017

This sequence change replaces threonine with isoleucine at codon 1779 of the MED12 protein (p.Thr1779Ile). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and isoleucine. 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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C15"). This variant has not been reported in the literature in individuals with MED12-related disease. This variant is not present in population databases (ExAC no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.44
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.099	T;.;D
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.86	D;D;D
M_CAP	Benign	0.051	D
MetaRNN	Benign	0.18	T;T;T
MetaSVM	Benign	-0.87	T
MutationAssessor	Benign	1.2	.;L;L
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-2.2	.;N;N
REVEL	Benign	0.098
Sift	Benign	0.037	.;D;D
Sift4G	Uncertain	0.017	D;D;T
Polyphen		0.42	B;B;B
Vest4		0.21
MutPred		0.26		.;Loss of phosphorylation at T1779 (P = 4e-04);Loss of phosphorylation at T1779 (P = 4e-04);
MVP		0.43
MPC		0.94
ClinPred		0.81	D
GERP RS		4.2
Varity_R		0.17
gMVP		0.18

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: rs1556338856; hg19: chrX-70356441;