3-122284592-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM1 PP2 BP4

The NM_000388.4(CASR):c.2638G>T(p.Ala880Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000041 in 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. A880P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: CASR NM_000388.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 6.44

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 hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000388.4
• PP2: Missense variant where missense usually causes diseases, CASR
• BP4: Computational evidence support a benign effect (MetaRNN=0.41481364).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CASR	NM_000388.4	c.2638G>T	p.Ala880Ser	missense_variant	7/7	ENST00000639785.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CASR	ENST00000639785.2	c.2638G>T	p.Ala880Ser	missense_variant	7/7	1	NM_000388.4	P1
CASR	ENST00000498619.4	c.2668G>T	p.Ala890Ser	missense_variant	7/7	1
CASR	ENST00000638421.1	c.2638G>T	p.Ala880Ser	missense_variant	7/7	5		P1
CASR	ENST00000490131.7	c.2407G>T	p.Ala803Ser	missense_variant	5/5	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251114 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135814

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000145

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461822 Hom.: 0 Cov.: 70 AF XY: 0.00000550 AC XY: 4 AN XY: 727222

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000134

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Nephrolithiasis/nephrocalcinosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 26, 2021

The p.A880S variant (also known as c.2638G>T), located in coding exon 6 of the CASR gene, results from a G to T substitution at nucleotide position 2638. The alanine at codon 880 is replaced by serine, an amino acid with similar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. 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

Invitae

Jan 13, 2024

This sequence change replaces alanine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 880 of the CASR protein (p.Ala880Ser). This variant is present in population databases (rs763865303, gnomAD 0.01%). 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: 653245). 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. 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. -

Autosomal dominant hypocalcemia 1;C0342637:Familial hypocalciuric hypercalcemia 1;C1832615:Neonatal severe primary hyperparathyroidism;C2752062:Epilepsy, idiopathic generalized, susceptibility to, 8 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Aug 03, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.016	T
BayesDel_noAF	Uncertain	0.040
Cadd	Benign	21
Dann	Uncertain	0.99
DEOGEN2	Benign	0.27	T;T;.;.
Eigen	Uncertain	0.21
Eigen_PC	Uncertain	0.36
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Uncertain	0.092	D
MetaRNN	Benign	0.41	T;T;T;T
MetaSVM	Uncertain	-0.15	T
MutationAssessor	Benign	1.8	L;L;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.83	D
Polyphen		0.82	P;P;.;.
Vest4		0.25
MutPred		0.35		.;.;Gain of disorder (P = 0.0483);.;
MVP		0.92
MPC		0.79
ClinPred		0.25	T
GERP RS		5.9
Varity_R		0.21
gMVP		0.70

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: rs763865303; hg19: chr3-122003439;