1-21564103-G-T

Variant names:

• chr1-21564103-G-T
• rs121918000
• NM_000478.6:c.535G>T

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000478.6(ALPL):​c.535G>T​(p.Ala179Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,742 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A179T) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ALPL NM_000478.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.55
• Publications: 16 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: 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

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 19 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000478.6
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-21564103-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 13662.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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALPL	NM_000478.6	MANE Select	c.535G>T	p.Ala179Ser	missense	Exon 6 of 12	NP_000469.3
	ALPL	NM_001369803.2		c.535G>T	p.Ala179Ser	missense	Exon 6 of 12	NP_001356732.1
	ALPL	NM_001369804.2		c.535G>T	p.Ala179Ser	missense	Exon 6 of 12	NP_001356733.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALPL	ENST00000374840.8	TSL:1 MANE Select	c.535G>T	p.Ala179Ser	missense	Exon 6 of 12	ENSP00000363973.3
	ALPL	ENST00000374832.5	TSL:2	c.535G>T	p.Ala179Ser	missense	Exon 6 of 12	ENSP00000363965.1
	ALPL	ENST00000540617.5	TSL:2	c.370G>T	p.Ala124Ser	missense	Exon 5 of 11	ENSP00000442672.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461742 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727192

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53306

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111990

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	D
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.89	D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		9.5
PrimateAI	Uncertain	0.68	T
PROVEAN	Uncertain	-2.6	D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.016	D
Sift4G	Uncertain	0.033	D
Polyphen		0.95	P
Vest4		0.87
MutPred		0.92		Gain of glycosylation at A179 (P = 0.0165)
MVP		0.99
MPC		1.2
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.53
gMVP		0.95
Mutation Taster		=22/78	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs121918000; hg19: chr1-21890596;