rs397514728

Positions:

• chr3-122261697-C-A
• chr3-122261697-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP2

The NM_000388.4(CASR):​c.662C>A​(p.Pro221Gln) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. P221S) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 6.14

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a helix (size 13) in uniprot entity CASR_HUMAN there are 15 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 chrnull-null-null-null is described in UniProt as null.
• 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). GenCC has associacion of gene with epilepsy, autosomal dominant hypocalcemia, familial hypocalciuric hypercalcemia 1, epilepsy, idiopathic generalized, susceptibility to, 8, neonatal severe primary hyperparathyroidism, autosomal dominant hypocalcemia 1.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CASR	NM_000388.4	c.662C>A	p.Pro221Gln	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.662C>A	p.Pro221Gln	missense_variant	4/7	1	NM_000388.4	ENSP00000491584	P1
CASR	ENST00000498619.4	c.662C>A	p.Pro221Gln	missense_variant	4/7	1		ENSP00000420194
CASR	ENST00000638421.1	c.662C>A	p.Pro221Gln	missense_variant	4/7	5		ENSP00000492190	P1
CASR	ENST00000490131.7	c.662C>A	p.Pro221Gln	missense_variant	3/5	5		ENSP00000418685

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial hypocalciuric hypercalcemia 1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jun 15, 2012

- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 27, 2022

This sequence change replaces proline, which is neutral and non-polar, with glutamine, which is neutral and polar, at codon 221 of the CASR protein (p.Pro221Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with hypocalciuric hypercalcemia (PMID: 17698911, 22422767). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 60668). 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. Experimental studies have shown that this missense change affects CASR function (PMID: 22422767). This variant disrupts the p.Pro221 amino acid residue in CASR. Other variant(s) that disrupt this residue have been observed in individuals with CASR-related conditions (PMID: 11136551, 12733714, 20119591, 21645025, 25137426), which suggests that this may be a clinically significant amino acid residue. 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	0.86
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Benign	21
DANN	Benign	0.96
DEOGEN2	Benign	0.34	T;T;.;.
Eigen	Benign	-0.011
Eigen_PC	Benign	0.052
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.92	.;D;D;D
M_CAP	Uncertain	0.21	D
MetaRNN	Uncertain	0.67	D;D;D;D
MetaSVM	Uncertain	-0.070	T
MutationAssessor	Benign	0.38	N;N;N;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Benign	-0.86	.;.;N;N
REVEL	Pathogenic	0.67
Sift	Benign	0.31	.;.;T;T
Sift4G	Benign	0.29	.;.;T;T
Polyphen		0.52	P;P;.;.
Vest4		0.74, 0.74
MutPred		0.62		Gain of glycosylation at Y218 (P = 0.0031);Gain of glycosylation at Y218 (P = 0.0031);Gain of glycosylation at Y218 (P = 0.0031);Gain of glycosylation at Y218 (P = 0.0031);
MVP		0.90
MPC		1.5
ClinPred		0.92	D
GERP RS		4.3
Varity_R		0.70
gMVP		0.76

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: rs397514728; hg19: chr3-121980544;