22-26622630-T-A

Position:

• chr22-26622630-T-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM1 PP3 BS2

The NM_001886.3(CRYBA4):​c.34T>A​(p.Trp12Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000131 in 1,449,798 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 (★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: CRYBA4 NM_001886.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.12

Genes affected

CRYBA4 (HGNC:2396): (crystallin beta A4) 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 acidic group member, is part of a gene cluster with beta-B1, beta-B2, and beta-B3. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM1: In a chain Beta-crystallin A4 (size 194) in uniprot entity CRBA4_HUMAN there are 10 pathogenic changes around while only 2 benign (83%) in NM_001886.3
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.759
• BS2: High AC in GnomAdExome4 at 19 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CRYBA4	NM_001886.3	c.34T>A	p.Trp12Arg	missense_variant	2/6	ENST00000354760.4	NP_001877.1
CRYBA4	XM_006724140.4	c.49T>A	p.Trp17Arg	missense_variant	4/8		XP_006724203.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CRYBA4	ENST00000354760.4	c.34T>A	p.Trp12Arg	missense_variant	2/6	1	NM_001886.3	ENSP00000346805	P1
CRYBA4	ENST00000466315.1	n.50T>A		non_coding_transcript_exon_variant	2/5	5

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD3 exomes AF: 0.0000677 AC: 17 AN: 251236 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135838

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000492

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: 0.0000131 AC: 19 AN: 1449798 Hom.: 0 Cov.: 32 AF XY: 0.00000831 AC XY: 6 AN XY: 721606

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000405

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: 0.00

Gnomad4 OTH exome AF: 0.0000168

GnomAD4 genome Cov.: 30

Bravo AF: 0.0000151

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 23 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 24, 2022

This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 12 of the CRYBA4 protein (p.Trp12Arg). This variant is present in population databases (rs760976886, gnomAD 0.05%), and has an allele count higher than expected for a pathogenic variant. This variant has not been reported in the literature in individuals affected with CRYBA4-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C65"). 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	0.73
BayesDel_addAF	Uncertain	0.064	T
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.20	T
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.54	T
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.76	D
MetaSVM	Benign	-0.45	T
MutationAssessor	Uncertain	2.8	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.69	T
PROVEAN	Uncertain	-3.7	D
REVEL	Uncertain	0.60
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.034	D
Polyphen		0.86	P
Vest4		0.93
MutPred		0.50		Gain of disorder (P = 0.0193);
MVP		0.89
MPC		0.70
ClinPred		0.56	D
GERP RS		4.1
Varity_R		0.96
gMVP		0.79

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

Publications

LitVar

Other links and lift over

dbSNP: rs760976886; hg19: chr22-27018594;