20-427309-G-A

Variant summary

Our verdict is Benign. Variant got -14 ACMG points: 2P and 16B. PM2 BP4_Strong BP6_Very_Strong BS1

The NM_031229.4(RBCK1):c.1030-4G>A variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000725 in 1,613,678 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00052 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000026 (0 hom.)
• Consequence: RBCK1 NM_031229.4 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.001926
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: 0.816

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 Benign. Variant got -14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.5).
• BP6: Variant 20-427309-G-A is Benign according to our data. Variant chr20-427309-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 788248.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000519 (79/152280) while in subpopulation AFR AF= 0.00173 (72/41546). AF 95% confidence interval is 0.00141. There are 0 homozygotes in gnomad4. There are 35 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RBCK1	NM_031229.4	c.1030-4G>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000356286.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RBCK1	ENST00000356286.10	c.1030-4G>A		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_031229.4	P1

Frequencies

GnomAD3 genomes AF: 0.000513 AC: 78 AN: 152162 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00171

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

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: 0.00

Gnomad OTH AF: 0.000956

GnomAD3 exomes AF: 0.0000956 AC: 24 AN: 250964 Hom.: 0 AF XY: 0.0000663 AC XY: 9 AN XY: 135656

Gnomad AFR exome AF: 0.00135

Gnomad AMR exome AF: 0.0000579

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000260 AC: 38 AN: 1461398 Hom.: 0 Cov.: 31 AF XY: 0.0000261 AC XY: 19 AN XY: 727000

Gnomad4 AFR exome AF: 0.000807

Gnomad4 AMR exome AF: 0.0000447

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: 0.00

Gnomad4 OTH exome AF: 0.000132

GnomAD4 genome AF: 0.000519 AC: 79 AN: 152280 Hom.: 0 Cov.: 32 AF XY: 0.000470 AC XY: 35 AN XY: 74474

Gnomad4 AFR AF: 0.00173

Gnomad4 AMR AF: 0.000327

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.000946

Alfa AF: 0.000381 Hom.: 0

Bravo AF: 0.000608

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Polyglucosan body myopathy type 1 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Nov 25, 2023

- -

RBCK1-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 14, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.50
Cadd	Benign	11
Dann	Benign	0.80

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.0019
dbscSNV1_RF	Benign	0.14
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: rs149038161; hg19: chr20-407953;