1-21564217-G-A

Variant names:

• chr1-21564217-G-A
• rs749544042
• NM_000478.6:c.648+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1_Strong PS3 PP5_Very_Strong

The NM_000478.6(ALPL):​c.648+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000186 in 1,613,416 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001774692: Reduced enzymatic activity was noted in both compound heterozygous and heterozygous patients carrying the variant (example: Angel_2020, Krishnani_2021).".

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000019 (0 hom.)
• Consequence: ALPL NM_000478.6 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:15
• Conservation: PhyloP100: 9.47
• Publications: 4 publications found

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: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
• ALPL-related autosomal dominant hypophosphatasia

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• childhood hypophosphatasia

  Inheritance: AD, AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, Laboratory for Molecular Medicine, ClinGen
• ALPL-related autosomal recessive hypophosphatasia

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• hypophosphatasia

  Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health, G2P
• infantile hypophosphatasia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet, Labcorp Genetics (formerly Invitae)
• odontohypophosphatasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• perinatal lethal hypophosphatasia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.11174603 fraction of the gene. Cryptic splice site detected, with MaxEntScore 5.5, offset of 33, new splice context is: gggGTgagg. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV001774692: Reduced enzymatic activity was noted in both compound heterozygous and heterozygous patients carrying the variant (example: Angel_2020, Krishnani_2021).
• PP5: Variant 1-21564217-G-A is Pathogenic according to our data. Variant chr1-21564217-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 13678.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000478.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALPL	NM_000478.6	MANE Select	c.648+1G>A		splice_donor intron	N/A	NP_000469.3
	ALPL	NM_001369803.2		c.648+1G>A		splice_donor intron	N/A	NP_001356732.1	P05186-1
	ALPL	NM_001369804.2		c.648+1G>A		splice_donor intron	N/A	NP_001356733.1	P05186-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALPL	ENST00000374840.8	TSL:1 MANE Select	c.648+1G>A		splice_donor intron	N/A	ENSP00000363973.3	P05186-1
	ALPL	ENST00000374832.5	TSL:2	c.648+1G>A		splice_donor intron	N/A	ENSP00000363965.1	P05186-1
	ALPL	ENST00000879459.1		c.528+1G>A		splice_donor intron	N/A	ENSP00000549518.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152188 Hom.: 0 Cov.: 32

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: 0.0000147

Gnomad OTH AF: 0.000478

GnomAD2 exomes AF: 0.00000400 AC: 1 AN: 250046 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000192 AC: 28 AN: 1461228 Hom.: 0 Cov.: 32 AF XY: 0.0000110 AC XY: 8 AN XY: 726906

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.0000447 AC: 2 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52912

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.0000225 AC: 25 AN: 1111902

Other (OTH) AF: 0.0000166 AC: 1 AN: 60384

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152188 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74344

African (AFR) AF: 0.00 AC: 0 AN: 41442

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68022

Other (OTH) AF: 0.000478 AC: 1 AN: 2094

Alfa AF: 0.0000551 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.000164

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
5	-	-	Hypophosphatasia (5)
2	-	-	Infantile hypophosphatasia (2)
2	-	-	not provided (2)
1	-	-	Adult hypophosphatasia (1)
1	-	-	ALPL-related disorder (1)
1	-	-	Childhood hypophosphatasia;C0268412:Infantile hypophosphatasia;C0268413:Adult hypophosphatasia (1)
1	-	-	Childhood hypophosphatasia;C0268413:Adult hypophosphatasia (1)
1	-	-	Inborn genetic diseases (1)
1	-	-	Perinatal lethal hypophosphatasia (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		9.5
GERP RS		5.4
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.95		Position offset: -1

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

Other links and lift over

dbSNP: rs749544042; hg19: chr1-21890710;