11-111911609-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001289808.2(CRYAB):c.116C>A(p.Pro39Gln) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P39L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CRYAB NM_001289808.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.14

Genes affected

CRYAB (HGNC:2389): (crystallin alpha B) Mammalian lens crystallins are divided into alpha, beta, and gamma families. Alpha crystallins are composed of two gene products: alpha-A and alpha-B, for acidic and basic, respectively. Alpha crystallins can be induced by heat shock and are members of the small heat shock protein (HSP20) family. They act as molecular chaperones although they do not renature proteins and release them in the fashion of a true chaperone; instead they hold them in large soluble aggregates. These heterogeneous aggregates consist of 30-40 subunits; the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional functions of alpha crystallins are an autokinase activity and participation in the intracellular architecture. The encoded protein has been identified as a moonlighting protein based on its ability to perform mechanistically distinct functions. Alpha-A and alpha-B gene products are differentially expressed; alpha-A is preferentially restricted to the lens and alpha-B is expressed widely in many tissues and organs. Elevated expression of alpha-B crystallin occurs in many neurological diseases; a missense mutation cosegregated in a family with a desmin-related myopathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2019]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.819

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CRYAB	NM_001289808.2	c.116C>A	p.Pro39Gln	missense_variant	1/3	ENST00000650687.2
CRYAB	NM_001289807.1	c.116C>A	p.Pro39Gln	missense_variant	2/4
CRYAB	NM_001368245.1	c.116C>A	p.Pro39Gln	missense_variant	2/4
CRYAB	NM_001885.3	c.116C>A	p.Pro39Gln	missense_variant	2/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CRYAB	ENST00000650687.2	c.116C>A	p.Pro39Gln	missense_variant	1/3		NM_001289808.2	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Dilated cardiomyopathy 1II Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 28, 2018

This variant has not been reported in the literature in individuals with CRYAB-related disease. 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. 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: "Probably Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency). This sequence change replaces proline with glutamine at codon 39 of the CRYAB protein (p.Pro39Gln). The proline residue is highly conserved and there is a moderate physicochemical difference between proline and glutamine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.69	D;D;D;D;D;D;T;T;T;T;T
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Uncertain	0.086	D
MetaRNN	Pathogenic	0.82	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.64	D
MutationAssessor	Uncertain	2.5	M;M;M;M;M;M;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Benign	0.44	T
PROVEAN	Uncertain	-3.1	D;.;D;D;D;D;D;D;D;D;D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.0020	D;.;D;D;D;D;D;T;T;D;D
Sift4G	Benign	0.084	T;T;T;T;T;T;.;.;D;.;.
Polyphen		1.0	D;D;D;D;D;D;.;.;D;.;.
Vest4		0.43
MutPred		0.58		Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);Loss of glycosylation at T40 (P = 0.0501);
MVP		0.99
MPC		0.88
ClinPred		0.98	D
GERP RS		5.1
Varity_R		0.84
gMVP		0.60

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: rs149787233; hg19: chr11-111782333; COSMIC: COSV99909977; COSMIC: COSV99909977;