22-38736299-G-A

Variant names:

• chr22-38736299-G-A
• NM_015374.3:c.2122C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_015374.3(SUN2):​c.2122C>T​(p.Arg708Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000342 in 1,461,644 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: SUN2 NM_015374.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.86
• Publications: 0 publications found

Genes affected

SUN2 (HGNC:14210): (Sad1 and UNC84 domain containing 2) SUN1 (MIM 607723) and SUN2 are inner nuclear membrane (INM) proteins that play a major role in nuclear-cytoplasmic connection by formation of a 'bridge' across the nuclear envelope, known as the LINC complex, via interaction with the conserved luminal KASH domain of nesprins (e.g., SYNE1; MIM 608441) located in the outer nuclear membrane (ONM). The LINC complex provides a direct connection between the nuclear lamina and the cytoskeleton, which contributes to nuclear positioning and cellular rigidity (summary by Haque et al., 2010 [PubMed 19933576]).[supplied by OMIM, Nov 2010]

GTPBP1 (HGNC:4669): (GTP binding protein 1) This gene is upregulated by interferon-gamma and encodes a protein that is a member of the AGP11/GTPBP1 family of GTP-binding proteins. A structurally similar protein has been found in mouse, where disruption of the gene for that protein had no observable phenotype. [provided by RefSeq, Jul 2008]

GTPBP1 Gene-Disease associations (from GenCC):

• neurodevelopmental disorder with characteristic facial and ectodermal features and tetraparesis 1

  Inheritance: AR Classification: MODERATE Submitted by: G2P

ENSG00000230149 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.948

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SUN2	NM_015374.3	c.2122C>T	p.Arg708Cys	missense_variant	Exon 18 of 18	ENST00000689035.1	NP_056189.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SUN2	ENST00000689035.1	c.2122C>T	p.Arg708Cys	missense_variant	Exon 18 of 18		NM_015374.3	ENSP00000508608.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461644 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727134

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44692

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111876

Other (OTH) AF: 0.00 AC: 0 AN: 60378

GnomAD4 genome Cov.: 33

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Emery-Dreifuss muscular dystrophy Uncertain:1

May 13, 2022

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. 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 disruptive. This variant has not been reported in the literature in individuals affected with SUN2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 708 of the SUN2 protein (p.Arg708Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	34
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.63	D;.;D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	.;D;D
M_CAP	Uncertain	0.093	D
MetaRNN	Pathogenic	0.95	D;D;D
MetaSVM	Uncertain	0.15	D
MutationAssessor	Pathogenic	3.4	M;.;M
PhyloP100		6.9
PrimateAI	Pathogenic	0.80	D
PROVEAN	Pathogenic	-7.6	D;D;D
REVEL	Pathogenic	0.66
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.89
MutPred		0.82		Loss of methylation at R708 (P = 0.0257);.;Loss of methylation at R708 (P = 0.0257);
MVP		0.84
MPC		1.0
ClinPred		1.0	D
GERP RS		4.3
Varity_R		0.97
gMVP		0.84
Mutation Taster		=26/74	disease causing

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

hg19: chr22-39132304; COSMIC: COSV53283953; COSMIC: COSV53283953;