chr20-63693248-G-T

Variant names:

• chr20-63693248-G-T
• rs146221660
• NM_001283009.2:c.2957G>T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001283009.2(RTEL1):​c.2957G>T​(p.Arg986Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,816 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R986Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: RTEL1 NM_001283009.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.682
• Publications: 2 publications found

Genes affected

RTEL1 (HGNC:15888): (regulator of telomere elongation helicase 1) This gene encodes a DNA helicase which functions in the stability, protection and elongation of telomeres and interacts with proteins in the shelterin complex known to protect telomeres during DNA replication. Mutations in this gene have been associated with dyskeratosis congenita and Hoyerall-Hreidarsson syndrome. Read-through transcription of this gene into the neighboring downstream gene, which encodes tumor necrosis factor receptor superfamily, member 6b, generates a non-coding transcript. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Sep 2013]

RTEL1-TNFRSF6B (HGNC:44095): (RTEL1-TNFRSF6B readthrough (NMD candidate)) This locus represents naturally occurring read-through transcription between the neighboring RTEL1 (regulator of telomere elongation helicase 1) and TNFRSF6B (tumor necrosis factor receptor superfamily, member 6b, decoy) genes on chromosome 20. The read-through transcript is a candidate for nonsense-mediated mRNA decay (NMD), and is unlikely to produce a protein product. [provided by RefSeq, Feb 2011]

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.056223452).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001283009.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	RTEL1	NM_001283009.2	MANE Select	c.2957G>T	p.Arg986Leu	missense	Exon 30 of 35	NP_001269938.1
	RTEL1	NM_032957.5		c.3029G>T	p.Arg1010Leu	missense	Exon 30 of 35	NP_116575.3
	RTEL1	NM_016434.4		c.2957G>T	p.Arg986Leu	missense	Exon 30 of 35	NP_057518.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	RTEL1	ENST00000360203.11	TSL:5 MANE Select	c.2957G>T	p.Arg986Leu	missense	Exon 30 of 35	ENSP00000353332.5
	RTEL1	ENST00000508582.7	TSL:2	c.3029G>T	p.Arg1010Leu	missense	Exon 30 of 35	ENSP00000424307.2
	RTEL1	ENST00000370018.7	TSL:1	c.2957G>T	p.Arg986Leu	missense	Exon 30 of 35	ENSP00000359035.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000402 AC: 1 AN: 248534 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459816 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726214

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44676

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26096

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52044

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111482

Other (OTH) AF: 0.00 AC: 0 AN: 60326

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000830 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Dyskeratosis congenita, autosomal recessive 5;C4225346:Pulmonary fibrosis and/or bone marrow failure, Telomere-related, 3 Uncertain:1

Oct 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 986 of the RTEL1 protein (p.Arg986Leu). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with RTEL1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The leucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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 v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.094
BayesDel_addAF	Benign	-0.41	T
BayesDel_noAF	Benign	-0.65
CADD	Benign	0.045
DANN	Benign	0.87
DEOGEN2	Benign	0.23	T
Eigen	Benign	-1.6
Eigen_PC	Benign	-1.8
FATHMM_MKL	Benign	0.093	N
LIST_S2	Benign	0.56	T
M_CAP	Benign	0.0077	T
MetaRNN	Benign	0.056	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.2	L
PhyloP100		-0.68
PrimateAI	Benign	0.18	T
PROVEAN	Uncertain	-2.5	N
REVEL	Benign	0.018
Sift	Benign	0.12	T
Sift4G	Benign	0.28	T
Polyphen		0.0060	B
Vest4		0.15
MutPred		0.48		Loss of MoRF binding (P = 0.0534)
MVP		0.20
ClinPred		0.054	T
GERP RS		-9.6
Varity_R		0.061
gMVP		0.31
Mutation Taster		=97/3	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.11		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: rs146221660; hg19: chr20-62324601;