chr20-45898770-G-A

Position:

• chr20-45898770-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_006227.4(PLTP):​c.*171C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000215 in 798,424 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 0.00014 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00023 (0 hom.)
• Consequence: PLTP NM_006227.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.328

Genes affected

CTSA (HGNC:9251): (cathepsin A) This gene encodes a member of the peptidase S10 family of serine carboxypeptidases. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed to generate two chains that comprise the heterodimeric active enzyme. This enzyme possesses deamidase, esterase and carboxypeptidase activities and acts as a scaffold in the lysosomal multienzyme complex. Mutations in this gene are associated with galactosialidosis. [provided by RefSeq, Nov 2015]

PLTP (HGNC:9093): (phospholipid transfer protein) The protein encoded by this gene is one of at least two lipid transfer proteins found in human plasma. The encoded protein transfers phospholipids from triglyceride-rich lipoproteins to high density lipoprotein (HDL). In addition to regulating the size of HDL particles, this protein may be involved in cholesterol metabolism. At least two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.63).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTSA	NM_000308.4	c.*320G>A		3_prime_UTR_variant	15/15	ENST00000646241.3
PLTP	NM_006227.4	c.*171C>T		3_prime_UTR_variant	16/16	ENST00000372431.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PLTP	ENST00000372431.8	c.*171C>T		3_prime_UTR_variant	16/16	1	NM_006227.4	P1
CTSA	ENST00000646241.3	c.*320G>A		3_prime_UTR_variant	15/15		NM_000308.4

Frequencies

GnomAD3 genomes AF: 0.000145 AC: 22 AN: 152170 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000385

Gnomad SAS AF: 0.00145

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000882

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.000232 AC: 150 AN: 646136 Hom.: 0 Cov.: 9 AF XY: 0.000279 AC XY: 93 AN XY: 332962

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000261

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000280

Gnomad4 SAS exome AF: 0.00122

Gnomad4 FIN exome AF: 0.0000317

Gnomad4 NFE exome AF: 0.000150

Gnomad4 OTH exome AF: 0.000153

GnomAD4 genome AF: 0.000144 AC: 22 AN: 152288 Hom.: 0 Cov.: 32 AF XY: 0.000188 AC XY: 14 AN XY: 74456

Gnomad4 AFR AF: 0.0000481

Gnomad4 AMR AF: 0.000327

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000386

Gnomad4 SAS AF: 0.00145

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000882

Gnomad4 OTH AF: 0.00

Bravo AF: 0.000144

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Combined deficiency of sialidase AND beta galactosidase Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 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	-0.63
CADD	Benign	7.0
DANN	Benign	0.91
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

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: rs568876316; hg19: chr20-44527409;