rs1555394745

Positions:

• chr15-55234915-TCA-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_183235.3(RAB27A):​c.18_19delTG​(p.Tyr6fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: RAB27A NM_183235.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.81

Genes affected

RAB27A (HGNC:9766): (RAB27A, member RAS oncogene family) The protein encoded by this gene belongs to the small GTPase superfamily, Rab family. The protein is membrane-bound and may be involved in protein transport and small GTPase mediated signal transduction. Mutations in this gene are associated with Griscelli syndrome type 2. Alternative splicing occurs at this locus and four transcript variants encoding the same protein have been identified. [provided by RefSeq, Jul 2008]

RAB27A (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 4 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-55234915-TCA-T is Pathogenic according to our data. Variant chr15-55234915-TCA-T is described in ClinVar as [Pathogenic]. Clinvar id is 451279.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
RAB27A	NM_183235.3	c.18_19delTG	p.Tyr6fs	frameshift_variant	3/7	ENST00000336787.6	NP_899058.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
RAB27A	ENST00000336787.6	c.18_19delTG	p.Tyr6fs	frameshift_variant	3/7	1	NM_183235.3	ENSP00000337761.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249884 Hom.: 0 AF XY: 0.00000740 AC XY: 1 AN XY: 135134

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: 0.00000885

Gnomad OTH exome AF: 0.00

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

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Aug 07, 2017

The c.18_19delTG variant in the RAB27A gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. The c.18_19delTG variant causes a frameshift starting with codon Tyrosine 6, and changes this amino acid to a premature Stop codon, denoted p.Tyr6Ter. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.18_19delTG variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). We interpret c.18_19delTG as a pathogenic variant. -

Griscelli syndrome type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 25, 2021

For these reasons, this variant has been classified as Pathogenic. This variant has not been reported in the literature in individuals with RAB27A-related conditions. ClinVar contains an entry for this variant (Variation ID: 451279). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Tyr6*) in the RAB27A gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in RAB27A are known to be pathogenic (PMID: 10835631, 23160464). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1555394745; hg19: chr15-55527113;