Genetic Variant ENST00000260648.10:c.237_240delACAA (chr2-44346369-CTTGT-C) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The ENST00000260648.10(PREPL):c.237_240delACAA(p.Gln80LysfsTer16) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,600 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

PREPL
ENST00000260648.10 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 1.56

Publications

0 publications found

Variant links:

Genes affected

PREPL (HGNC:30228): (prolyl endopeptidase like) The protein encoded by this gene belongs to the prolyl oligopeptidase subfamily of serine peptidases. Mutations in this gene have been associated with hypotonia-cystinuria syndrome, also known as the 2p21 deletion syndrome. Several alternatively spliced transcript variants encoding either the same or different isoforms have been described for this gene.[provided by RefSeq, Jan 2010]

PREPL Gene-Disease associations (from GenCC):

hypotonia-cystinuria syndrome
Inheritance: AR Classification: STRONG Submitted by: G2P
myasthenic syndrome, congenital, 22
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, Ambry Genetics, Illumina

PREPL links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-44346369-CTTGT-C is Pathogenic according to our data. Variant chr2-44346369-CTTGT-C is described in ClinVar as Pathogenic. ClinVar VariationId is 478314.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PREPL	NM_001171613.2 link	c.-31_-28delACAA		5_prime_UTR_variant	Exon 2 of 14	ENST00000409411.6	NP_001165084.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PREPL	ENST00000409411.6 link	c.-31_-28delACAA		5_prime_UTR_variant	Exon 2 of 14	1	NM_001171613.2	ENSP00000387095.2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1460600

Hom.:

AF XY:

0.00000138

AC XY:

AN XY:

726620

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33418

American (AMR)

AF:

0.00

AC:

AN:

44582

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26096

East Asian (EAS)

AF:

0.00

AC:

AN:

39550

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86094

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53266

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111500

Other (OTH)

AF:

0.00

AC:

AN:

60334

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Myasthenic syndrome, congenital, 22

Pathogenic:1

Oct 21, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Gln80Lysfs*16) in the PREPL gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PREPL are known to be pathogenic (PMID: 24610330, 28726805, 29913539). This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with PREPL-related conditions. ClinVar contains an entry for this variant (Variation ID: 478314). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

1.6

Mutation Taster

=13/187

disease causing (fs/PTC)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over