chr20-427412-AA-CT

Variant names:

• chr20-427412-AA-CT
• NM_031229.4:c.1129_1130delAAinsCT

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.

The NM_031229.4(RBCK1):​c.1129_1130delAAinsCT​(p.Lys377Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: RBCK1 NM_031229.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.77
• Publications: 0 publications found

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]

TBC1D20 Gene-Disease associations (from GenCC):

• Warburg micro syndrome 4

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• Warburg micro syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RBCK1	NM_031229.4	c.1129_1130delAAinsCT	p.Lys377Leu	missense_variant		ENST00000356286.10	NP_112506.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RBCK1	ENST00000356286.10	c.1129_1130delAAinsCT	p.Lys377Leu	missense_variant		1	NM_031229.4	ENSP00000348632.6

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Polyglucosan body myopathy type 1 Uncertain:1

Jun 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: "Benign"; 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. This variant has not been reported in the literature in individuals affected with RBCK1-related conditions. This sequence change replaces lysine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 377 of the RBCK1 protein (p.Lys377Leu). Information on the frequency of this variant in the gnomAD database is not available, as this variant may be reported differently in the database. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.8

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

hg19: chr20-408056;