6-57188644-T-C

Position:

• chr6-57188644-T-C

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BS1_Supporting

The NM_016277.5(RAB23):​c.*1817A>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000223 in 152,288 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00022 (0 hom., cov: 33)
  • Failed GnomAD Quality Control
• Consequence: RAB23 NM_016277.5 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.18

Genes affected

BAG2 (HGNC:938): (BAG cochaperone 2) BAG proteins compete with Hip for binding to the Hsc70/Hsp70 ATPase domain and promote substrate release. All the BAG proteins have an approximately 45-amino acid BAG domain near the C terminus but differ markedly in their N-terminal regions. The predicted BAG2 protein contains 211 amino acids. The BAG domains of BAG1, BAG2, and BAG3 interact specifically with the Hsc70 ATPase domain in vitro and in mammalian cells. All 3 proteins bind with high affinity to the ATPase domain of Hsc70 and inhibit its chaperone activity in a Hip-repressible manner. [provided by RefSeq, Jul 2008]

RAB23 (HGNC:14263): (RAB23, member RAS oncogene family) This gene encodes a small GTPase of the Ras superfamily. Rab proteins are involved in the regulation of diverse cellular functions associated with intracellular membrane trafficking, including autophagy and immune response to bacterial infection. The encoded protein may play a role in central nervous system development by antagonizing sonic hedgehog signaling. Disruption of this gene has been implicated in Carpenter syndrome as well as cancer. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000223 (34/152288) while in subpopulation EAS AF= 0.00309 (16/5184). AF 95% confidence interval is 0.00194. There are 0 homozygotes in gnomad4. There are 18 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BAG2	NM_004282.4	c.*4454T>C		3_prime_UTR_variant	3/3	ENST00000370693.5
RAB23	NM_016277.5	c.*1817A>G		3_prime_UTR_variant	7/7	ENST00000468148.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BAG2	ENST00000370693.5	c.*4454T>C		3_prime_UTR_variant	3/3	1	NM_004282.4	P1
RAB23	ENST00000468148.6	c.*1817A>G		3_prime_UTR_variant	7/7	1	NM_016277.5	P1

Frequencies

GnomAD3 genomes AF: 0.000223 AC: 34 AN: 152170 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000217

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000262

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00308

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000588

Gnomad OTH AF: 0.000478

GnomAD4 exome Data not reliable, filtered out with message: AC0 AC: 0 AN: 0 Hom.: 0 Cov.: 0 AC XY: 0 AN XY: 0

GnomAD4 genome AF: 0.000223 AC: 34 AN: 152288 Hom.: 0 Cov.: 33 AF XY: 0.000242 AC XY: 18 AN XY: 74470

Gnomad4 AFR AF: 0.000217

Gnomad4 AMR AF: 0.000262

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00309

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.000473

Bravo AF: 0.000253

Asia WGS AF: 0.00116 AC: 4 AN: 3472

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

RAB23-related Carpenter syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
CADD	Benign	0.26
DANN	Benign	0.81

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: rs368441472; hg19: chr6-57053442;