3-122284611-G-C

Position:

• chr3-122284611-G-C

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP2 PP3 PP5_Very_Strong

The NM_000388.4(CASR):​c.2657G>C​(p.Arg886Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,762 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R886G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.53

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 16 ACMG points.

• PM1: In a region_of_interest Interaction with RNF19A (size 20) in uniprot entity CASR_HUMAN there are 10 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 chr3-122284610-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 935768.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, CASR
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.759
• PP5: Variant 3-122284611-G-C is Pathogenic according to our data. Variant chr3-122284611-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 379932.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr3-122284611-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CASR	NM_000388.4	c.2657G>C	p.Arg886Pro	missense_variant	7/7	ENST00000639785.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CASR	ENST00000639785.2	c.2657G>C	p.Arg886Pro	missense_variant	7/7	1	NM_000388.4	P1
CASR	ENST00000498619.4	c.2687G>C	p.Arg896Pro	missense_variant	7/7	1
CASR	ENST00000638421.1	c.2657G>C	p.Arg886Pro	missense_variant	7/7	5		P1
CASR	ENST00000490131.7	c.2426G>C	p.Arg809Pro	missense_variant	5/5	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461762 Hom.: 0 Cov.: 70 AF XY: 0.00000138 AC XY: 1 AN XY: 727200

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Apr 19, 2022	This variant appears to segregate with disease in at least one family. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). Assessment of experimental evidence suggests this variant results in abnormal protein function. This variant was shown to impair receptor function (PMID: 20798521). -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 19, 2018	The R886P missense variant in the CASR gene has been previously reported to segregate with disease in at least one family with familial hypocalciuric hyercalcemia (Simmonds et al., 2002). A functional study of the R886P variant has shown that it results in increased expression with reduced levels of calcium-stimulated ERK 1/2 phosphorylation (Stepanchick et al., 2010). This variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). R886P is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position where amino acids with similar properties to arginine are tolerated across species. A missense variant at the same codon (R886W) has been reported in association with hypocalciuric hypercalcaemia, supporting the functional importance of this region of the protein (Nissen et al., 2007). Based on currently available evidence, we consider R886P to be pathogenic. -

Familial hypocalciuric hypercalcemia 1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Jan 01, 2002

- -

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

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 11, 2023

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 886 of the CASR protein (p.Arg886Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with familial hypocalciuric hypercalcemia (PMID: 11807402). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 379932). 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. Experimental studies have shown that this missense change affects CASR function (PMID: 20798521). This variant disrupts the p.Arg886 amino acid residue in CASR. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17698911). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	T;T;.;.
Eigen	Uncertain	0.61
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.76	D;D;D;D
MetaSVM	Uncertain	0.40	D
MutationAssessor	Benign	1.8	L;L;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.53	T
Polyphen		0.99	D;D;.;.
Vest4		0.79
MutPred		0.53		.;.;Loss of MoRF binding (P = 0.0031);.;
MVP		0.97
MPC		1.7
ClinPred		0.98	D
GERP RS		5.9
Varity_R		0.55
gMVP		0.80

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: rs1057520791; hg19: chr3-122003458;