6-52024664-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_138694.4(PKHD1):c.5146G>A(p.Val1716Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000616 in 1,461,868 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V1716F) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: PKHD1 NM_138694.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.508

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 Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 4 uncertain in NM_138694.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.13957733).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PKHD1	NM_138694.4	c.5146G>A	p.Val1716Ile	missense_variant	32/67	ENST00000371117.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PKHD1	ENST00000371117.8	c.5146G>A	p.Val1716Ile	missense_variant	32/67	1	NM_138694.4	P2
PKHD1	ENST00000340994.4	c.5146G>A	p.Val1716Ile	missense_variant	32/61	5		A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000159 AC: 4 AN: 251274 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135808

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1461868 Hom.: 0 Cov.: 34 AF XY: 0.00000550 AC XY: 4 AN XY: 727242

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.000224 Hom.: 0

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 21, 2023

The c.5146G>A (p.V1716I) alteration is located in exon 32 (coding exon 31) of the PKHD1 gene. This alteration results from a G to A substitution at nucleotide position 5146, causing the valine (V) at amino acid position 1716 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jul 15, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.41
Cadd	Benign	7.7
Dann	Benign	0.96
DEOGEN2	Benign	0.27	T;.
Eigen	Benign	-0.69
Eigen_PC	Benign	-0.72
FATHMM_MKL	Benign	0.087	N
LIST_S2	Benign	0.72	T;T
M_CAP	Benign	0.048	D
MetaRNN	Benign	0.14	T;T
MetaSVM	Benign	-0.51	T
MutationAssessor	Benign	1.7	L;L
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-0.86	N;N
REVEL	Benign	0.083
Sift	Benign	0.048	D;T
Sift4G	Benign	0.21	T;T
Polyphen		0.079	B;B
Vest4		0.17
MutPred		0.35		Loss of methylation at R1717 (P = 0.1056);Loss of methylation at R1717 (P = 0.1056);
MVP		0.77
MPC		0.057
ClinPred		0.061	T
GERP RS		2.9
Varity_R		0.078
gMVP		0.20

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: rs751058491; hg19: chr6-51889462; COSMIC: COSV61868269;