X-72330078-T-C

Variant names:

• chrX-72330078-T-C
• rs1131690790
• NM_018486.3:c.1112-2A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_018486.3(HDAC8):​c.1112-2A>G variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: HDAC8 NM_018486.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 4.18
• Publications: 0 publications found

Genes affected

HDAC8 (HGNC:13315): (histone deacetylase 8) Histones play a critical role in transcriptional regulation, cell cycle progression, and developmental events. Histone acetylation/deacetylation alters chromosome structure and affects transcription factor access to DNA. The protein encoded by this gene belongs to class I of the histone deacetylase family. It catalyzes the deacetylation of lysine residues in the histone N-terminal tails and represses transcription in large multiprotein complexes with transcriptional co-repressors. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2009]

HDAC8 Gene-Disease associations (from GenCC):

• Cornelia de Lange syndrome

  Inheritance: AD, XL Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• Cornelia de Lange syndrome 5

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• Wilson-Turner syndrome

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000285547 (HGNC:):

ACMG classification

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

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.49470899 fraction of the gene.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HDAC8	NM_018486.3	c.1112-2A>G		splice_acceptor_variant, intron_variant	Intron 10 of 10	ENST00000373573.9	NP_060956.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HDAC8	ENST00000373573.9	c.1112-2A>G		splice_acceptor_variant, intron_variant	Intron 10 of 10	1	NM_018486.3	ENSP00000362674.3
ENSG00000285547	ENST00000648922.1	c.1111+21655A>G		intron_variant	Intron 10 of 11			ENSP00000497072.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cornelia de Lange syndrome 5 Pathogenic:1 Uncertain:1

Jul 31, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects an acceptor splice site in the last intron (intron 10) of the HDAC8 gene. While this is not anticipated to result in nonsense mediated decay, it likely alters RNA splicing and results in a disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with HDAC8-related disease. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. 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. -

May 31, 2017

Institute of Human Genetics, University of Goettingen

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	27
DANN	Uncertain	0.99
FATHMM_MKL	Uncertain	0.82	D
PhyloP100		4.2
GERP RS		5.1
Mutation Taster		=13/87	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.94		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.94		Position offset: -2

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

Other links and lift over

dbSNP: rs1131690790; hg19: chrX-71549928;