1-21554142-G-T

Variant names:

• chr1-21554142-G-T
• rs1553410728
• NM_000478.6:c.61G>T

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PVS1 PM2 PP3_Strong

The NM_000478.6(ALPL):​c.61G>T​(p.Glu21*) variant causes a stop gained, splice region change. The variant allele was found at a frequency of 0.000000684 in 1,461,476 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ALPL NM_000478.6 stop_gained, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.16
• Publications: 0 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

ENSG00000289715 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 561 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

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.61G>T	p.Glu21*	stop_gained splice_region	Exon 2 of 12	NP_000469.3
	ALPL	NM_001369803.2		c.61G>T	p.Glu21*	stop_gained splice_region	Exon 2 of 12	NP_001356732.1	P05186-1
	ALPL	NM_001369804.2		c.61G>T	p.Glu21*	stop_gained splice_region	Exon 2 of 12	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.61G>T	p.Glu21*	stop_gained splice_region	Exon 2 of 12	ENSP00000363973.3	P05186-1
	ALPL	ENST00000374832.5	TSL:2	c.61G>T	p.Glu21*	stop_gained splice_region	Exon 2 of 12	ENSP00000363965.1	P05186-1
	ALPL	ENST00000879459.1		c.61G>T	p.Gly21Trp	missense splice_region	Exon 1 of 10	ENSP00000549518.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461476 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727062

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44716

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39686

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53374

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111748

Other (OTH) AF: 0.00 AC: 0 AN: 60370

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	47
DANN	Uncertain	1.0
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Uncertain	0.87	D
M_CAP	Pathogenic	0.49	D
PhyloP100		4.2
Vest4		0.94
GERP RS		4.7
Mutation Taster		=10/190	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.96
SpliceAI score (max)		0.33		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.33		Position offset: 0

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

Other links and lift over

dbSNP: rs1553410728; hg19: chr1-21880635;