15-78105319-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1 PM2 PP5 BP4

The NM_006383.4(CIB2):c.556C>T(p.Arg186Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000533 in 1,614,024 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R186Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.00020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000038 (0 hom.)
• Consequence: CIB2 NM_006383.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4 U:3
• Conservation: PhyloP100: 3.28

Genes affected

CIB2 (HGNC:24579): (calcium and integrin binding family member 2) The protein encoded by this gene is similar to that of KIP/CIB, calcineurin B, and calmodulin. The encoded protein is a calcium-binding regulatory protein that interacts with DNA-dependent protein kinase catalytic subunits (DNA-PKcs), and it is involved in photoreceptor cell maintenance. Mutations in this gene cause deafness, autosomal recessive, 48 (DFNB48), and also Usher syndrome 1J (USH1J). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a chain Calcium and integrin-binding family member 2 (size 186) in uniprot entity CIB2_HUMAN there are 16 pathogenic changes around while only 3 benign (84%) in NM_006383.4
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-78105319-G-A is Pathogenic according to our data. Variant chr15-78105319-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 499480.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=3, Likely_pathogenic=3, Pathogenic=1}. Variant chr15-78105319-G-A is described in Lovd as [Pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.31788698).. Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CIB2	NM_006383.4	c.556C>T	p.Arg186Trp	missense_variant	6/6	ENST00000258930.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CIB2	ENST00000258930.8	c.556C>T	p.Arg186Trp	missense_variant	6/6	1	NM_006383.4	P1

Frequencies

GnomAD3 genomes AF: 0.000204 AC: 31 AN: 152134 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000652

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000319 AC: 8 AN: 251128 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135756

Gnomad AFR exome AF: 0.000431

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: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000376 AC: 55 AN: 1461772 Hom.: 0 Cov.: 30 AF XY: 0.0000330 AC XY: 24 AN XY: 727188

Gnomad4 AFR exome AF: 0.000866

Gnomad4 AMR exome AF: 0.0000224

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: 0.0000198

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome AF: 0.000204 AC: 31 AN: 152252 Hom.: 0 Cov.: 32 AF XY: 0.000215 AC XY: 16 AN XY: 74426

Gnomad4 AFR AF: 0.000650

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000258 Hom.: 0

Bravo AF: 0.000280

ESP6500AA AF: 0.000228 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000494 AC: 6

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4 Uncertain:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1 Uncertain:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 25, 2023	This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 186 of the CIB2 protein (p.Arg186Trp). This variant is present in population databases (rs370359511, gnomAD 0.05%). This missense change has been observed in individuals with non-syndromic sensorineural deafness (PMID: 26426422, 29112224, 34837038). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 499480). 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. Experimental studies have shown that this missense change affects CIB2 function (PMID: 26426422, 28663585). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	May 03, 2022	Published functional studies suggest the R186W variant results in the loss of calcium sequestering ability relative to wild-type (Patel et al., 2015); 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: 28663585, 30174586, 26426422, 29112224, 35440622) -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jan 20, 2017	- -

Autosomal recessive nonsyndromic hearing loss 48 Pathogenic:1

Pathogenic, criteria provided, single submitter

research

Laboratory of Prof. Karen Avraham, Tel Aviv University

Jan 31, 2021

- -

Usher syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

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

Oct 21, 2022

Variant summary: CIB2 c.556C>T (p.Arg186Trp) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 3.2e-05 in 251128 control chromosomes. c.556C>T has been reported in the literature as a homozygous genotype in two affected probands each from at-least two distinct families (Carribean and Yoruba Nigerian) with features of Non-syndromic hearing loss (NSHL) and secondary citations by others (example, Patel_2015, Delio_2015, Booth_2019, Adeyemo_2022). Biallelic loss of function variants in CIB2 have been reported to cause autosomal recessive non-syndromic hearing loss (ARNSHL) and not Usher syndrome (USH) (Booth_2019). These data indicate that the variant is likely to be associated with disease. To our knowledge, no conclusive experimental evidence demonstrating an impact on protein function has been reported, although one study reported p.Arg186Trp mutation affects the calcium binding affinity of CIB2 but did not alter the interactions of CIB2 with Whirlin, nor its targeting to the tips of hair cell stereocilia (Patel_2015). Another study reported this variant as not having notable changes in CIB2 intracellular localization in CHO-K1 cells and no effect on interactions with TMC1 in vitro (Giese_2017). Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (VUS, n=3, P/LP, n=2). Some submitters cite overlapping but not identical evidence utilized in the context of this evaluation. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Childhood onset hearing loss Pathogenic:1

Likely pathogenic, criteria provided, single submitter

research

National Institute on Deafness and Communication Disorders, National Institutes of Health

Jul 08, 2021

PS3_supporting, PM1, PM2_supporting, PM3_supporting, PP1_moderate / Modifications from PMID: 30311386 for classification: The genetic causes of hearing loss have not yet been well characterized in the Yoruba population, and the information regarding variant MAF in this population is still limited, so we did not exclude any variant based on their "high" MAF. PP3 criteria was applied even if the REVEL score was below 0.7, if at least two of the pathogenicity prediction algorithms used predicted that the variant was damaging or likely damaging. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

May 22, 2019

Variant classified as Uncertain Significance - Favor Pathogenic. The p. Arg186Trp variant in CIB2 has been previously reported in the homozygous state in 1 Caribbean Hispanic individual with hearing loss and segregated with disease in 1 affected sibling, also homozygous for the variant (Patel 2015). This variant has been identified in 0.05% (13/24914) of African chromosomes by gnomAD (http://gnomad.broadinstitute.org). This variant is present in ClinVar (Variation ID 499480). Computational prediction tools and conservation analysis suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP criteria applied: PM2_Supporting, PP1, PP3, PM3_Supporting. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Pathogenic	0.27
Cadd	Pathogenic	34
Dann	Pathogenic	1.0
DEOGEN2	Benign	0.34	T;.;.
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Uncertain	0.19	D
MetaRNN	Benign	0.32	T;T;T
MetaSVM	Uncertain	-0.016	T
MutationAssessor	Uncertain	2.6	M;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-6.0	D;D;D
REVEL	Uncertain	0.42
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.59
MVP		0.96
MPC		0.80
ClinPred		0.86	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.54
gMVP		0.72

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: rs370359511; hg19: chr15-78397661;