rs1553768128

Variant names:

• chr3-122276015-A-T
• rs1553768128
• NM_000388.4:c.1581A>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_000388.4(CASR):​c.1581A>T​(p.Lys527Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.90
• Publications: 0 publications found

Genes affected

CASR (HGNC:1514): (calcium sensing receptor) The protein encoded by this gene is a plasma membrane G protein-coupled receptor that senses small changes in circulating calcium concentration. The encoded protein couples this information to intracellular signaling pathways that modify parathyroid hormone secretion or renal cation handling, and thus this protein plays an essential role in maintaining mineral ion homeostasis. Mutations in this gene are a cause of familial hypocalciuric hypercalcemia, neonatal severe hyperparathyroidism, and autosomal dominant hypocalcemia. [provided by RefSeq, Aug 2017]

CASR Gene-Disease associations (from GenCC):

• autosomal dominant hypocalcemia 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Illumina, ClinGen, Labcorp Genetics (formerly Invitae)
• familial hypocalciuric hypercalcemia 1

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Illumina, Orphanet, Genomics England PanelApp
• neonatal severe primary hyperparathyroidism

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Labcorp Genetics (formerly Invitae)
• autosomal dominant hypocalcemia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• epilepsy, idiopathic generalized, susceptibility to, 8

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• epilepsy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the CASR gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 114 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. Gene score misZ: 3.1237 (above the threshold of 3.09). Trascript score misZ: 4.8257 (above the threshold of 3.09). GenCC associations: The gene is linked to neonatal severe primary hyperparathyroidism, autosomal dominant hypocalcemia 1, familial hypocalciuric hypercalcemia 1, epilepsy, autosomal dominant hypocalcemia, epilepsy, idiopathic generalized, susceptibility to, 8.
• BP4: Computational evidence support a benign effect (MetaRNN=0.4178658).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CASR	NM_000388.4	c.1581A>T	p.Lys527Asn	missense_variant	Exon 5 of 7	ENST00000639785.2	NP_000379.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CASR	ENST00000639785.2	c.1581A>T	p.Lys527Asn	missense_variant	Exon 5 of 7	1	NM_000388.4	ENSP00000491584.2
CASR	ENST00000498619.4	c.1581A>T	p.Lys527Asn	missense_variant	Exon 5 of 7	1		ENSP00000420194.1
CASR	ENST00000638421.1	c.1581A>T	p.Lys527Asn	missense_variant	Exon 5 of 7	5		ENSP00000492190.1
CASR	ENST00000490131.7	c.1378-6098A>T		intron_variant	Intron 3 of 4	5		ENSP00000418685.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460872 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726822

African (AFR) AF: 0.00 AC: 0 AN: 33442

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86230

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

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

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111126

Other (OTH) AF: 0.00 AC: 0 AN: 60350

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal dominant hypocalcemia 1;C1809471:Familial hypocalciuric hypercalcemia Uncertain:1

Nov 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 527 of the CASR protein (p.Lys527Asn). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CASR-related conditions. ClinVar contains an entry for this variant (Variation ID: 532585). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.065	T
BayesDel_noAF	Benign	-0.14
CADD	Benign	18
DANN	Uncertain	1.0
DEOGEN2	Benign	0.35	T;T;.
Eigen	Benign	0.050
Eigen_PC	Benign	0.027
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Benign	0.82	.;T;T
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.42	T;T;T
MetaSVM	Uncertain	-0.13	T
MutationAssessor	Benign	1.9	L;L;L
PhyloP100		1.9
PrimateAI	Uncertain	0.56	T
PROVEAN	Benign	-1.5	.;.;N
REVEL	Uncertain	0.56
Sift	Benign	0.11	.;.;T
Sift4G	Benign	0.34	.;.;T
Polyphen		1.0	D;D;.
Vest4		0.91
MutPred		0.41		Loss of ubiquitination at K527 (P = 0.0134);Loss of ubiquitination at K527 (P = 0.0134);Loss of ubiquitination at K527 (P = 0.0134);
MVP		0.91
MPC		0.95
ClinPred		0.78	D
GERP RS		1.7
Varity_R		0.43
gMVP		0.80
Mutation Taster		=25/75	disease causing

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

Other links and lift over

dbSNP: rs1553768128; hg19: chr3-121994862;