rs193922441

Positions:

• chr3-122261531-A-C
• chr3-122261531-A-G

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000388.4(CASR):​c.496A>C​(p.Ser166Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S166G) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.51

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 Pathogenic. Variant got 11 ACMG points.

• PM1: In a region_of_interest Ligand-binding 1 (LB1) (size 166) in uniprot entity CASR_HUMAN there are 70 pathogenic changes around while only 0 benign (100%) in NM_000388.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-122261531-A-G is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), CASR. . Gene score misZ: 3.1237 (greater than the threshold 3.09). Trascript score misZ: 4.8257 (greater than threshold 3.09). The gene has 114 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. GenCC has associacion of the gene with 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, 0.969

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CASR	NM_000388.4	c.496A>C	p.Ser166Arg	missense_variant	4/7	ENST00000639785.2	NP_000379.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CASR	ENST00000639785.2	c.496A>C	p.Ser166Arg	missense_variant	4/7	1	NM_000388.4	ENSP00000491584.2
CASR	ENST00000498619.4	c.496A>C	p.Ser166Arg	missense_variant	4/7	1		ENSP00000420194.1
CASR	ENST00000638421.1	c.496A>C	p.Ser166Arg	missense_variant	4/7	5		ENSP00000492190.1
CASR	ENST00000490131.7	c.496A>C	p.Ser166Arg	missense_variant	3/5	5		ENSP00000418685.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 15, 2021

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with CASR-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces serine with arginine at codon 166 of the CASR protein (p.Ser166Arg). The serine residue is highly conserved and there is a moderate physicochemical difference between serine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D;D;.;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	.;D;D;D
M_CAP	Pathogenic	0.55	D
MetaRNN	Pathogenic	0.97	D;D;D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	4.3	H;H;H;.
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-4.4	.;.;D;D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0030	.;.;D;D
Sift4G	Pathogenic	0.0010	.;.;D;D
Polyphen		1.0	D;D;.;.
Vest4		0.98, 0.98
MutPred		0.87		Gain of glycosylation at S169 (P = 0.0373);Gain of glycosylation at S169 (P = 0.0373);Gain of glycosylation at S169 (P = 0.0373);Gain of glycosylation at S169 (P = 0.0373);
MVP		0.98
MPC		1.7
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.98
gMVP		1.0

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-121980378;