1-21554122-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Moderate PP5_Moderate

The NM_000478.6(ALPL):c.41T>C(p.Leu14Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L14F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: ALPL NM_000478.6 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.33

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_000478.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.874
• PP5: Variant 1-21554122-T-C is Pathogenic according to our data. Variant chr1-21554122-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1334788.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALPL	NM_000478.6	c.41T>C	p.Leu14Pro	missense_variant	2/12	ENST00000374840.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALPL	ENST00000374840.8	c.41T>C	p.Leu14Pro	missense_variant	2/12	1	NM_000478.6	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypophosphatasia Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

JKU Lab, Dept of Paediatrics, Johannes Kepler University

Dec 16, 2021

This variant is absent from large population studies. Functional studies performed at the JKU Hoegler lab showed reduced ALPL activity (https://alplmutationdatabase.jku.at/table/). ACMG Criteria used for classification: PS3_Mod, PM2_Sup, PM3_Sup, PP2_Sup, PP3_Sup, PP4_Sup. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Benign	0.31	T;T
Eigen	Uncertain	0.41
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.78	D
M_CAP	Pathogenic	0.43	D
MetaRNN	Pathogenic	0.87	D;D
MetaSVM	Uncertain	0.73	D
MutationAssessor	Uncertain	2.2	M;M
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-1.6	N;N
REVEL	Pathogenic	0.75
Sift	Benign	0.073	T;T
Sift4G	Benign	0.12	T;T
Polyphen		0.94	P;P
Vest4		0.78
MutPred		0.67		Loss of helix (P = 0.0093);Loss of helix (P = 0.0093);
MVP		0.99
MPC		1.2
ClinPred		0.92	D
GERP RS		4.7
Varity_R		0.61
gMVP		0.85

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-21880615;