X-74524723-C-T

Variant names:

• chrX-74524723-C-T
• rs766773277
• NM_006517.5:c.940C>T

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PVS1 PM2 PP3_Moderate PP5_Very_Strong

The NM_006517.5(SLC16A2):​c.940C>T​(p.Arg314*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 23)
• Consequence: SLC16A2 NM_006517.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 0.487

Genes affected

SLC16A2 (HGNC:10923): (solute carrier family 16 member 2) This gene encodes an integral membrane protein that functions as a transporter of thyroid hormone. The encoded protein facilitates the cellular importation of thyroxine (T4), triiodothyronine (T3), reverse triiodothyronine (rT3) and diidothyronine (T2). This gene is expressed in many tissues and likely plays an important role in the development of the central nervous system. Loss of function mutations in this gene are associated with psychomotor retardation in males while females exhibit no neurological defects and more moderate thyroid-deficient phenotypes. This gene is subject to X-chromosome inactivation. Mutations in this gene are the cause of Allan-Herndon-Dudley syndrome. [provided by RefSeq, Mar 2012]

ACMG classification

Verdict is Pathogenic. Variant got 20 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant X-74524723-C-T is Pathogenic according to our data. Variant chrX-74524723-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 212186.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SLC16A2	NM_006517.5	c.940C>T	p.Arg314*	stop_gained	Exon 3 of 6	ENST00000587091.6	NP_006508.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SLC16A2	ENST00000587091.6	c.940C>T	p.Arg314*	stop_gained	Exon 3 of 6	1	NM_006517.5	ENSP00000465734.1
SLC16A2	ENST00000590447.1	c.379C>T	p.Arg127*	stop_gained	Exon 2 of 4	5		ENSP00000466213.1
SLC16A2	ENST00000636771.1	n.*641C>T		non_coding_transcript_exon_variant	Exon 4 of 7	5		ENSP00000490445.1
SLC16A2	ENST00000636771.1	n.*641C>T		3_prime_UTR_variant	Exon 4 of 7	5		ENSP00000490445.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Allan-Herndon-Dudley syndrome Pathogenic:2

Oct 02, 2021

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Stop-gained (nonsense): predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant (PVS1_VS). It is not observed in the gnomAD v2.1.1 dataset (PM2). The variant has been reported as pathogenic (ClinVar ID: VCV000212186.1). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

Jun 11, 2014

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Spastic paraplegia Pathogenic:1

Jan 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Arg314*) in the SLC16A2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SLC16A2 are known to be pathogenic (PMID: 20083155, 25527620). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with MCT8 deficiency (PMID: 32559475). This variant is also known as p.R388X. ClinVar contains an entry for this variant (Variation ID: 212186). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Jan 04, 2016

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The R314X variant in the SLC16A2 gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The R314X variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Protein truncating pathogenic variants downstream of this variant have been reported in the Human Gene Mutation Database in association with Allan-Herndon-Dudley syndrome (Stenson et al., 2014), supporting the pathogenicity of more upstream truncating variants. We interpret R314X as a pathogenic variant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	37
DANN	Uncertain	1.0
FATHMM_MKL	Uncertain	0.80	D
Vest4		0.91
GERP RS		2.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.92		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.92		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs766773277; hg19: chrX-73744558; COSMIC: COSV52086193;