X-17721439-A-T

Variant names:

• chrX-17721439-A-T
• rs786205257
• NM_001291867.2:c.916-2A>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001291867.2(NHS):​c.916-2A>T 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 Pathogenic (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: NHS NM_001291867.2 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.32
• Publications: 0 publications found

Genes affected

NHS (HGNC:7820): (NHS actin remodeling regulator) This gene encodes a protein containing four conserved nuclear localization signals. The encoded protein functions in eye, tooth, craniofacial and brain development, and it can regulate actin remodeling and cell morphology. Mutations in this gene have been shown to cause Nance-Horan syndrome, and also X-linked cataract-40. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, May 2014]

NHS Gene-Disease associations (from GenCC):

• Nance-Horan syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: ClinGen, Orphanet, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• early-onset nuclear cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000309710 (HGNC:):

ACMG classification

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 9.6, offset of 13, new splice context is: tttgctgtcccatcccccAGagg. 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 X-17721439-A-T is Pathogenic according to our data. Variant chrX-17721439-A-T is described in ClinVar as Pathogenic. ClinVar VariationId is 1363083.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NHS	NM_001291867.2	c.916-2A>T		splice_acceptor_variant, intron_variant	Intron 4 of 8	ENST00000676302.1	NP_001278796.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NHS	ENST00000676302.1	c.916-2A>T		splice_acceptor_variant, intron_variant	Intron 4 of 8		NM_001291867.2	ENSP00000502262.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Nance-Horan syndrome Pathogenic:1

Mar 08, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. 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. Disruption of this splice site has been observed in individual(s) with Nance-Horan syndrome (PMID: 16736028). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (ExAC no frequency). This sequence change affects an acceptor splice site in intron 3 of the NHS 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 NHS are known to be pathogenic (PMID: 14564667, 19414485). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.040
CADD	Pathogenic	35
DANN	Uncertain	0.99
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		6.3
GERP RS		5.9
Mutation Taster		=2/98	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.96		Position offset: 15
DS_AL_spliceai		0.99		Position offset: 2

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

Other links and lift over

dbSNP: rs786205257; hg19: chrX-17739559;