rs121912757

Variant names:

• chr17-44254616-C-G
• rs121912757
• NM_000342.4:c.1937G>C

Your query was ambiguous. Multiple possible variants found:

• chr17-44254616-C-G
• chr17-44254616-C-T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000342.4(SLC4A1):​c.1937G>C​(p.Arg646Pro) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,840 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R646Q) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SLC4A1 NM_000342.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.07
• Publications: 0 publications found

Genes affected

SLC4A1 (HGNC:11027): (solute carrier family 4 member 1 (Diego blood group)) The protein encoded by this gene is part of the anion exchanger (AE) family and is expressed in the erythrocyte plasma membrane, where it functions as a chloride/bicarbonate exchanger involved in carbon dioxide transport from tissues to lungs. The protein comprises two domains that are structurally and functionally distinct. The N-terminal 40kDa domain is located in the cytoplasm and acts as an attachment site for the red cell skeleton by binding ankyrin. The glycosylated C-terminal membrane-associated domain contains 12-14 membrane spanning segments and carries out the stilbene disulphonate-sensitive exchange transport of anions. The cytoplasmic tail at the extreme C-terminus of the membrane domain binds carbonic anhydrase II. The encoded protein associates with the red cell membrane protein glycophorin A and this association promotes the correct folding and translocation of the exchanger. This protein is predominantly dimeric but forms tetramers in the presence of ankyrin. Many mutations in this gene are known in man, and these mutations can lead to two types of disease: destabilization of red cell membrane leading to hereditary spherocytosis, and defective kidney acid secretion leading to distal renal tubular acidosis. Other mutations that do not give rise to disease result in novel blood group antigens, which form the Diego blood group system. Southeast Asian ovalocytosis (SAO, Melanesian ovalocytosis) results from the heterozygous presence of a deletion in the encoded protein and is common in areas where Plasmodium falciparum malaria is endemic. One null mutation in this gene is known, resulting in very severe anemia and nephrocalcinosis. [provided by RefSeq, Jul 2008]

SLC4A1 Gene-Disease associations (from GenCC):

• autosomal dominant distal renal tubular acidosis

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• hereditary spherocytosis type 4

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• renal tubular acidosis, distal, 4, with hemolytic anemia

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• southeast Asian ovalocytosis

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• dehydrated hereditary stomatocytosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary spherocytosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• cryohydrocytosis

  Inheritance: Unknown, AD Classification: SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.934

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SLC4A1	NM_000342.4	c.1937G>C	p.Arg646Pro	missense_variant	Exon 16 of 20	ENST00000262418.12	NP_000333.1
SLC4A1	XM_011525129.3	c.1847G>C	p.Arg616Pro	missense_variant	Exon 15 of 19		XP_011523431.1
SLC4A1	XM_005257593.6	c.1742G>C	p.Arg581Pro	missense_variant	Exon 14 of 18		XP_005257650.1
SLC4A1	XM_011525130.2	c.1937G>C	p.Arg646Pro	missense_variant	Exon 16 of 18		XP_011523432.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SLC4A1	ENST00000262418.12	c.1937G>C	p.Arg646Pro	missense_variant	Exon 16 of 20	1	NM_000342.4	ENSP00000262418.6
SLC4A1	ENST00000399246.3	c.839G>C	p.Arg280Pro	missense_variant	Exon 11 of 15	5		ENSP00000382190.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461840 Hom.: 0 Cov.: 35 AF XY: 0.00000138 AC XY: 1 AN XY: 727226

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: 26134

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

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: 8.99e-7 AC: 1 AN: 1111980

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

May 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 646 of the SLC4A1 protein (p.Arg646Pro). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SLC4A1-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SLC4A1 protein function with a positive predictive value of 80%. 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	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D;T
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.92	D;D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.93	D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Uncertain	2.4	M;.
PhyloP100		6.1
PrimateAI	Benign	0.45	T
PROVEAN	Pathogenic	-6.3	D;.
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D;.
Sift4G	Uncertain	0.0020	D;D
Polyphen		1.0	D;.
Vest4		0.83
MutPred		0.75		Loss of catalytic residue at R646 (P = 0.0054);.;
MVP		0.95
MPC		1.4
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.98
gMVP		0.98
Mutation Taster		=21/79	disease causing

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: rs121912757; hg19: chr17-42331984;