6-51856068-G-C

Variant names:

• chr6-51856068-G-C
• rs78361537
• NM_138694.4:c.7736C>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_138694.4(PKHD1):​c.7736C>G​(p.Ala2579Gly) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000695 in 1,438,266 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A2579V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: PKHD1 NM_138694.4 missense, splice_region
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.0160
• Publications: 0 publications found

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]

PKHD1 Gene-Disease associations (from GenCC):

• autosomal recessive polycystic kidney disease

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Myriad Women’s Health, Orphanet
• polycystic kidney disease 4

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine, Genomics England PanelApp
• Caroli disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_138694.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.11835018).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_138694.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PKHD1	NM_138694.4	MANE Select	c.7736C>G	p.Ala2579Gly	missense splice_region	Exon 49 of 67	NP_619639.3
	PKHD1	NM_170724.3		c.7736C>G	p.Ala2579Gly	missense splice_region	Exon 49 of 61	NP_733842.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PKHD1	ENST00000371117.8	TSL:1 MANE Select	c.7736C>G	p.Ala2579Gly	missense splice_region	Exon 49 of 67	ENSP00000360158.3
	PKHD1	ENST00000340994.4	TSL:5	c.7736C>G	p.Ala2579Gly	missense splice_region	Exon 49 of 61	ENSP00000341097.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.95e-7 AC: 1 AN: 1438266 Hom.: 0 Cov.: 29 AF XY: 0.00000139 AC XY: 1 AN XY: 717164

⚠️ 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: 32864

American (AMR) AF: 0.00 AC: 0 AN: 44660

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26018

East Asian (EAS) AF: 0.00 AC: 0 AN: 39292

South Asian (SAS) AF: 0.00 AC: 0 AN: 85428

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5732

European-Non Finnish (NFE) AF: 9.16e-7 AC: 1 AN: 1091354

Other (OTH) AF: 0.00 AC: 0 AN: 59510

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.079	T
BayesDel_noAF	Benign	-0.35
CADD	Benign	1.6
DANN	Benign	0.91
DEOGEN2	Benign	0.27	T
Eigen	Benign	-0.76
Eigen_PC	Benign	-0.88
FATHMM_MKL	Benign	0.14	N
LIST_S2	Benign	0.66	T
M_CAP	Benign	0.066	D
MetaRNN	Benign	0.12	T
MetaSVM	Benign	-0.78	T
MutationAssessor	Uncertain	2.2	M
PhyloP100		0.016
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.7	N
REVEL	Benign	0.16
Sift	Benign	0.19	T
Sift4G	Benign	0.29	T
Polyphen		0.32	B
Vest4		0.27
MutPred		0.34		Gain of sheet (P = 0.0477)
MVP		0.78
MPC		0.13
ClinPred		0.079	T
GERP RS		-2.7
Varity_R		0.077
gMVP		0.35
Mutation Taster		=74/26	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs78361537; hg19: chr6-51720866;