chr17-2672762-G-A

Position:

• chr17-2672762-G-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PP3 PP5_Very_Strong

The ENST00000397195.10(PAFAH1B1):​c.671+5G>A variant causes a splice donor 5th base, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PAFAH1B1 ENST00000397195.10 splice_donor_5th_base, intron
• Scores: Splicing: ADA: 0.9964
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.60

Genes affected

PAFAH1B1 (HGNC:8574): (platelet activating factor acetylhydrolase 1b regulatory subunit 1) This locus was identified as encoding a gene that when mutated or lost caused the lissencephaly associated with Miller-Dieker lissencephaly syndrome. This gene encodes the non-catalytic alpha subunit of the intracellular Ib isoform of platelet-activating factor acteylhydrolase, a heterotrimeric enzyme that specifically catalyzes the removal of the acetyl group at the SN-2 position of platelet-activating factor (identified as 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine). Two other isoforms of intracellular platelet-activating factor acetylhydrolase exist: one composed of multiple subunits, the other, a single subunit. In addition, a single-subunit isoform of this enzyme is found in serum. [provided by RefSeq, Apr 2009]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Multiple lines of computational evidence support a deleterious effect 4: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai, phyloP100way_vertebrate [when BayesDel_noAF, Cadd was below the threshold]
• PP5: Variant 17-2672762-G-A is Pathogenic according to our data. Variant chr17-2672762-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 159537.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PAFAH1B1	NM_000430.4	c.671+5G>A		splice_donor_5th_base_variant, intron_variant		ENST00000397195.10	NP_000421.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PAFAH1B1	ENST00000397195.10	c.671+5G>A		splice_donor_5th_base_variant, intron_variant		1	NM_000430.4	ENSP00000380378	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 24

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lissencephaly due to LIS1 mutation Pathogenic:2

Likely pathogenic, criteria provided, single submitter	research	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	-	The heterozygous c.671+5G>A variant was identified by our study in one individual with Lissencephaly. Trio analysis showed this variant to be de novo. This variant is located in the extended slice site According to alamut it eliminates a splice donor site 5 nucleotides from the canonical splice site, and weakens the splice donor site of intron 7 by 2/5 splice predictors. ESEfinder predicts the splice donor site to be unaffected but the donor site 5 nucleotides away is eliminated. This variant was absent from large population studies but it was entered in ClinVar by UChicago as likely pathogenic. They reported that they identified this variant in one individual with Lissencephaly. In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 08, 2013	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.18
CADD	Benign	19
DANN	Uncertain	0.98

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.78		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.78		Position offset: -5

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

Publications

LitVar

Other links and lift over

dbSNP: rs587784280; hg19: chr17-2576056;