20-427332-A-G

Variant summary

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

The NM_031229.4(RBCK1):c.1049A>G(p.Tyr350Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000372 in 1,614,030 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: RBCK1 NM_031229.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.57

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.1049A>G	p.Tyr350Cys	missense_variant	9/12	ENST00000356286.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RBCK1	ENST00000356286.10	c.1049A>G	p.Tyr350Cys	missense_variant	9/12	1	NM_031229.4	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152182 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: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251372 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135884

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461848 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727230

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152182 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74342

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000312 Hom.: 0

Bravo AF: 0.0000113

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

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

Apr 04, 2022

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 350 of the RBCK1 protein (p.Tyr350Cys). This variant is present in population databases (no rsID available, gnomAD 0.002%). This variant has not been reported in the literature in individuals affected with RBCK1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Not Available"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Not Available"). 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	0.31
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.10
Cadd	Pathogenic	29
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.67	D;.;.;.
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.90	D;D;D;.
M_CAP	Benign	0.036	D
MetaRNN	Uncertain	0.68	D;D;D;D
MetaSVM	Benign	-0.49	T
MutationAssessor	Uncertain	2.2	M;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.48	T
PROVEAN	Pathogenic	-7.2	D;.;D;D
REVEL	Uncertain	0.35
Sift	Uncertain	0.0030	D;.;D;D
Sift4G	Uncertain	0.0060	D;.;D;D
Polyphen		0.99	D;D;D;D
Vest4		0.68
MutPred		0.41		Loss of catalytic residue at L345 (P = 0.0597);.;.;.;
MVP		0.68
MPC		1.4
ClinPred		0.98	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.63
gMVP		0.89

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: rs1253008275; hg19: chr20-407976;