7-107710135-A-T

Variant names:

• chr7-107710135-A-T
• rs757820624
• NM_000441.2:c.2171A>T

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000441.2(SLC26A4):​c.2171A>T​(p.Asp724Val) variant causes a missense change. 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D724N) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SLC26A4 NM_000441.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.10
• Publications: 1 publications found

Genes affected

SLC26A4 (HGNC:8818): (solute carrier family 26 member 4) Mutations in this gene are associated with Pendred syndrome, the most common form of syndromic deafness, an autosomal-recessive disease. It is highly homologous to the SLC26A3 gene; they have similar genomic structures and this gene is located 3' of the SLC26A3 gene. The encoded protein has homology to sulfate transporters. [provided by RefSeq, Jul 2008]

SLC26A4 Gene-Disease associations (from GenCC):

• autosomal recessive nonsyndromic hearing loss 4

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• Pendred syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
• athyreosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• thyroid hypoplasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hearing loss, autosomal recessive

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 3 uncertain in NM_000441.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-107710134-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 553188.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 167 curated pathogenic missense variants (we use a threshold of 10). The gene has 19 curated benign missense variants. Trascript score misZ: -1.7621 (below the threshold of 3.09). GenCC associations: The gene is linked to autosomal recessive nonsyndromic hearing loss 4, Pendred syndrome, athyreosis, thyroid hypoplasia, hearing loss, autosomal recessive.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SLC26A4	NM_000441.2	c.2171A>T	p.Asp724Val	missense_variant	Exon 19 of 21	ENST00000644269.2	NP_000432.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SLC26A4	ENST00000644269.2	c.2171A>T	p.Asp724Val	missense_variant	Exon 19 of 21		NM_000441.2	ENSP00000494017.1
SLC26A4	ENST00000644846.1	n.*73A>T		non_coding_transcript_exon_variant	Exon 8 of 10			ENSP00000494344.1
SLC26A4	ENST00000644846.1	n.*73A>T		3_prime_UTR_variant	Exon 8 of 10			ENSP00000494344.1
SLC26A4	ENST00000492030.2	n.377-20A>T		intron_variant	Intron 3 of 5	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jan 17, 2023

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SLC26A4 c.2171A>T (p.Asp724Val) results in a non-conservative amino acid change located in the STAS domain (IPR002645) of 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 251296 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.2171A>T has been reported in the literature as a presumed compound heterozygous genotype in at-least one comprehensively genotyped individual of African (Nigerian) descent in a large multiethnic cohort of GJB2 mutation-negative deaf probands (example, Yan_2016 cited in Rudman_2017). A confirmed clinical diagnosis of Pendred syndrome in this reported proband was not specified. These data do not allow any conclusion about variant significance in context of Pendred syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Although a different variant, NM_000441.2(SLC26A4):c.2171A>G (p.Asp724Gly) has been reported with concordant Pathogenic/Likely Pathogenic classifications in the ClinVar database, supporting a possible functional relevance of this residue towards SLC26A4 protein function. Based on the evidence outlined above, until additional clinical cases and/or a functional study are identified, the variant was classified as VUS-possibly pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.78	D;D
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.0	.;D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Uncertain	2.9	M;M
PhyloP100		7.1
PrimateAI	Benign	0.45	T
PROVEAN	Pathogenic	-8.0	D;.
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;.
Vest4		0.91
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.98
gMVP		0.91
Mutation Taster		=3/97	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: rs757820624; hg19: chr7-107350580;