X-22219104-G-C

Variant names:

• chrX-22219104-G-C
• rs886041296
• NM_000444.6:c.1768+1G>C

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000444.6(PHEX):​c.1768+1G>C variant causes a splice donor, 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: 24)
• Consequence: PHEX NM_000444.6 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 8.63
• Publications: 0 publications found

Genes affected

PHEX (HGNC:8918): (phosphate regulating endopeptidase X-linked) The protein encoded by this gene is a transmembrane endopeptidase that belongs to the type II integral membrane zinc-dependent endopeptidase family. The protein is thought to be involved in bone and dentin mineralization and renal phosphate reabsorption. Mutations in this gene cause X-linked hypophosphatemic rickets. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2013]

PTCHD1-AS (HGNC:37703): (PTCHD1 antisense RNA (head to head))

ACMG classification

Our verdict: Pathogenic. The variant received 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 X-22219104-G-C is Pathogenic according to our data. Variant chrX-22219104-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 279976.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PHEX	NM_000444.6	c.1768+1G>C		splice_donor_variant, intron_variant	Intron 17 of 21	ENST00000379374.5	NP_000435.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PHEX	ENST00000379374.5	c.1768+1G>C		splice_donor_variant, intron_variant	Intron 17 of 21	1	NM_000444.6	ENSP00000368682.4

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Cov.: 22

GnomAD4 genome Cov.: 24

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Sep 17, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 17 of the PHEX 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 PHEX are known to be pathogenic (PMID: 9097956, 9106524, 19219621). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with X-linked hypophosphatemic rickets (PMID: 18625346, 24836714). ClinVar contains an entry for this variant (Variation ID: 279976). 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. -

Oct 12, 2016

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1768+1 G>C splice site variant in the PHEX gene has been previously reported in association with X-linked hypophosphatemic rickets (Ichikawa et al., 2008). This pathogenic variant destroys the canonical splice donor site in intron 17, and is expected to cause abnormal gene splicing. Additionally, the variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. -

Hypophosphatemic rickets Pathogenic:1

Feb 07, 2022

Laboratory of Cyto-molecular Genetics, Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	33
DANN	Uncertain	1.0
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		8.6
GERP RS		5.9
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.91		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.91		Position offset: -1

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

Other links and lift over

dbSNP: rs886041296; hg19: chrX-22237221;