3-122261601-A-T

Variant names:

• chr3-122261601-A-T
• rs762998933
• NM_000388.4:c.566A>T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PP2 PP3_Moderate

The NM_000388.4(CASR):​c.566A>T​(p.Asn189Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.19

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• 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 epilepsy, autosomal dominant hypocalcemia, familial hypocalciuric hypercalcemia 1, epilepsy, idiopathic generalized, susceptibility to, 8, neonatal severe primary hyperparathyroidism, autosomal dominant hypocalcemia 1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.881

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CASR	NM_000388.4	c.566A>T	p.Asn189Ile	missense_variant	Exon 4 of 7	ENST00000639785.2	NP_000379.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CASR	ENST00000639785.2	c.566A>T	p.Asn189Ile	missense_variant	Exon 4 of 7	1	NM_000388.4	ENSP00000491584.2
CASR	ENST00000498619.4	c.566A>T	p.Asn189Ile	missense_variant	Exon 4 of 7	1		ENSP00000420194.1
CASR	ENST00000638421.1	c.566A>T	p.Asn189Ile	missense_variant	Exon 4 of 7	5		ENSP00000492190.1
CASR	ENST00000490131.7	c.566A>T	p.Asn189Ile	missense_variant	Exon 3 of 5	5		ENSP00000418685.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461862 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727234

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000719

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nephrolithiasis/nephrocalcinosis Uncertain:1

Jul 15, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.N189I variant (also known as c.566A>T), located in coding exon 3 of the CASR gene, results from an A to T substitution at nucleotide position 566. The asparagine at codon 189 is replaced by isoleucine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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

Aug 02, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces asparagine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 189 of the CASR protein (p.Asn189Ile). 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: 942321). 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 disruptive. 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	Pathogenic	0.62
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.79	D;D;.;.
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.95	.;D;D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.88	D;D;D;D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Uncertain	2.6	M;M;M;.
PrimateAI	Uncertain	0.72	T
PROVEAN	Uncertain	-4.1	.;.;D;D
REVEL	Pathogenic	0.77
Sift	Uncertain	0.0020	.;.;D;D
Sift4G	Uncertain	0.0050	.;.;D;D
Polyphen		0.98	D;D;.;.
Vest4		0.80, 0.80
MutPred		0.73		Loss of disorder (P = 0.0173);Loss of disorder (P = 0.0173);Loss of disorder (P = 0.0173);Loss of disorder (P = 0.0173);
MVP		0.90
MPC		1.6
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.92
gMVP		0.96

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

Publications

LitVar

Other links and lift over

dbSNP: rs762998933; hg19: chr3-121980448;