rs1553414147

Positions:

• chr1-21573802-A-C
• chr1-21573802-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 10P and 1B. PM2 PP5_Very_Strong BP4

The NM_000478.6(ALPL):​c.997+3A>C variant causes a splice donor region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: ALPL NM_000478.6 splice_donor_region, intron
• Scores: Splicing: ADA: 0.9295
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.06

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 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-21573802-A-C is Pathogenic according to our data. Variant chr1-21573802-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1472412.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-21573802-A-C is described in Lovd as [Pathogenic].
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.43). . Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALPL	NM_000478.6	c.997+3A>C		splice_donor_region_variant, intron_variant		ENST00000374840.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALPL	ENST00000374840.8	c.997+3A>C		splice_donor_region_variant, intron_variant		1	NM_000478.6	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Adult hypophosphatasia Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Feb 05, 2023

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Feb 02, 2021

This variant is not present in population databases (ExAC no frequency). This sequence change falls in intron 9 of the ALPL gene. It does not directly change the encoded amino acid sequence of the ALPL protein. It affects a nucleotide within the consensus splice site of the intron. This variant has been observed in individual(s) with autosomal recessive hypophosphatasia (PMID: 9781036, 10679946). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.43
CADD	Benign	19
DANN	Benign	0.83

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.93
dbscSNV1_RF	Pathogenic	0.79
SpliceAI score (max)		0.060		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: chr1-21900295;