rs150799088

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1PM5PP2BP4

The NM_000478.6(ALPL):​c.1349G>A​(p.Arg450His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000057 in 1,613,154 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R450C) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000060 ( 1 hom. )

Consequence

ALPL
NM_000478.6 missense

Scores

3
6
10

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:9

Conservation

PhyloP100: 0.746

Publications

5 publications found
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 Gene-Disease associations (from GenCC):
  • adult hypophosphatasia
    Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, PanelApp Australia, Labcorp Genetics (formerly Invitae), Orphanet
  • childhood hypophosphatasia
    Inheritance: AR, AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, ClinGen, Orphanet
  • hypophosphatasia
    Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health, G2P
  • infantile hypophosphatasia
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Labcorp Genetics (formerly Invitae), PanelApp Australia
  • odontohypophosphatasia
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • perinatal lethal hypophosphatasia
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1
In a hotspot region, there are 21 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 chr1-21577421-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 971527.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 220 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. Gene score misZ: 1.2672 (below the threshold of 3.09). Trascript score misZ: 1.9021 (below the threshold of 3.09). GenCC associations: The gene is linked to adult hypophosphatasia, infantile hypophosphatasia, odontohypophosphatasia, childhood hypophosphatasia, hypophosphatasia, perinatal lethal hypophosphatasia.
BP4
Computational evidence support a benign effect (MetaRNN=0.35421142).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
ALPLNM_000478.6 linkc.1349G>A p.Arg450His missense_variant Exon 12 of 12 ENST00000374840.8 NP_000469.3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ALPLENST00000374840.8 linkc.1349G>A p.Arg450His missense_variant Exon 12 of 12 1 NM_000478.6 ENSP00000363973.3

Frequencies

GnomAD3 genomes
AF:
0.0000263
AC:
4
AN:
152208
Hom.:
0
Cov.:
32
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:
0.000413
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.000478
GnomAD2 exomes
AF:
0.0000772
AC:
19
AN:
246148
AF XY:
0.0000448
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000545
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000602
AC:
88
AN:
1460828
Hom.:
1
Cov.:
33
AF XY:
0.0000633
AC XY:
46
AN XY:
726772
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33476
American (AMR)
AF:
0.00
AC:
0
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26124
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39694
South Asian (SAS)
AF:
0.000383
AC:
33
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52478
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000468
AC:
52
AN:
1111932
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60382
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.499
Heterozygous variant carriers
0
6
12
18
24
30
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
4
8
12
16
20
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000263
AC:
4
AN:
152326
Hom.:
0
Cov.:
32
AF XY:
0.0000403
AC XY:
3
AN XY:
74480
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41574
American (AMR)
AF:
0.00
AC:
0
AN:
15306
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5184
South Asian (SAS)
AF:
0.000414
AC:
2
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10618
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68016
Other (OTH)
AF:
0.000473
AC:
1
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.438
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000132
Hom.:
1
Bravo
AF:
0.0000264
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000117
AC:
1
ExAC
AF:
0.0000825
AC:
10
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:9
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Uncertain:3
Dec 11, 2017
ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The ALPL: p.Arg450His variant (also reported as R433H; rs150799088) has been previously reported in a patient with odontohypophosphatasia (Taillandier 2000). The patient described in Taillandier et al (2000) also carried a second rare ALPL variant, but further inheritance information, including the phase of the two ALPL variants was not provided. Function studies of the p.Arg450His variant in cell culture could not identify an enzymatic defect (Nasu 2006), although a different variant in the same codon, p.Arg450Cys, lead to a severe disruption in enzyme function (Nasu 2006). However, the p.Arg450Cys variant has been identified as a homozygote in individuals with severe hypophosphatasia (Mornet 1988), and the function defects described in Nasu et al (2006) are likely attributable to the substituted cysteine residue. Furthermore, the p.Arg450His variant is listed in the Genome Aggregation Database (gnomAD) browser with a frequency in South Asian populations of 0.04% (identified in 13 out of 30,690 chromosomes, including 1 homozygote). Therefore, based on the available information, the clinical significance of the p.Arg450His variant cannot be determined with certainty. -

May 25, 2022
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Identified in a patient with reduced alkaline phosphatase activity who also harbored a second variant (phase unknown) in published literature (Taillandier et al., 2000); Published functional studies demonstrate that this variant does not impact enzyme activity levels (Del Angel et al., 2020; Nasu et al., 2006); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 17212778, 16769381, 32160374, 23791648, 10679946, 25023282) -

Nov 05, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 450 of the ALPL protein (p.Arg450His). This variant is present in population databases (rs150799088, gnomAD 0.04%). This missense change has been observed in individual(s) with hypophosphatasia (PMID: 10679946). This variant is also known as R433H. ClinVar contains an entry for this variant (Variation ID: 429390). 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 does not substantially affect ALPL function (PMID: 17212778, 32160374). This variant disrupts the p.Arg450 amino acid residue in ALPL. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9781036, 17212778, 25731960, 29159075). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Childhood hypophosphatasia;C0268412:Infantile hypophosphatasia;C0268413:Adult hypophosphatasia Uncertain:2
Jun 01, 2024
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 21, 2022
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:research

- -

Infantile hypophosphatasia Uncertain:2
Nov 14, 2017
Counsyl
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Jun 10, 2021
Genome-Nilou Lab
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:1
Nov 29, 2022
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: ALPL c.1349G>A (p.Arg450His) 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 7.7e-05 in 246148 control chromosomes in the gnomAD database, including 1 homozygote. This frequency is not significantly higher than estimated for a pathogenic variant in ALPL causing Hypophosphatasia (7.7e-05 vs 0.0035), allowing no conclusion about variant significance. c.1349G>A has been reported in the literature as a compound heterozygous genotype in at-least one individual affected with Odontoid Hypophosphatasia (example Taillandier_2000 cited in Del Angel_2020). These data do not allow any conclusion about variant significance. At least two publications report experimental evidence evaluating an impact on protein function (example, Nasu_2006 and Del Angel_2020). These results showed no damaging effect of this variant on ALPL activity in-vitro. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Hypophosphatasia Uncertain:1
Sep 16, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.099
BayesDel_addAF
Uncertain
0.043
T
BayesDel_noAF
Pathogenic
0.15
CADD
Uncertain
25
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.63
D;.;.;D
Eigen
Benign
0.068
Eigen_PC
Benign
0.064
FATHMM_MKL
Benign
0.35
N
LIST_S2
Uncertain
0.97
.;D;D;D
M_CAP
Pathogenic
0.63
D
MetaRNN
Benign
0.35
T;T;T;T
MetaSVM
Pathogenic
0.82
D
MutationAssessor
Benign
2.0
M;.;.;M
PhyloP100
0.75
PrimateAI
Uncertain
0.56
T
PROVEAN
Benign
-0.59
N;N;N;N
REVEL
Uncertain
0.62
Sift
Benign
0.21
T;T;T;T
Sift4G
Benign
0.13
T;T;T;T
Polyphen
0.98
D;.;.;D
Vest4
0.53
MVP
0.95
MPC
1.3
ClinPred
0.14
T
GERP RS
4.6
Varity_R
0.083
gMVP
0.70
Mutation Taster
=78/22
polymorphism

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

Other links and lift over

dbSNP: rs150799088; hg19: chr1-21903915; COSMIC: COSV66376605; API