14-60648804-T-C

Position:

• chr14-60648804-T-C

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_005982.4(SIX1):​c.386A>G​(p.Tyr129Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,880 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 Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SIX1 NM_005982.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:10 O:1
• Conservation: PhyloP100: 8.01

Genes affected

SIX1 (HGNC:10887): (SIX homeobox 1) The protein encoded by this gene is a homeobox protein that is similar to the Drosophila 'sine oculis' gene product. This gene is found in a cluster of related genes on chromosome 14 and is thought to be involved in limb development. Defects in this gene are a cause of autosomal dominant deafness type 23 (DFNA23) and branchiootic syndrome type 3 (BOS3). [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a DNA_binding_region Homeobox (size 59) in uniprot entity SIX1_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_005982.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 14-60648804-T-C is Pathogenic according to our data. Variant chr14-60648804-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 8308.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr14-60648804-T-C is described in Lovd as [Pathogenic]. Variant chr14-60648804-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SIX1	NM_005982.4	c.386A>G	p.Tyr129Cys	missense_variant	1/2	ENST00000645694.3	NP_005973.1
SIX1	XM_017021602.3	c.386A>G	p.Tyr129Cys	missense_variant	1/2		XP_016877091.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SIX1	ENST00000645694.3	c.386A>G	p.Tyr129Cys	missense_variant	1/2		NM_005982.4	ENSP00000494686	P1
SIX1	ENST00000554986.2	c.42-2227A>G		intron_variant		3		ENSP00000452700
SIX1	ENST00000553535.2	n.249-2227A>G		intron_variant, non_coding_transcript_variant		3
SIX1	ENST00000555955.3	n.1198-2227A>G		intron_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251416 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135904

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

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: 0.00000137 AC: 2 AN: 1461880 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727242

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 29, 2023	Observed in multiple unrelated patients from different ethnic backgrounds with clinical features of branchiootorenal spectrum disorder (Ruf et al., 2004; Ito et al., 2006; Krug et al., 2011; Noguchi et al., 2011); Published functional studies demonstrate a damaging effect with deficient DNA binding (Ruf et al., 2004; Patrick et al., 2009); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 15141091, 19497856, 34208995, 31980437, 31595699, 16652090, 21280147, 21254961, 25326635) -
Pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

Branchiootic syndrome 3 Pathogenic:2 Other:1

Pathogenic, no assertion criteria provided	literature only	OMIM	May 25, 2004	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jul 15, 2022	Variant summary: SIX1 c.386A>G (p.Tyr129Cys) results in a non-conservative amino acid change located in the Homeobox domain (IPR001356) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251416 control chromosomes (gnomAD). c.386A>G has been reported in the literature in multiple individuals affected with Branchiootic Syndrome 3 and fully co-segregated with disease in a large kindred (Ruf_2004, Ito_2006, Noguchi_2011, Nishio_2015). These data indicate that the variant is very likely to be associated with disease. Experimental evidence evaluating an impact on protein function demonstrated the variant significantly reduced the binding activity of Six1 to DNA, and inhibited the ability of the SIX1-EYA complex to activate transcription (Ruf_2004, Patrick_2009). Three ClinVar submitters (evaluation after 2014) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
not provided, no classification provided	literature only	GeneReviews	-	- -

Branchiootic syndrome 3;C1854594:Autosomal dominant nonsyndromic hearing loss 23;C4551702:Branchiootorenal syndrome 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Branchiootic syndrome 3;C1854594:Autosomal dominant nonsyndromic hearing loss 23 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 23, 2023

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 129 of the SIX1 protein (p.Tyr129Cys). This variant is present in population databases (rs104894478, gnomAD 0.007%). This missense change has been observed in individuals with branchiootorenal spectrum disorders (PMID: 12843324, 15141091, 16652090, 21254961, 21280147). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 8308). 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 SIX1 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects SIX1 function (PMID: 15141091, 19497856). For these reasons, this variant has been classified as Pathogenic. -

Autosomal dominant nonsyndromic hearing loss 23 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Sep 01, 2017

This variant has been previously reported as disease-causing and was found once in our laboratory de novo in a 5-year-old female with bilateral mild-to-moderate sensorineural hearing loss & preauricular pits; father & paternal grandfather had adult-onset conductive hearing loss; mother had preauricular pit -

SIX1-related disorder Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Nov 15, 2023

The SIX1 c.386A>G variant is predicted to result in the amino acid substitution p.Tyr129Cys. This variant has been reported to segregate with branchiootic syndrome (BOS) in one large family with 18 affected individuals and was also found in two additional individuals with BOS from two unrelated families (Ruf et al. 2004. PubMed ID: 15141091; Ito et al. 2006. PubMed ID: 16652090; Noguchi et al. 2011. PubMed ID: 21254961). Functional experiments found this variant reduced DNA binding activity (Ruf et al. 2004. PubMed ID: 15141091; Patrick et al. 2009. PubMed ID: 19497856). This variant is reported in 0.0062% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/14-61115522-T-C). This variant is interpreted as likely pathogenic. -

Branchiootic syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

research

Laboratory of Human Genetics, Universidade de São Paulo

May 01, 2024

The SIX1:c.386A>G: p.Tyr129Cys variant has well-established functional studies that show damaging effect on the gene or gene product (PS3), PS2, Non-truncating non-synonymous variant is located in a mutational hotspot and/or critical and well-established functional domain (PM1), Extremely low frequency in gnomAD population databases (PM2), Different amino acid change as a known pathogenic variant (PM5), Cosegregation with disease in multiple affected family members in a gene definitively known to cause the disease (PP1), computational prediction tools unanimously support a deleterious effect on the gene (PP3), Reported in ClinVar in affected cases (PP5). In our case it was found in one affected individual in heterozygosis, probably inherited from untested affected father. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D;D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	.;D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.9	M;M
MutationTaster	Benign	1.0	A;A;A;A
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-8.3	D;.
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	D;.
Sift4G	Uncertain	0.0030	D;.
Polyphen		1.0	D;D
Vest4		0.75
MutPred		0.88		Loss of phosphorylation at Y129 (P = 0.0483);Loss of phosphorylation at Y129 (P = 0.0483);
MVP		0.97
MPC		2.6
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.92
gMVP		0.85

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: rs104894478; hg19: chr14-61115522;