chr3-122284018-C-G

Variant names:

• chr3-122284018-C-G
• rs150869744
• NM_000388.4:c.2064C>G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000388.4(CASR):​c.2064C>G​(p.Phe688Leu) variant causes a missense change involving the alteration of a non-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 (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -0.329

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 9 ACMG points.

• PM1: In a helix (size 15) in uniprot entity CASR_HUMAN there are 8 pathogenic changes around while only 0 benign (100%) 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 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, 0.971

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CASR	NM_000388.4	c.2064C>G	p.Phe688Leu	missense_variant	Exon 7 of 7	ENST00000639785.2	NP_000379.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CASR	ENST00000639785.2	c.2064C>G	p.Phe688Leu	missense_variant	Exon 7 of 7	1	NM_000388.4	ENSP00000491584.2
CASR	ENST00000498619.4	c.2094C>G	p.Phe698Leu	missense_variant	Exon 7 of 7	1		ENSP00000420194.1
CASR	ENST00000638421.1	c.2064C>G	p.Phe688Leu	missense_variant	Exon 7 of 7	5		ENSP00000492190.1
CASR	ENST00000490131.7	c.1833C>G	p.Phe611Leu	missense_variant	Exon 5 of 5	5		ENSP00000418685.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nephrolithiasis/nephrocalcinosis Uncertain:1

Feb 16, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.F688L variant (also known as c.2064C>G), located in coding exon 6 of the CASR gene, results from a C to G substitution at nucleotide position 2064. The phenylalanine at codon 688 is replaced by leucine, an amino acid with highly similar properties. This amino acid position is conserved. 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

Feb 27, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). This sequence change replaces phenylalanine with leucine at codon 688 of the CASR protein (p.Phe688Leu). The phenylalanine residue is highly conserved and there is a small physicochemical difference between phenylalanine and leucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with CASR-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D;D;.;.
Eigen	Benign	0.072
Eigen_PC	Benign	-0.15
FATHMM_MKL	Benign	0.33	N
LIST_S2	Pathogenic	0.98	.;D;D;D
M_CAP	Uncertain	0.24	D
MetaRNN	Pathogenic	0.97	D;D;D;D
MetaSVM	Uncertain	0.76	D
MutationAssessor	Uncertain	2.5	M;M;.;.
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-5.8	.;.;D;.
REVEL	Pathogenic	0.81
Sift	Pathogenic	0.0	.;.;D;.
Sift4G	Pathogenic	0.0	.;.;D;.
Polyphen		1.0	D;D;.;.
Vest4		0.97
MutPred		0.93		.;.;Loss of sheet (P = 0.1907);.;
MVP		0.96
MPC		1.7
ClinPred		1.0	D
GERP RS		-3.9
Varity_R		0.94
gMVP		0.92

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: rs150869744; hg19: chr3-122002865;