15-25356713-C-G

Variant names:

• chr15-25356713-C-G
• rs374601913
• NM_130839.5:c.1937G>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_130839.5(UBE3A):​c.1937G>C​(p.Arg646Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,972 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts 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. R646C) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: UBE3A NM_130839.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.81
• Publications: 2 publications found

Genes affected

UBE3A (HGNC:12496): (ubiquitin protein ligase E3A) This gene encodes an E3 ubiquitin-protein ligase, part of the ubiquitin protein degradation system. This imprinted gene is maternally expressed in brain and biallelically expressed in other tissues. Maternally inherited deletion of this gene causes Angelman Syndrome, characterized by severe motor and intellectual retardation, ataxia, hypotonia, epilepsy, absence of speech, and characteristic facies. The protein also interacts with the E6 protein of human papillomavirus types 16 and 18, resulting in ubiquitination and proteolysis of tumor protein p53. Alternative splicing of this gene results in three transcript variants encoding three isoforms with different N-termini. Additional transcript variants have been described, but their full length nature has not been determined. [provided by RefSeq, Jul 2008]

SNHG14 (HGNC:37462): (small nucleolar RNA host gene 14) This gene is located within the Prader-Willi critical region and produces a long, spliced paternally-imprinted RNA that initiates within a common upstream promoter region shared by the SNRPN (small nuclear ribonucleoprotein polypeptide N) and SNURF genes. This transcript serves as a host RNA for the small nucleolar RNA, C/D box 115 and 116 clusters. This RNA extends in antisense into the region of the ubiquitin protein ligase E3A gene (UBE3A), and is thought to regulate imprinted expression of UBE3A in the brain. This transcript undergoes extensive alternative splicing, and may initiate and terminate at multiple locations within this genomic region. The full-length structure of all splice forms is not determined. [provided by RefSeq, Mar 2017]

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the UBE3A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 44 curated pathogenic missense variants (we use a threshold of 10). The gene has 8 curated benign missense variants. Trascript score misZ: 6.9443 (above the threshold of 3.09). GenCC associations: The gene is linked to Angelman syndrome.
• BP4: Computational evidence support a benign effect (MetaRNN=0.4008542).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_130839.5. 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
	UBE3A	NM_130839.5	MANE Select	c.1937G>C	p.Arg646Pro	missense	Exon 8 of 13	NP_570854.1
	UBE3A	NM_000462.5		c.1946G>C	p.Arg649Pro	missense	Exon 9 of 14	NP_000453.2
	UBE3A	NM_001354505.1		c.1937G>C	p.Arg646Pro	missense	Exon 8 of 13	NP_001341434.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	UBE3A	ENST00000648336.2	MANE Select	c.1937G>C	p.Arg646Pro	missense	Exon 8 of 13	ENSP00000497572.2
	UBE3A	ENST00000566215.5	TSL:1	c.1877G>C	p.Arg626Pro	missense	Exon 10 of 15	ENSP00000457771.1
	SNHG14	ENST00000424333.6	TSL:1	n.5767-62075C>G		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460972 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726832

African (AFR) AF: 0.00 AC: 0 AN: 33448

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.00 AC: 0 AN: 39602

South Asian (SAS) AF: 0.00 AC: 0 AN: 86214

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5308

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111842

Other (OTH) AF: 0.00 AC: 0 AN: 60310

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Oct 16, 2015

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Angelman syndrome Uncertain:1

May 20, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Experimental studies have shown that this missense change does not substantially affect UBE3A function (PMID: 33607653). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on UBE3A protein function. ClinVar contains an entry for this variant (Variation ID: 437193). This variant has not been reported in the literature in individuals affected with UBE3A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 626 of the UBE3A protein (p.Arg626Pro).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.39
BayesDel_addAF	Uncertain	0.067	T
BayesDel_noAF	Benign	-0.14
CADD	Uncertain	24
DANN	Uncertain	0.98
DEOGEN2	Benign	0.11	T
Eigen	Benign	-0.029
Eigen_PC	Benign	0.13
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.88	D
M_CAP	Benign	0.023	T
MetaRNN	Benign	0.40	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.6	L
PhyloP100		2.8
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-1.3	N
REVEL	Benign	0.17
Sift	Benign	0.37	T
Sift4G	Benign	0.36	T
Polyphen		0.71	P
Vest4		0.59
MutPred		0.45		Loss of MoRF binding (P = 0.0465)
MVP		0.46
MPC		1.3
ClinPred		0.77	D
GERP RS		4.8
PromoterAI		-0.019	Neutral
Varity_R		0.85
gMVP		0.94

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

Other links and lift over

dbSNP: rs374601913; hg19: chr15-25601860;