rs753008447

Positions:

• chr15-91005053-A-C
• chr15-91005053-A-G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1 PM2 PP3_Strong

The NM_018668.5(VPS33B):​c.1170+2T>G variant causes a splice donor change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000022 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: VPS33B NM_018668.5 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.16

Genes affected

VPS33B (HGNC:12712): (VPS33B late endosome and lysosome associated) Vesicle mediated protein sorting plays an important role in segregation of intracellular molecules into distinct organelles. Genetic studies in yeast have identified more than 40 vacuolar protein sorting (VPS) genes involved in vesicle transport to vacuoles. This gene is a member of the Sec-1 domain family, and encodes the human ortholog of rat Vps33b which is homologous to the yeast class C Vps33 protein. The mammalian class C vacuolar protein sorting proteins are predominantly associated with late endosomes/lysosomes, and like their yeast counterparts, may mediate vesicle trafficking steps in the endosome/lysosome pathway. Mutations in this gene are associated with arthrogryposis-renal dysfunction-cholestasis syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.4, offset of 44, new splice context is: gagGTgggg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
VPS33B	NM_018668.5	c.1170+2T>G		splice_donor_variant		ENST00000333371.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
VPS33B	ENST00000333371.8	c.1170+2T>G		splice_donor_variant		1	NM_018668.5	P1
VPS33B	ENST00000535906.1	c.1089+2T>G		splice_donor_variant		2
VPS33B	ENST00000574755.5	c.*865+2T>G		splice_donor_variant, NMD_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.0000219 AC: 32 AN: 1461466 Hom.: 0 Cov.: 33 AF XY: 0.0000179 AC XY: 13 AN XY: 727046

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: 0.0000348

Gnomad4 FIN exome AF: 0.000452

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome Cov.: 32

ExAC AF: 0.00118 AC: 143

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	-0.040
CADD	Uncertain	25
DANN	Uncertain	0.99
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.96	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.97		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.97		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs753008447; hg19: chr15-91548283;