NM_000388.4:c.1668G>T

Variant names:

• chr3-122282172-G-T
• rs186279271
• NM_000388.4:c.1668G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_000388.4(CASR):​c.1668G>T​(p.Glu556Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,614,050 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E556K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0780
• Publications: 1 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 4 ACMG points.

• PM1: In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain in NM_000388.4
• 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=0.2867871).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000388.4. 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
	CASR	NM_000388.4	MANE Select	c.1668G>T	p.Glu556Asp	missense	Exon 6 of 7	NP_000379.3
	CASR	NM_001178065.2		c.1698G>T	p.Glu566Asp	missense	Exon 6 of 7	NP_001171536.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CASR	ENST00000639785.2	TSL:1 MANE Select	c.1668G>T	p.Glu556Asp	missense	Exon 6 of 7	ENSP00000491584.2
	CASR	ENST00000498619.4	TSL:1	c.1698G>T	p.Glu566Asp	missense	Exon 6 of 7	ENSP00000420194.1
	CASR	ENST00000638421.1	TSL:5	c.1668G>T	p.Glu556Asp	missense	Exon 6 of 7	ENSP00000492190.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152194 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461856 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727232

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

American (AMR) AF: 0.00 AC: 0 AN: 44722

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

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111986

Other (OTH) AF: 0.0000166 AC: 1 AN: 60394

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152194 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74350

African (AFR) AF: 0.00 AC: 0 AN: 41452

American (AMR) AF: 0.000131 AC: 2 AN: 15284

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10618

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68036

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Nephrolithiasis/nephrocalcinosis Uncertain:1

Feb 12, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.E556D variant (also known as c.1668G>T), located in coding exon 5 of the CASR gene, results from a G to T substitution at nucleotide position 1668. The glutamic acid at codon 556 is replaced by aspartic acid, an amino acid with highly similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Benign	-0.0099	T
BayesDel_noAF	Benign	-0.25
CADD	Benign	14
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.58	D
Eigen	Benign	-0.58
Eigen_PC	Benign	-0.47
FATHMM_MKL	Benign	0.72	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.027	D
MetaRNN	Benign	0.29	T
MetaSVM	Benign	-0.36	T
MutationAssessor	Benign	1.3	L
PhyloP100		0.078
PrimateAI	Uncertain	0.63	T
PROVEAN	Benign	-1.7	N
REVEL	Uncertain	0.33
Sift	Benign	0.16	T
Sift4G	Benign	0.14	T
Polyphen		0.0050	B
Vest4		0.15
MutPred		0.48		Gain of sheet (P = 0.0344)
MVP		0.79
MPC		0.57
ClinPred		0.33	T
GERP RS		-0.36
Varity_R		0.38
gMVP		0.69
Mutation Taster		=70/30	polymorphism

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: rs186279271; hg19: chr3-122001019;