rs786204617

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1PM5PP3_StrongPP5_Very_Strong

The NM_000478.6(ALPL):c.667C>T(p.Arg223Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,798 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R223Q) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

ALPL
NM_000478.6 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 1.79

Variant links:

Genes affected

ALPL (HGNC:438): (alkaline phosphatase, biomineralization associated) This gene encodes a member of the alkaline phosphatase family of proteins. There are at least four distinct but related alkaline phosphatases: intestinal, placental, placental-like, and liver/bone/kidney (tissue non-specific). The first three are located together on chromosome 2, while the tissue non-specific form is located on chromosome 1. The product of this gene is a membrane bound glycosylated enzyme that is not expressed in any particular tissue and is, therefore, referred to as the tissue-nonspecific form of the enzyme. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed to generate the mature enzyme. This enzyme may play a role in bone mineralization. Mutations in this gene have been linked to hypophosphatasia, a disorder that is characterized by hypercalcemia and skeletal defects. [provided by RefSeq, Oct 2015]

ALPL links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 16 ACMG points.

PM1

In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_000478.6

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-21568123-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 381586.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.991

PP5

Variant 1-21568122-C-T is Pathogenic according to our data. Variant chr1-21568122-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 189001.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-21568122-C-T is described in Lovd as [Pathogenic]. Variant chr1-21568122-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALPL	NM_000478.6 linkuse as main transcript	c.667C>T	p.Arg223Trp	missense_variant	7/12	ENST00000374840.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALPL	ENST00000374840.8 linkuse as main transcript	c.667C>T	p.Arg223Trp	missense_variant	7/12	1	NM_000478.6	P1	P05186-1
ALPL	ENST00000374832.5 linkuse as main transcript	c.667C>T	p.Arg223Trp	missense_variant	7/12	2		P1	P05186-1
ALPL	ENST00000540617.5 linkuse as main transcript	c.502C>T	p.Arg168Trp	missense_variant	6/11	2			P05186-3
ALPL	ENST00000539907.5 linkuse as main transcript	c.436C>T	p.Arg146Trp	missense_variant	5/10	2			P05186-2

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

151934

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251478

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135916

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1461864

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727230

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000540

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

151934

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74184

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000151

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hypophosphatasia

Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 22, 2023	Variant summary: ALPL c.667C>T (p.Arg223Trp) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251478 control chromosomes (gnomAD). c.667C>T (also known as R206W) has been reported in the literature in multiple bi-allelic individuals affected with Hypophosphatasia (example: Mornet_1998, Brun-Heath_2005, Collman_2009, Orimo_2009, Hofmann_2013, McKiernan_2017, DelAngel_2020), however some of these individual had variants classified as VUS or likely benign in trans (Orimo_2009, Brun-Heath_2005). Multiple publications have reported experimental evidence evaluating an impact on protein function. All of these studies have shown variant effect results in <10% of normal activity (example: Hofmann_2013, Orimo_2009, Brun-Heath_2005). The following publications have been ascertained in the context of this evaluation (PMID: 23454488, 11760847, 18769927, 9781036, 28401263, 15694177, 32160374). Three submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	DASA	Mar 05, 2022	Well-established in vitro or in vivo functional studies supportive of a damaging effect on the gene or gene product (PMID: 23454488) - PS3_moderate.The c.667C>T;p.(Arg223Trp) missense variant has been observed in affected individual(s) and ClinVar contains an entry for this variant (ClinVar ID: 189001; PMID: 24100244; PMID: 23454488; PMID: 20383509) - PS4. The variant is located in a mutational hot spot and/or critical and well-established functional domain (Alk-phosphatase) - PM1. The variant is present at low allele frequencies population databases (rs766076920 – gnomAD 0.0001061%; ABraOM no frequency - http://abraom.ib.usp.br/) - PM2_supporting. The p.(Arg223Trp) was detected in trans with a pathogenic variant (PMID: 24100244; PMID: 23454488; PMID: 20383509) - PM3. Pathogenic missense variant in this residue have been reported (ClinVar ID: 381586) - PM5. Multiple lines of computational evidence support a deleterious effect on the gene or gene product - PP3. The variant was identified in an individual with a highly specific phenotype for the condition -PP4. In summary, the currently available evidence indicates that the variant is pathogenic. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	May 18, 2021	- -

Infantile hypophosphatasia

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

literature only

Counsyl

Oct 09, 2014

- -

Adult hypophosphatasia

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Feb 08, 2023

- -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 10, 2024

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 223 of the ALPL protein (p.Arg223Trp). This variant is present in population databases (rs766076920, gnomAD 0.003%). This missense change has been observed in individual(s) with hypophosphatasia (PMID: 11760847, 23454488, 24100244). This variant is also known as p.Arg206Trp. ClinVar contains an entry for this variant (Variation ID: 189001). 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 ALPL protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects ALPL function (PMID: 11760847, 23454488). This variant disrupts the p.Arg223 amino acid residue in ALPL. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11855933, 15694177, 23509830, 24100244). 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

0.85

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.51

Cadd

Pathogenic

Dann

Uncertain

1.0

DEOGEN2

Pathogenic

0.97

D;.;.;D

Eigen

Uncertain

0.61

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Uncertain

0.93

M_CAP

Pathogenic

0.47

MetaRNN

Pathogenic

0.99

D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.0

M;.;.;M

MutationTaster

Benign

1.0

D;D;D;D;D

PrimateAI

Uncertain

0.72

PROVEAN

Pathogenic

-7.4

D;D;D;D

REVEL

Pathogenic

0.95

Sift

Pathogenic

0.0

D;D;D;D

Sift4G

Pathogenic

0.0

D;D;D;D

Polyphen

1.0

D;.;.;D

Vest4

0.98

MutPred

0.94

Gain of catalytic residue at M226 (P = 0.0045);.;.;Gain of catalytic residue at M226 (P = 0.0045);

MVP

0.98

MPC

1.3

ClinPred

1.0

GERP RS

3.8

Varity_R

0.90

gMVP

0.97

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over