22-25203882-G-C

Variant names:

• chr22-25203882-G-C
• rs17670506
• NM_004076.5:c.314G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_004076.5(CRYBB3):​c.314G>C​(p.Arg105Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,854 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R105Q) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CRYBB3 NM_004076.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.57
• Publications: 0 publications found

Genes affected

CRYBB3 (HGNC:2400): (crystallin beta B3) Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N- and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, is part of a gene cluster with beta-A4, beta-B1, and beta-B2. Mutations in this gene result in cataract congenital nuclear autosomal recessive type 2. [provided by RefSeq, Feb 2013]

CRYBB3 Gene-Disease associations (from GenCC):

• cataract 22 multiple types

  Inheritance: AR, AD, SD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• early-onset anterior polar cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• early-onset nuclear cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• early-onset non-syndromic cataract

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.955

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004076.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRYBB3	NM_004076.5	MANE Select	c.314G>C	p.Arg105Pro	missense	Exon 4 of 6	NP_004067.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CRYBB3	ENST00000215855.7	TSL:1 MANE Select	c.314G>C	p.Arg105Pro	missense	Exon 4 of 6	ENSP00000215855.2
	CRYBB3	ENST00000404334.1	TSL:3	c.314G>C	p.Arg105Pro	missense	Exon 4 of 5	ENSP00000386123.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461854 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727232

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111986

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.59	D
Eigen	Pathogenic	0.78
Eigen_PC	Uncertain	0.61
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Pathogenic	4.0	H
PhyloP100		7.6
PrimateAI	Benign	0.47	T
PROVEAN	Pathogenic	-6.5	D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.60
MutPred		0.82		Gain of catalytic residue at R105 (P = 0.0372)
MVP		0.92
MPC		0.78
ClinPred		1.0	D
GERP RS		3.5
Varity_R		0.97
gMVP		0.97
Mutation Taster		=21/79	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs17670506; hg19: chr22-25599849;