6-131607943-T-G

Variant names:

• chr6-131607943-T-G
• rs377352569
• NM_004830.4:c.1206A>C

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_004830.4(MED23):​c.1206A>C​(p.Leu402Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,518 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. L402L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MED23 NM_004830.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.653
• Publications: 0 publications found

Genes affected

MED23 (HGNC:2372): (mediator complex subunit 23) The activation of gene transcription is a multistep process that is triggered by factors that recognize transcriptional enhancer sites in DNA. These factors work with co-activators to direct transcriptional initiation by the RNA polymerase II apparatus. The protein encoded by this gene is a subunit of the CRSP (cofactor required for SP1 activation) complex, which, along with TFIID, is required for efficient activation by SP1. This protein is also a component of other multisubunit complexes e.g. thyroid hormone receptor-(TR-) associated proteins which interact with TR and facilitate TR function on DNA templates in conjunction with initiation factors and cofactors. This protein also acts as a metastasis suppressor. Several alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2012]

MED23 Gene-Disease associations (from GenCC):

• intellectual disability, autosomal recessive 18

  Inheritance: AR Classification: STRONG, MODERATE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• syndromic intellectual disability

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.71).
• BP7: Synonymous conserved (PhyloP=-0.653 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MED23	NM_004830.4	c.1206A>C	p.Leu402Leu	synonymous_variant	Exon 12 of 29	ENST00000368068.8	NP_004821.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MED23	ENST00000368068.8	c.1206A>C	p.Leu402Leu	synonymous_variant	Exon 12 of 29	1	NM_004830.4	ENSP00000357047.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461518 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727042

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33456

American (AMR) AF: 0.00 AC: 0 AN: 44704

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39640

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53362

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111854

Other (OTH) AF: 0.00 AC: 0 AN: 60364

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.71
CADD	Benign	4.8
DANN	Benign	0.69
PhyloP100		-0.65

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

Other links and lift over

dbSNP: rs377352569; hg19: chr6-131929083;