X-55001614-C-T

Position:

• chrX-55001614-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PP3_Strong BS2

The NM_001271748.2(APEX2):​c.-107C>T variant causes a 5 prime UTR premature start codon gain change. The variant allele was found at a frequency of 0.00000275 in 1,090,158 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 2 hemizygotes in GnomAD. 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)
  • Exomes 𝑓: 0.0000028 (0 hom. 2 hem.)
• Consequence: APEX2 NM_001271748.2 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.90

Genes affected

APEX2 (HGNC:17889): (apurinic/apyrimidinic endodeoxyribonuclease 2) Apurinic/apyrimidinic (AP) sites occur frequently in DNA molecules by spontaneous hydrolysis, by DNA damaging agents or by DNA glycosylases that remove specific abnormal bases. AP sites are pre-mutagenic lesions that can prevent normal DNA replication so the cell contains systems to identify and repair such sites. Class II AP endonucleases cleave the phosphodiester backbone 5' to the AP site. This gene encodes a protein shown to have a weak class II AP endonuclease activity. Most of the encoded protein is located in the nucleus but some is also present in mitochondria. This protein may play an important role in both nuclear and mitochondrial base excision repair. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Nov 2012]

APEX2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.954
• BS2: High Hemizygotes in GnomAdExome4 at 2 gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APEX2	NM_014481.4	c.226C>T	p.Arg76Cys	missense_variant	2/6	ENST00000374987.4	NP_055296.2
APEX2	NM_001271748.2	c.-107C>T		5_prime_UTR_premature_start_codon_gain_variant	2/5		NP_001258677.1
APEX2	NM_001271748.2	c.-107C>T		5_prime_UTR_variant	2/5		NP_001258677.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APEX2	ENST00000374987.4	c.226C>T	p.Arg76Cys	missense_variant	2/6	1	NM_014481.4	ENSP00000364126.3
APEX2	ENST00000471758.1	n.256C>T		non_coding_transcript_exon_variant	2/5	2

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000275 AC: 3 AN: 1090158 Hom.: 0 Cov.: 29 AF XY: 0.00000561 AC XY: 2 AN XY: 356196

Gnomad4 AFR exome AF: 0.00

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: 0.00000358

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

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

Jul 30, 2024

The c.226C>T (p.R76C) alteration is located in exon 2 (coding exon 2) of the APEX2 gene. This alteration results from a C to T substitution at nucleotide position 226, causing the arginine (R) at amino acid position 76 to be replaced by a cysteine (C). 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
AlphaMissense	Benign	0.11
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	26
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.73	D
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.55	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Uncertain	0.24	D
MutationAssessor	Pathogenic	3.8	H
PrimateAI	Uncertain	0.58	T
PROVEAN	Pathogenic	-6.1	D
REVEL	Uncertain	0.57
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.71
MutPred		0.78		Loss of disorder (P = 0.0138);
MVP		0.70
MPC		0.75
ClinPred		1.0	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.71
gMVP		0.82

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: rs1301444460; hg19: chrX-55028047; COSMIC: COSV100895151; COSMIC: COSV100895151;