chr17-29253783-G-C

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_005208.5(CRYBA1):​c.500+1G>C variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.00000342 in 1,461,840 control chromosomes in the GnomAD database, with no homozygous occurrence. There is a variant allele frequency bias in the population database for this variant (GnomAdExome4), which may indicate mosaicism or somatic mutations in the reference population data. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

CRYBA1
NM_005208.5 splice_donor, intron

Scores

4
2
1
Splicing: ADA: 1.000
2

Clinical Significance

Likely pathogenic criteria provided, single submitter P:3

Conservation

PhyloP100: 5.49

Publications

1 publications found
Variant links:
Genes affected
CRYBA1 (HGNC:2394): (crystallin beta A1) 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, encodes two proteins (crystallin, beta A3 and crystallin, beta A1) from a single mRNA, the latter protein is 17 aa shorter than crystallin, beta A3 and is generated by use of an alternate translation initiation site. Deletion of exons 3 and 4 causes the autosomal dominant disease 'zonular cataract with sutural opacities'. [provided by RefSeq, Jul 2008]
CRYBA1 Gene-Disease associations (from GenCC):
  • cataract 10 multiple types
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
  • early-onset lamellar cataract
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • early-onset nuclear cataract
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • early-onset posterior polar cataract
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • early-onset sutural cataract
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.3, offset of 35, new splice context is: aaaGTaact. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 17-29253783-G-C is Pathogenic according to our data. Variant chr17-29253783-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1209931.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CRYBA1NM_005208.5 linkc.500+1G>C splice_donor_variant, intron_variant Intron 5 of 5 ENST00000225387.8 NP_005199.2 P05813-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CRYBA1ENST00000225387.8 linkc.500+1G>C splice_donor_variant, intron_variant Intron 5 of 5 1 NM_005208.5 ENSP00000225387.3 P05813-1
CRYBA1ENST00000484605.1 linkn.*121+1G>C splice_donor_variant, intron_variant Intron 4 of 4 5 ENSP00000464368.1 J3QRT1

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251322
AF XY:
0.00000736
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.0000462
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000342
AC:
5
AN:
1461840
Hom.:
0
Cov.:
32
AF XY:
0.00000550
AC XY:
4
AN XY:
727228
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39694
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86252
European-Finnish (FIN)
AF:
0.0000187
AC:
1
AN:
53406
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000360
AC:
4
AN:
1111992
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.005674), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.395
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
Cov.:
32
Alfa
AF:
0.0000282
Hom.:
0
Bravo
AF:
0.00000378

ClinVar

Significance: Likely pathogenic
Submissions summary: Pathogenic:3
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

not provided Pathogenic:2
-
Genome Diagnostics Laboratory, Amsterdam University Medical Center
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

-
Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Cataract 10 multiple types Pathogenic:1
Apr 04, 2024
Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.63
D
BayesDel_noAF
Pathogenic
0.27
CADD
Pathogenic
31
DANN
Uncertain
0.99
Eigen
Pathogenic
1.1
Eigen_PC
Pathogenic
0.94
FATHMM_MKL
Uncertain
0.93
D
PhyloP100
5.5
GERP RS
4.6
Mutation Taster
=7/93
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
1.0
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.38
Position offset: 16
DS_DL_spliceai
1.0
Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs775038545; hg19: chr17-27580801; API