chr9-95506601-T-C

Position:

• chr9-95506601-T-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000264.5(PTCH1):​c.202-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PTCH1 NM_000264.5 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.39

Genes affected

PTCH1 (HGNC:9585): (patched 1) This gene encodes a member of the patched family of proteins and a component of the hedgehog signaling pathway. Hedgehog signaling is important in embryonic development and tumorigenesis. The encoded protein is the receptor for the secreted hedgehog ligands, which include sonic hedgehog, indian hedgehog and desert hedgehog. Following binding by one of the hedgehog ligands, the encoded protein is trafficked away from the primary cilium, relieving inhibition of the G-protein-coupled receptor smoothened, which results in activation of downstream signaling. Mutations of this gene have been associated with basal cell nevus syndrome and holoprosencephaly. [provided by RefSeq, Aug 2017]

PTCH1 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-95506601-T-C is Pathogenic according to our data. Variant chr9-95506601-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 237465.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-95506601-T-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PTCH1	NM_000264.5	c.202-2A>G		splice_acceptor_variant, intron_variant		ENST00000331920.11	NP_000255.2
PTCH1	NM_001083603.3	c.199-2A>G		splice_acceptor_variant, intron_variant		ENST00000437951.6	NP_001077072.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PTCH1	ENST00000331920.11	c.202-2A>G		splice_acceptor_variant, intron_variant		5	NM_000264.5	ENSP00000332353.6
PTCH1	ENST00000437951.6	c.199-2A>G		splice_acceptor_variant, intron_variant		5	NM_001083603.3	ENSP00000389744.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gorlin syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 19, 2023

Disruption of this splice site has been observed in individuals with clinical features of basal cell nevus syndrome (PMID: 29575684; Invitae). This sequence change affects an acceptor splice site in intron 1 of the PTCH1 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 PTCH1 are known to be pathogenic (PMID: 16301862, 16419085). This variant is not present in population databases (gnomAD no frequency). ClinVar contains an entry for this variant (Variation ID: 237465). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 01, 2022

Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 29575684, 28328109) -

Basal cell nevus syndrome 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

St. Jude Molecular Pathology, St. Jude Children's Research Hospital

Jan 03, 2022

The PTCH1 c.202-2A>G intronic change results from an A to G substitution at the -2 position of intron 1 of the PTCH1 gene. This variant disrupts the native splice site at c.202 resulting in out-of-frame alternative splicing between exons 1 and 3 and skipping of exon 2. This variant has been reported in individuals with nevoid basal cell carcinoma syndrome (PMID: 29575684, 28328109). It has also been identified in an individual with a SHH-medulloblastoma with an increased variant allele frequency in the tumor (internal data). This variant is absent in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/). In summary, this variant meets criteria to be classified as pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 25, 2019

The c.202-2A>G intronic pathogenic mutation results from an A to G substitution two nucleotides upstream from coding exon 2 in the PTCH1 gene. This alteration has been reported in a cohort of patients referred for testing for nevoid basal cell carcinoma syndrome (NBCCS) (Reinders MG et al. Mol Genet Genomic Med. 2018 05;6:409-415). Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to abolish the native splice acceptor site; however, direct evidence is unavailable. In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	33
DANN	Uncertain	0.98
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.97	D
GERP RS		4.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.91		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.91		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs878853849; hg19: chr9-98268883;