rs1334913120

chr6-51934323-CT-C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Moderate PM2 PP3_Moderate PP5_Very_Strong

The NM_138694.4(PKHD1):c.5909-2del variant causes a splice acceptor change. The variant allele was found at a frequency of 0.000000687 in 1,454,818 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: PKHD1 NM_138694.4 splice_acceptor
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 5.99

Genes affected

PKHD1 (HGNC:9016): (PKHD1 ciliary IPT domain containing fibrocystin/polyductin) The protein encoded by this gene is predicted to have a single transmembrane (TM)-spanning domain and multiple copies of an immunoglobulin-like plexin-transcription-factor domain. Alternative splicing results in two transcript variants encoding different isoforms. Other alternatively spliced transcripts have been described, but the full length sequences have not been determined. Several of these transcripts are predicted to encode truncated products which lack the TM and may be secreted. Mutations in this gene cause autosomal recessive polycystic kidney disease, also known as polycystic kidney and hepatic disease-1. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.017341513 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.4, offset of 27, new splice context is: gctgattttcatggccccAGgac. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 6-51934323-CT-C is Pathogenic according to our data. Variant chr6-51934323-CT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 551218.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PKHD1	NM_138694.4	c.5909-2del		splice_acceptor_variant		ENST00000371117.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PKHD1	ENST00000371117.8	c.5909-2del		splice_acceptor_variant		1	NM_138694.4	P2
PKHD1	ENST00000340994.4	c.5909-2del		splice_acceptor_variant		5		A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1454818 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 724096

Gnomad4 AFR exome AF: 0.0000300

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.0000113

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive polycystic kidney disease Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Mar 24, 2017	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Sep 27, 2023	This sequence change affects a splice site in intron 36 of the PKHD1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in PKHD1 are known to be pathogenic (PMID: 19940839). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with autosomal recessive polycystic kidney disease (PMID: 25114813). ClinVar contains an entry for this variant (Variation ID: 551218). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 26, 2023

Canonical splice site variant expected to result in aberrant splicing, although in the absence of functional evidence the actual effect of this sequence change is unknown; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 25114813) -

PKHD1-related disorder Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 11, 2023

The PKHD1 c.5909-2delA variant is predicted to result in a deletion affecting a canonical splice site. This variant has been reported to be pathogenic for autosomal recessive polycystic kidney disease (ARPKD) (Thakur et al. 2014. PubMed ID: 25114813). To our knowledge, this variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. In ClinVar, this variant has been interpreted as likely pathogenic (https://www.ncbi.nlm.nih.gov/clinvar/variation/551218/). This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.37		Position offset: -9
DS_AL_spliceai		0.99		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1334913120; hg19: chr6-51799121;