rs886041154

Variant names:

• chr3-122254353-C-T
• rs886041154
• NM_000388.4:c.164C>T

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PS1 PM1 PM2 PP2 PP3_Moderate PP5_Very_Strong

The NM_000388.4(CASR):​c.164C>T​(p.Pro55Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,862 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 nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P55S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 7.82
• Publications: 13 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: Pathogenic. The variant received 19 ACMG points.

• PS1: Transcript NM_000388.4 (CASR) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 22 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.88
• PP5: Variant 3-122254353-C-T is Pathogenic according to our data. Variant chr3-122254353-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 279731.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.164C>T	p.Pro55Leu	missense	Exon 2 of 7	NP_000379.3
	CASR	NM_001178065.2		c.164C>T	p.Pro55Leu	missense	Exon 2 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.164C>T	p.Pro55Leu	missense	Exon 2 of 7	ENSP00000491584.2
	CASR	ENST00000498619.4	TSL:1	c.164C>T	p.Pro55Leu	missense	Exon 2 of 7	ENSP00000420194.1
	CASR	ENST00000638421.1	TSL:5	c.164C>T	p.Pro55Leu	missense	Exon 2 of 7	ENSP00000492190.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461862 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727230

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

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

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

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111994

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Nov 16, 2022

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has been identified in multiple unrelated individuals with autosomal dominant hypocalciuric hypercalcemia and segregates with disease in multiple families. 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. (PMID: 8878438, 10468915, 11763315, 19759318, 8636323, 8675635).

May 23, 2018

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The P55L pathogenic variant in the CASR gene has been reported previously in association with familial hypocalciuric hypercalcemia (Pearce et al., 1995; Hannan et al., 2012). This variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Functional studies demonstrate that this substitution reduces calcium ion binding affinity of the extracellular domain of the CASR protein and leads to abnormal moderation of calcium homeostasis (Pearce et al., 1996; White et al., 2009; Lu et al., 2009). We interpret P55L as a pathogenic variant.

Sep 19, 2024

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PP1, PP2, PP3, PM2, PS3, PS4_moderate

Nephrolithiasis/nephrocalcinosis Pathogenic:1

Oct 24, 2022

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.P55L pathogenic mutation (also known as c.164C>T), located in coding exon 1 of the CASR gene, results from a C to T substitution at nucleotide position 164. The proline at codon 55 is replaced by leucine, an amino acid with similar properties. This mutation has been reported in multiple unrelated individuals and families with familial hypocalciuric hypercalcemia (Pearce SH et al. J Clin Invest, 1995 Dec;96:2683-92; Heath H et al. J Clin Endocrinol Metab, 1996 Apr;81:1312-7; Cetani F et al. Clin Endocrinol (Oxf), 2003 Feb;58:199-206; Speer G et al. Exp Clin Endocrinol Diabetes, 2003 Dec;111:486-90; Guarnieri V et al. J Clin Endocrinol Metab, 2010 Apr;95:1819-29; Hannan FM et al. Hum Mol Genet, 2012 Jun;21:2768-78). In vitro studies showed that P55L reduces the ability of the calcium-sensing receptor to sense extracellular calcium (Pearce SH et al. J Clin Invest, 1996 Oct;98:1860-6; Heath H et al. J Clin Endocrinol Metab, 1996 Apr;81:1312-7; Lu JY et al. J Pharmacol Exp Ther, 2009 Dec;331:775-86). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation.

Familial hypocalciuric hypercalcemia 1 Pathogenic:1

Mar 08, 2024

Molecular Genetics Laboratory, Biobizkaia Health Research Institute

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

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

Dec 08, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 55 of the CASR protein (p.Pro55Leu). 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: 8675635, 11763315, 12580936, 20164288, 22422767, 24947037). It has also been observed to segregate with disease in related individuals. Invitae Evidence Modeling of clinical and family history, age, sex, and reported ancestry of multiple individuals with this CASR variant has been performed. This variant is expected to be pathogenic with a positive predictive value of at least 99%. This is a validated machine learning model that incorporates the clinical features of 606,512 individuals referred to our laboratory for CASR testing. ClinVar contains an entry for this variant (Variation ID: 279731). 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: 8878438, 19389809, 19759318). For these reasons, this variant has been classified as Pathogenic.

Familial hypocalciuric hypercalcemia Pathogenic:1

Nov 15, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CASR c.164C>T (p.Pro55Leu) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 250952 control chromosomes. c.164C>T has been widely reported in the literature in multiple individuals affected with Familial Hypocalciuric Hypercalcemia (example, Pearce_1995, Sumida_2022). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in reduced responsiveness of the calcium receptor to ionic calcium levels consistent with a loss of function mechanism of disease (example, Pearce_1996). Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.88	D
MetaSVM	Pathogenic	0.81	D
MutationAssessor	Pathogenic	3.5	H
PhyloP100		7.8
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-8.2	D
REVEL	Pathogenic	0.86
Sift	Uncertain	0.018	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.46		Gain of glycosylation at S57 (P = 0.0158)
MVP		0.97
MPC		1.6
ClinPred		1.0	D
GERP RS		5.4
PromoterAI		-0.026	Neutral
Varity_R		0.81
gMVP		0.91
Mutation Taster		=6/94	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs886041154; hg19: chr3-121973200;