rs1176923284

Positions:

• chr3-122284956-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM1 PP2 BS1_Supporting

The NM_000388.4(CASR):​c.3002A>C​(p.Gln1001Pro) variant causes a missense change. The variant allele was found at a frequency of 0.0000171 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. Q1001E) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.70

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 2 ACMG points.

• PM1: In a region_of_interest Disordered (size 20) in uniprot entity CASR_HUMAN there are 6 pathogenic changes around while only 2 benign (75%) in NM_000388.4
• 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.
• BS1: Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.0000171 (25/1461880) while in subpopulation EAS AF= 0.00063 (25/39700). AF 95% confidence interval is 0.000437. There are 0 homozygotes in gnomad4_exome. There are 10 alleles in male gnomad4_exome subpopulation. Median coverage is 70. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CASR	NM_000388.4	c.3002A>C	p.Gln1001Pro	missense_variant	7/7	ENST00000639785.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CASR	ENST00000639785.2	c.3002A>C	p.Gln1001Pro	missense_variant	7/7	1	NM_000388.4	P1
CASR	ENST00000498619.4	c.3032A>C	p.Gln1011Pro	missense_variant	7/7	1
CASR	ENST00000638421.1	c.3002A>C	p.Gln1001Pro	missense_variant	7/7	5		P1
CASR	ENST00000490131.7	c.2771A>C	p.Gln924Pro	missense_variant	5/5	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461880 Hom.: 0 Cov.: 70 AF XY: 0.0000138 AC XY: 10 AN XY: 727240

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000630

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nephrolithiasis/nephrocalcinosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 08, 2023

The p.Q1001P variant (also known as c.3002A>C), located in coding exon 6 of the CASR gene, results from an A to C substitution at nucleotide position 3002. The glutamine at codon 1001 is replaced by proline, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 13, 2023

This sequence change replaces glutamine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 1001 of the CASR protein (p.Gln1001Pro). 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: 532582). 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	0.076
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.33	T;T;.;.
Eigen	Uncertain	0.20
Eigen_PC	Uncertain	0.34
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.86	.;D;D;D
M_CAP	Uncertain	0.089	D
MetaRNN	Uncertain	0.45	T;T;T;T
MetaSVM	Uncertain	0.056	D
MutationAssessor	Benign	1.6	L;L;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-0.54	.;.;N;.
REVEL	Uncertain	0.48
Sift	Uncertain	0.0030	.;.;D;.
Sift4G	Uncertain	0.013	.;.;D;.
Polyphen		0.60	P;P;.;.
Vest4		0.60
MutPred		0.19		.;.;Loss of helix (P = 0.0068);.;
MVP		0.91
MPC		1.5
ClinPred		0.90	D
GERP RS		5.8
Varity_R		0.37
gMVP		0.48

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: rs1176923284; hg19: chr3-122003803;