X-22247901-G-C

Variant names:

• chrX-22247901-G-C
• rs1057517981
• NM_000444.6:c.2198G>C

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000444.6(PHEX):​c.2198G>C​(p.Cys733Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C733F) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 23)
• Consequence: PHEX NM_000444.6 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 6.67
• Publications: 6 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 17 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-22247901-G-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 803777.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 135 curated pathogenic missense variants (we use a threshold of 10). The gene has 25 curated benign missense variants. Gene score misZ: 1.7091 (below the threshold of 3.09). Trascript score misZ: NaN (below the threshold of 3.09). GenCC associations: The gene is linked to X-linked dominant hypophosphatemic rickets.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant X-22247901-G-C is Pathogenic according to our data. Variant chrX-22247901-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 438487.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.2198G>C	p.Cys733Ser	missense_variant	Exon 22 of 22	ENST00000379374.5	NP_000435.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PHEX	ENST00000379374.5	c.2198G>C	p.Cys733Ser	missense_variant	Exon 22 of 22	1	NM_000444.6	ENSP00000368682.4

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial X-linked hypophosphatemic vitamin D refractory rickets Pathogenic:1

Jun 12, 2017

Institute of Human Genetics Munich, TUM University Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:1

May 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces cysteine, which is neutral and slightly polar, with serine, which is neutral and polar, at codon 733 of the PHEX protein (p.Cys733Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with X-linked hypophosphatemia (XLH) (PMID: 10439971; Invitae). ClinVar contains an entry for this variant (Variation ID: 438487). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PHEX protein function with a positive predictive value of 95%. This variant disrupts the p.Cys733 amino acid residue in PHEX. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 22527485, 25839938). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.85	D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.3	H
PhyloP100		6.7
PrimateAI	Uncertain	0.59	T
PROVEAN	Pathogenic	-9.4	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.96
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.99
gMVP		0.94
Mutation Taster		=3/97	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1057517981; hg19: chrX-22266018;