chr16-68022235-T-A

Position:

• chr16-68022235-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_018380.4(DDX28):​c.968A>T​(p.Lys323Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: DDX28 NM_018380.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.34

Genes affected

DDX28 (HGNC:17330): (DEAD-box helicase 28) DEAD box proteins, characterized by the conserved motif Asp-Glu-Ala-Asp (DEAD), are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary structure, such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly. Based on their distribution patterns, some members of the DEAD box protein family are believed to be involved in embryogenesis, spermatogenesis, and cellular growth and division. This gene is intronless. It encodes an RNA-dependent ATPase. The encoded protein is localized in the mitochondria and the nucleus, and can be transported between the mitochondria and the nucleus. [provided by RefSeq, Jul 2008]

DUS2 (HGNC:26014): (dihydrouridine synthase 2) This gene encodes a cytoplasmic protein that catalyzes the conversion of uridine residues to dihydrouridine in the D-loop of tRNA. The resulting modified bases confer enhanced regional flexibility to tRNA. The encoded protein may increase the rate of translation by inhibiting an interferon-induced protein kinase. This gene has been implicated in pulmonary carcinogenesis. Alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, Nov 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.30166733).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DDX28	NM_018380.4	c.968A>T	p.Lys323Ile	missense_variant	1/1	ENST00000332395.7	NP_060850.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DDX28	ENST00000332395.7	c.968A>T	p.Lys323Ile	missense_variant	1/1	6	NM_018380.4	ENSP00000332340.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461892 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 16, 2023

The c.968A>T (p.K323I) alteration is located in exon 1 (coding exon 1) of the DDX28 gene. This alteration results from a A to T substitution at nucleotide position 968, causing the lysine (K) at amino acid position 323 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.56
BayesDel_addAF	Benign	-0.10	T
BayesDel_noAF	Benign	-0.39
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.015	T
Eigen	Benign	0.12
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.60	T
M_CAP	Benign	0.014	T
MetaRNN	Benign	0.30	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.7	L
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-2.1	N
REVEL	Benign	0.14
Sift	Uncertain	0.016	D
Sift4G	Benign	0.13	T
Polyphen		0.16	B
Vest4		0.53
MutPred		0.55		Loss of methylation at K323 (P = 0.0125);
MVP		0.37
MPC		1.3
ClinPred		0.90	D
GERP RS		4.7
Varity_R		0.25
gMVP		0.64

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-68056138;