14-80202894-G-A

Position:

• chr14-80202894-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_013989.5(DIO2):​c.617C>T​(p.Pro206Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,712 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: DIO2 NM_013989.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 10.0

Genes affected

DIO2 (HGNC:2884): (iodothyronine deiodinase 2) The protein encoded by this gene belongs to the iodothyronine deiodinase family. It catalyzes the conversion of prohormone thyroxine (3,5,3',5'-tetraiodothyronine, T4) to the bioactive thyroid hormone (3,5,3'-triiodothyronine, T3) by outer ring 5'-deiodination. This gene is widely expressed, including in thyroid and brain. It is thought to be responsible for the 'local' production of T3, and thus important in influencing thyroid hormone action in these tissues. It has also been reported to be highly expressed in thyroids of patients with Graves disease, and in follicular adenomas. The intrathyroidal T4 to T3 conversion by this enzyme may contribute significantly to the relative increase in thyroidal T3 production in these patients. This protein is a selenoprotein containing the non-standard amino acid, selenocysteine (Sec), which is encoded by the UGA codon that normally signals translation termination. The 3' UTRs of selenoprotein mRNAs contain a conserved stem-loop structure, designated the Sec insertion sequence (SECIS) element, that is necessary for the recognition of UGA as a Sec codon, rather than as a stop signal. Unlike the other two members (DIO1 and DIO3) of this enzyme family, the mRNA for this gene contains an additional in-frame UGA codon that has been reported (in human) to function either as a Sec or a stop codon, which can result in two isoforms with one or two Sec residues; however, only the upstream Sec (conserved with the single Sec residue found at the active site in DIO1 and DIO3) was shown to be essential for enzyme activity (PMID:10403186). Alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, Oct 2018]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.83

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DIO2	NM_013989.5	c.617C>T	p.Pro206Leu	missense_variant	2/2	ENST00000438257.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
DIO2	ENST00000438257.9	c.617C>T	p.Pro206Leu	missense_variant	2/2	1	NM_013989.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000802 AC: 2 AN: 249222 Hom.: 0 AF XY: 0.00000740 AC XY: 1 AN XY: 135198

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000111

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: 0.00000137 AC: 2 AN: 1461712 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727138

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ExAC AF: 0.00000826 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 17, 2023

The c.617C>T (p.P206L) alteration is located in exon 2 (coding exon 2) of the DIO2 gene. This alteration results from a C to T substitution at nucleotide position 617, causing the proline (P) at amino acid position 206 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.26
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.31	T;T;.
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Uncertain	0.90	D
MetaRNN	Pathogenic	0.83	D;D;D
MetaSVM	Uncertain	-0.24	T
MutationAssessor	Uncertain	2.9	M;M;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-6.1	D;D;D
REVEL	Uncertain	0.44
Sift	Uncertain	0.0010	D;D;D
Sift4G	Uncertain	0.0050	D;D;D
Polyphen		1.0	D;D;.
MutPred		0.66		Gain of catalytic residue at V211 (P = 0.0047);Gain of catalytic residue at V211 (P = 0.0047);.;
MVP		0.93
MPC		0.91
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.56

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: rs766634398; hg19: chr14-80669237; COSMIC: COSV70444816;