3-122275878-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_000388.4(CASR):c.1444T>C(p.Cys482Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 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. C482F) has been classified 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: 3.98

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.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, CASR
• BP4: Computational evidence support a benign effect (MetaRNN=0.31744078).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CASR	NM_000388.4	c.1444T>C	p.Cys482Arg	missense_variant	5/7	ENST00000639785.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CASR	ENST00000639785.2	c.1444T>C	p.Cys482Arg	missense_variant	5/7	1	NM_000388.4	P1
CASR	ENST00000498619.4	c.1444T>C	p.Cys482Arg	missense_variant	5/7	1
CASR	ENST00000638421.1	c.1444T>C	p.Cys482Arg	missense_variant	5/7	5		P1
CASR	ENST00000490131.7	c.1378-6235T>C		intron_variant		5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Nov 30, 2021

Variant summary: CASR c.1444T>C (p.Cys482Arg) results in a non-conservative amino acid change located in the Receptor, ligand binding region domain (IPR001828) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant was absent in 251452 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.1444T>C in individuals affected with Familial Hypocalciuric Hypercalcemia and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 25, 2023

This sequence change replaces cysteine, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 482 of the CASR protein (p.Cys482Arg). 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: 1328990). 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	0.10
BayesDel_addAF	Uncertain	0.049	T
BayesDel_noAF	Benign	-0.17
Cadd	Benign	23
Dann	Uncertain	0.98
DEOGEN2	Benign	0.32	T;T;.
Eigen	Benign	-0.20
Eigen_PC	Benign	0.083
FATHMM_MKL	Uncertain	0.92	D
M_CAP	Benign	0.042	D
MetaRNN	Benign	0.32	T;T;T
MetaSVM	Benign	-0.54	T
MutationAssessor	Benign	-1.5	N;N;N
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.50	T
Polyphen		0.11	B;B;.
Vest4		0.40
MutPred		0.45		Gain of disorder (P = 0.0144);Gain of disorder (P = 0.0144);Gain of disorder (P = 0.0144);
MVP		0.83
MPC		1.2
ClinPred		0.72	D
GERP RS		5.7
Varity_R		0.69
gMVP		0.63

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-121994725;