rs1553360075

Variant names:

• chr2-44346369-CTTGT-C
• rs1553360075
• ENST00000260648.10:c.237_240delACAA

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_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
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 1.56
• Publications: 0 publications found

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

ACMG classification

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	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	c.-31_-28delACAA		5_prime_UTR_variant	Exon 2 of 14	1	NM_001171613.2	ENSP00000387095.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460600 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 726620

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

African (AFR) AF: 0.00 AC: 0 AN: 33418

American (AMR) AF: 0.00 AC: 0 AN: 44582

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26096

East Asian (EAS) AF: 0.00 AC: 0 AN: 39550

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86094

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53266

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111500

Other (OTH) AF: 0.00 AC: 0 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.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

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)

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

Other links and lift over

dbSNP: rs1553360075; hg19: chr2-44573508;