chrX-77682952-C-G

Position:

• chrX-77682952-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_000489.6(ATRX):​c.2304G>C​(p.Lys768Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000182 in 1,097,474 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 1 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 12/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000018 (0 hom. 1 hem.)
• Consequence: ATRX NM_000489.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.647

Genes affected

ATRX (HGNC:886): (ATRX chromatin remodeler) The protein encoded by this gene contains an ATPase/helicase domain, and thus it belongs to the SWI/SNF family of chromatin remodeling proteins. This protein is found to undergo cell cycle-dependent phosphorylation, which regulates its nuclear matrix and chromatin association, and suggests its involvement in the gene regulation at interphase and chromosomal segregation in mitosis. Mutations in this gene are associated with X-linked syndromes exhibiting cognitive disabilities as well as alpha-thalassemia (ATRX) syndrome. These mutations have been shown to cause diverse changes in the pattern of DNA methylation, which may provide a link between chromatin remodeling, DNA methylation, and gene expression in developmental processes. Multiple alternatively spliced transcript variants encoding distinct isoforms have been reported. [provided by RefSeq, Jul 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), ATRX. . Gene score misZ 3.1025 (greater than the threshold 3.09). GenCC has associacion of gene with alpha thalassemia-X-linked intellectual disability syndrome, ATR-X-related syndrome, intellectual disability-hypotonic facies syndrome, X-linked, 1.
• BP4: Computational evidence support a benign effect (MetaRNN=0.21425495).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ATRX	NM_000489.6	c.2304G>C	p.Lys768Asn	missense_variant	9/35	ENST00000373344.11	NP_000480.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ATRX	ENST00000373344.11	c.2304G>C	p.Lys768Asn	missense_variant	9/35	1	NM_000489.6	ENSP00000362441	P3

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000182 AC: 2 AN: 1097474 Hom.: 0 Cov.: 33 AF XY: 0.00000276 AC XY: 1 AN XY: 362902

Gnomad4 AFR exome AF: 0.0000758

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

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.: 23

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 25, 2017

- -

Alpha thalassemia-X-linked intellectual disability syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 09, 2021

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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0". The asparagine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with ATRX-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces lysine with asparagine at codon 768 of the ATRX protein (p.Lys768Asn). The lysine residue is moderately conserved and there is a moderate physicochemical difference between lysine and asparagine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.42
CADD	Benign	16
DANN	Benign	0.96
DEOGEN2	Benign	0.015	.;.;T;T
FATHMM_MKL	Benign	0.34	N
LIST_S2	Uncertain	0.90	D;.;D;D
M_CAP	Uncertain	0.26	D
MetaRNN	Benign	0.21	T;T;T;T
MetaSVM	Uncertain	0.092	D
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.45	T
PROVEAN	Benign	-0.87	N;N;.;.
REVEL	Uncertain	0.29
Sift	Uncertain	0.0010	D;D;.;.
Sift4G	Benign	0.41	T;T;T;.
Polyphen		0.75	P;.;.;.
Vest4		0.082
MutPred		0.16		Loss of ubiquitination at K768 (P = 0.0116);.;.;.;
MVP		0.84
MPC		0.083
ClinPred		0.57	D
GERP RS		1.1
gMVP		0.15

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: rs1557139920; hg19: chrX-76938444; COSMIC: COSV64874006; COSMIC: COSV64874006;