rs121918000

Variant summary

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

The NM_000478.6(ALPL):​c.535G>A​(p.Ala179Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,461,742 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. A179V) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

ALPL
NM_000478.6 missense

Scores

13
5
1

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10

Conservation

PhyloP100: 9.55
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]

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 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000478.6
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-21564104-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1520525.Status of the report is criteria_provided_single_submitter, 1 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.993
PP5
Variant 1-21564103-G-A is Pathogenic according to our data. Variant chr1-21564103-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 13662.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-21564103-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
ALPLNM_000478.6 linkc.535G>A p.Ala179Thr missense_variant Exon 6 of 12 ENST00000374840.8 NP_000469.3 P05186-1A0A024RAB4

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ALPLENST00000374840.8 linkc.535G>A p.Ala179Thr missense_variant Exon 6 of 12 1 NM_000478.6 ENSP00000363973.3 P05186-1

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD3 exomes
AF:
0.0000119
AC:
3
AN:
251074
Hom.:
0
AF XY:
0.0000221
AC XY:
3
AN XY:
135762
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000264
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000479
AC:
7
AN:
1461742
Hom.:
0
Cov.:
32
AF XY:
0.00000825
AC XY:
6
AN XY:
727192
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:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000630
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:10
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Pathogenic:4
Jan 06, 2022
Revvity Omics, Revvity
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Oct 24, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 179 of the ALPL protein (p.Ala179Thr). This variant is present in population databases (rs121918000, gnomAD 0.003%). This missense change has been observed in individual(s) with clinical features of hypophosphatasia (PMID: 3174660, 11438998, 32160374; internal data). This variant is also known as Ala162Thr. ClinVar contains an entry for this variant (Variation ID: 13662). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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: 9562633, 12162492, 23509830, 32160374). For these reasons, this variant has been classified as Pathogenic. -

May 05, 2023
GeneDx
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Identified in patients with childhood hypophophatasia who harbored a second ALPL variant of unknown phase in published literature (Whyte et al., 2015; Genest et al., 2018); Reported in a heterozygous adult patient with features of hypophosphatasia in published literature (Schmidt et al., 2019); Published functional studies demonstrate a damaging effect on protein trafficking and enzyme activity (Weiss et al., 1988; Shibata et al., 1998; Di Mauro et al., 2002; Zhu et al., 2012); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Also denoted as A162T due to alternative nomenclature; This variant is associated with the following publications: (PMID: 23509830, 9562633, 28991257, 23791648, 31400546, 3174660, 12162492, 11438998, 25731960, 29774402, 31485555, 32368696, 32160374) -

Oct 01, 2018
CeGaT Center for Human Genetics Tuebingen
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Infantile hypophosphatasia Pathogenic:2
Aug 01, 2014
Counsyl
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: literature only

- -

Oct 30, 2024
OMIM
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: literature only

- -

Hypophosphatasia Pathogenic:2
Aug 24, 2021
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: ALPL c.535G>A (p.Ala179Thr) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 251074 control chromosomes (gnomAD). c.535G>A has been reported in the literature in multiple compound heterozygous and homozygous individuals affected with Hypophosphatasia (e.g. Weiss_1988, Taillandier_2001, Whyte_2015, Seefried_2017, Del Angel_2020). These data indicate that the variant is very likely to be associated with disease. Experimental evidence obtained from multiple functional studies, demonstrated the variant causes a severe reduction in enzyme activity and affects its stability, transport and mineralisation ability (e.g. Weiss_1988, Fedde_1996, Di Mauro_2002, Zhu_2012, Del Angel_2020). A ClinVar submitter (evaluation after 2014) cites the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Aug 25, 2020
Natera, Inc.
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Childhood hypophosphatasia;C0268412:Infantile hypophosphatasia;C0268413:Adult hypophosphatasia Pathogenic:1
Jan 10, 2024
Fulgent Genetics, Fulgent Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Adult hypophosphatasia Pathogenic:1
Feb 14, 2024
Baylor Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.79
BayesDel_addAF
Pathogenic
0.52
D
BayesDel_noAF
Pathogenic
0.57
CADD
Pathogenic
26
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.97
D;.;.;D
Eigen
Pathogenic
0.78
Eigen_PC
Pathogenic
0.71
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.87
.;D;D;D
M_CAP
Pathogenic
0.54
D
MetaRNN
Pathogenic
0.99
D;D;D;D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
3.5
H;.;.;H
PrimateAI
Uncertain
0.71
T
PROVEAN
Uncertain
-3.5
D;D;D;D
REVEL
Pathogenic
0.94
Sift
Uncertain
0.0010
D;D;D;D
Sift4G
Uncertain
0.025
D;D;D;D
Polyphen
0.85
P;.;.;P
Vest4
0.99
MutPred
0.98
Gain of glycosylation at A179 (P = 0.0474);.;.;Gain of glycosylation at A179 (P = 0.0474);
MVP
0.99
MPC
0.91
ClinPred
0.99
D
GERP RS
5.3
Varity_R
0.82
gMVP
0.98

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

Publications

LitVar

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

Other links and lift over

dbSNP: rs121918000; hg19: chr1-21890596; COSMIC: COSV66379795; API