rs773736505

Positions:

• chr11-22236161-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 10P and 1B. PVS1_Moderate PP5_Very_Strong BS2_Supporting

The NM_213599.3(ANO5):​c.649-2A>G variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000486 in 1,439,340 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 0.0000049 (0 hom.)
• Consequence: ANO5 NM_213599.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 8.12

Genes affected

ANO5 (HGNC:27337): (anoctamin 5) This gene encodes a member of the anoctamin family of transmembrane proteins. The encoded protein is likely a calcium activated chloride channel. Mutations in this gene have been associated with gnathodiaphyseal dysplasia. Alternatively spliced transcript variants have been described. [provided by RefSeq, Nov 2009]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.041210797 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.8, offset of 20, new splice context is: gtgtactatattctctcaAGatg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PP5: Variant 11-22236161-A-G is Pathogenic according to our data. Variant chr11-22236161-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 548990.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-22236161-A-G is described in Lovd as [Likely_pathogenic].
• BS2: High AC in GnomAdExome4 at 7 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ANO5	NM_213599.3	c.649-2A>G		splice_acceptor_variant		ENST00000324559.9	NP_998764.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ANO5	ENST00000324559.9	c.649-2A>G		splice_acceptor_variant		1	NM_213599.3	ENSP00000315371	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000486 AC: 7 AN: 1439340 Hom.: 0 Cov.: 28 AF XY: 0.00000279 AC XY: 2 AN XY: 717750

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000641

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Gnathodiaphyseal dysplasia;C1969785:Autosomal recessive limb-girdle muscular dystrophy type 2L Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 27, 2023

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 548990). Disruption of this splice site has been observed in individual(s) with autosomal recessive limb-girdle muscular dystrophy (PMID: 25891276, 32528171). This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 7 of the ANO5 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in ANO5 are known to be pathogenic (PMID: 21186264, 23606453, 25891276, 30919934). -

Autosomal recessive limb-girdle muscular dystrophy type 2L Pathogenic:1

Likely pathogenic, criteria provided, single submitter

research

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

-

The heterozygous c.649-2A>G variant was identified in the compound heterozygous state by our study in one individual with Limb-Girdle Muscular Dystrophy. The c.649-2A>G variant occurs in the invariant region (+/- 1/2) of the splice consensus sequence and is predicted to cause altered splicing leading to an abnormal or absent protein. However, in the absence of RNA/functional studies, the actual effect of this sequence change is unknown. Although this variant has not been previously reported, other canonical splice site variants have been reported in association with ANO5-related disorders (LOVD, ClinVar, HGMD). In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	30
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D
GERP RS		5.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.65		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.65		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs773736505; hg19: chr11-22257707;