rs121912302

Positions:

• chrX-154765480-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP2 PP3_Moderate

The NM_001363.5(DKC1):​c.121G>A​(p.Glu41Lys) variant causes a missense change. 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: DKC1 NM_001363.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:2
• Conservation: PhyloP100: 7.18

Genes affected

DKC1 (HGNC:2890): (dyskerin pseudouridine synthase 1) This gene functions in two distinct complexes. It plays an active role in telomerase stabilization and maintenance, as well as recognition of snoRNAs containing H/ACA sequences which provides stability during biogenesis and assembly into H/ACA small nucleolar RNA ribonucleoproteins (snoRNPs). This gene is highly conserved and widely expressed, and may play additional roles in nucleo-cytoplasmic shuttling, DNA damage response, and cell adhesion. Mutations have been associated with X-linked dyskeratosis congenita. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_001363.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, DKC1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.896

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DKC1	NM_001363.5	c.121G>A	p.Glu41Lys	missense_variant	3/15	ENST00000369550.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
DKC1	ENST00000369550.10	c.121G>A	p.Glu41Lys	missense_variant	3/15	1	NM_001363.5	P2

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:2

Revision: criteria provided, single submitter

Submissions by phenotype

Dyskeratosis congenita, X-linked Other:2

not provided, no classification provided	literature only	GeneReviews	-	- -
not provided, no classification provided	literature only	UniProtKB/Swiss-Prot	-	- -

Dyskeratosis congenita Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 04, 2022

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 41 of the DKC1 protein (p.Glu41Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with dyskeratosis congenita (PMID: 10364516). ClinVar contains an entry for this variant (Variation ID: 38940). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. Experimental studies have shown that this missense change does not substantially affect DKC1 function (PMID: 22117216). 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 v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.42
BayesDel_addAF	Pathogenic	0.61	D
BayesDel_noAF	Pathogenic	0.64
CADD	Uncertain	25
DANN	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.90	D;D;D
MetaSVM	Uncertain	0.51	D
MutationAssessor	Uncertain	2.8	M;M;.
MutationTaster	Benign	1.0	A
PrimateAI	Uncertain	0.74	T
Sift4G	Uncertain	0.032	D;D;D
Polyphen		0.032	.;B;.
Vest4		0.76
MutPred		0.71		Gain of MoRF binding (P = 0.0355);Gain of MoRF binding (P = 0.0355);Gain of MoRF binding (P = 0.0355);
MVP		1.0
MPC		1.5
ClinPred		0.95	D
GERP RS		5.8
Varity_R		0.47
gMVP		0.87

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs121912302; hg19: chrX-153993755;