20-427400-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_031229.4(RBCK1):c.1117A>T(p.Thr373Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000105 in 1,614,024 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. T373T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000089 (0 hom.)
• Consequence: RBCK1 NM_031229.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.78

Genes affected

RBCK1 (HGNC:15864): (RANBP2-type and C3HC4-type zinc finger containing 1) Enables several functions, including identical protein binding activity; protein sequestering activity; and ubiquitin binding activity. Involved in several processes, including T cell receptor signaling pathway; cellular protein metabolic process; and regulation of DNA-binding transcription factor activity. Part of LUBAC complex. Implicated in glycogen storage disease. [provided by Alliance of Genome Resources, Apr 2022]

TBC1D20 (HGNC:16133): (TBC1 domain family member 20) This gene encodes a protein that belongs to a family of GTPase activator proteins of Rab-like small GTPases. The encoded protein and its cognate GTPase, Rab1, bind the nonstructural protein 5A (NS5A) of the hepatitis C virus (HCV) to mediate viral replication. Depletion of this protein inhibits replication of the virus and HCV infection. Mutations in this gene are associated with Warburg micro syndrome 4. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RBCK1	NM_031229.4	c.1117A>T	p.Thr373Ser	missense_variant	9/12	ENST00000356286.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RBCK1	ENST00000356286.10	c.1117A>T	p.Thr373Ser	missense_variant	9/12	1	NM_031229.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152032 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000770

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000278 AC: 7 AN: 251458 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135918

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000326

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000889 AC: 13 AN: 1461874 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727236

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000327

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 AF: 0.0000263 AC: 4 AN: 152150 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74388

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000772

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000340

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Polyglucosan body myopathy type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 28, 2018

This sequence change replaces threonine with serine at codon 373 of the RBCK1 protein (p.Thr373Ser). The threonine residue is highly conserved and there is a small physicochemical difference between threonine and serine. This variant is present in population databases (rs531364402, ExAC 0.03%). This variant has not been reported in the literature in individuals with RBCK1-related conditions. 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, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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	Benign	0.19
BayesDel_addAF	Benign	-0.090	T
BayesDel_noAF	Uncertain	-0.070
Cadd	Uncertain	24
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.72	D;.;.;.
Eigen	Pathogenic	0.76
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.87	D;D;D;.
M_CAP	Uncertain	0.13	D
MetaRNN	Uncertain	0.60	D;D;D;D
MetaSVM	Uncertain	0.37	D
MutationAssessor	Uncertain	2.5	M;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-3.7	D;.;D;D
REVEL	Uncertain	0.64
Sift	Uncertain	0.018	D;.;D;T
Sift4G	Uncertain	0.012	D;.;D;D
Polyphen		1.0	D;D;D;D
Vest4		0.34
MutPred		0.44		Gain of loop (P = 0.0435);.;.;.;
MVP		0.85
MPC		1.2
ClinPred		0.92	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.48
gMVP		0.76

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: rs531364402; hg19: chr20-408044;