NM_178452.6:c.1698+1G>A

Variant names:

• chr16-84174723-G-A
• rs139519641
• NM_178452.6:c.1698+1G>A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PVS1_Moderate PM2 BS1_Supporting

The NM_178452.6(DNAAF1):​c.1698+1G>A variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000404 in 1,614,196 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00039 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00040 (0 hom.)
• Consequence: DNAAF1 NM_178452.6 splice_donor, intron
• Scores: Splicing: ADA: 0.9997
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:7 B:1
• Conservation: PhyloP100: 0.405

Genes affected

DNAAF1 (HGNC:30539): (dynein axonemal assembly factor 1) The protein encoded by this gene is cilium-specific and is required for the stability of the ciliary architecture. It is involved in the regulation of microtubule-based cilia and actin-based brush border microvilli. Mutations in this gene are associated with primary ciliary dyskinesia-13. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.024793388 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.3, offset of 6, new splice context is: aagGTcatt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• BS1: Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.000394 (60/152318) while in subpopulation AMR AF= 0.00118 (18/15298). AF 95% confidence interval is 0.00076. There are 0 homozygotes in gnomad4. There are 29 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DNAAF1	NM_178452.6	c.1698+1G>A		splice_donor_variant, intron_variant	Intron 10 of 11	ENST00000378553.10	NP_848547.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DNAAF1	ENST00000378553.10	c.1698+1G>A		splice_donor_variant, intron_variant	Intron 10 of 11	1	NM_178452.6	ENSP00000367815.5

Frequencies

GnomAD3 genomes AF: 0.000394 AC: 60 AN: 152200 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000121

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00118

Gnomad ASJ AF: 0.00144

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.0000943

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.000367

Gnomad OTH AF: 0.00192

GnomAD3 exomes AF: 0.000418 AC: 105 AN: 251466 Hom.: 0 AF XY: 0.000464 AC XY: 63 AN XY: 135922

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00101

Gnomad ASJ exome AF: 0.00218

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000352

Gnomad OTH exome AF: 0.00114

GnomAD4 exome AF: 0.000405 AC: 592 AN: 1461878 Hom.: 0 Cov.: 35 AF XY: 0.000424 AC XY: 308 AN XY: 727236

Gnomad4 AFR exome AF: 0.000358

Gnomad4 AMR exome AF: 0.000872

Gnomad4 ASJ exome AF: 0.00195

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000348

Gnomad4 FIN exome AF: 0.0000374

Gnomad4 NFE exome AF: 0.000366

Gnomad4 OTH exome AF: 0.000695

GnomAD4 genome AF: 0.000394 AC: 60 AN: 152318 Hom.: 0 Cov.: 33 AF XY: 0.000389 AC XY: 29 AN XY: 74476

Gnomad4 AFR AF: 0.000120

Gnomad4 AMR AF: 0.00118

Gnomad4 ASJ AF: 0.00144

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.0000943

Gnomad4 NFE AF: 0.000368

Gnomad4 OTH AF: 0.00190

Alfa AF: 0.000653 Hom.: 0

Bravo AF: 0.000468

TwinsUK AF: 0.000270 AC: 1

ALSPAC AF: 0.000519 AC: 2

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000349 AC: 3

ExAC AF: 0.000305 AC: 37

EpiCase AF: 0.000436

EpiControl AF: 0.000296

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:7 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Primary ciliary dyskinesia 13 Uncertain:3

Sep 08, 2021

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 10, 2020

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Mar 26, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Primary ciliary dyskinesia Uncertain:2

Aug 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 10 of the DNAAF1 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 DNAAF1 are known to be pathogenic (PMID: 19944400, 19944405). This variant is present in population databases (rs139519641, gnomAD 0.2%). This variant has not been reported in the literature in individuals affected with DNAAF1-related conditions. ClinVar contains an entry for this variant (Variation ID: 242159). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

Aug 31, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1698+1G>A intronic variant results from a G to A substitution one nucleotide after coding exon 10 of the DNAAF1 gene. Alterations that disrupt the canonical splice site are expected to result in aberrant splicing. In silico splice site analysis predicts that this alteration may weaken the native splice donor site. The resulting transcript is predicted to be in-frame and is not expected to trigger nonsense-mediated mRNAdecay; however, direct evidence is unavailable. The exact functional effect of the altered amino acid sequence is unknown. This nucleotide position is well conserved in available vertebrate species. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Heterotaxy Pathogenic:1

Apr 24, 2021

Pediatric Genetics Clinic, Sheba Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

not provided Uncertain:1

Feb 12, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed with a DNAAF1 missense variant on the opposite allele (in trans) in an individual with severe early onset obesity, however variants in other genes were also identified (PMID: 25158045); Canonical splice site variant predicted to result in an in-frame loss of the adjacent exon in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 19944405, 19944400, 28492532, 27884173, 27996046, 31980526, 31589614, 34768622, 35051411, 38112957, 25158045, 34215651) -

DNAAF1-related disorder Uncertain:1

Apr 29, 2024

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The DNAAF1 c.1698+1G>A variant is predicted to disrupt the GT donor site and interfere with normal splicing. This variant has been reported along with a DNAAF1 missense variant in a child with recurrent respiratory tract infections and severe obesity; this individual was also found to harbor variants in other phenotype-relevant genes (Patient 2, Paz-Filho et al. 2014. PubMed ID: 25158045). This variant is reported in 0.21% of alleles in individuals of Ashkenazi Jewish descent in gnomAD, which is greater than expected for a pathogenic variant. To our knowledge, no other splicing variants have been reported for this exon. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

not specified Benign:1

May 10, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1698+1G>A variant in DNAAF1 is classified as benign because it has been id entified in 1.1% (60/4820) of chromosomes, including 3 homozygotes without disea se, by the Saudi Human Genome Program (Abouelhoda 2016). This variant has also b een identified in 0.24% of Ashkenazi Jewish chromosomes by the Genome Aggregatio n Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs139519641). This v ariant occurs in the invariant region (+/- 1,2) of the splice consensus sequence and is predicted to cause altered splicing, though a second predicted splice si te is 6 nucleotides downstream, and if used will lead to an in-frame insertion o f 2 amino acids. ACMG/AMP criteria applied: PP3, BA1. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Benign	-0.70
CADD	Benign	16
DANN	Benign	0.58
Eigen	Uncertain	0.22
Eigen_PC	Benign	-0.15
FATHMM_MKL	Benign	0.13	N
GERP RS		2.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.76
SpliceAI score (max)		0.46		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.46		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs139519641; hg19: chr16-84208329;