rs753950471

chr8-38247837-T-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1_Moderate PM2 PP3_Strong PP5_Moderate

The NM_015214.3(DDHD2):c.1248+2T>C variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000712 in 1,404,748 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: 31)
  • Exomes 𝑓: 0.0000071 (0 hom.)
• Consequence: DDHD2 NM_015214.3 splice_donor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.23

Genes affected

DDHD2 (HGNC:29106): (DDHD domain containing 2) This gene encodes a phospholipase enzyme containing sterile-alpha-motif (SAM), WWE, and DDHD domains. This protein participates in membrane trafficking between the endoplastic reticulum and the Golgi body. Mutations in this gene can cause autosomal recessive spastic paraplegia 54. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2013]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.057116106 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 8-38247837-T-C is Pathogenic according to our data. Variant chr8-38247837-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 583003.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DDHD2	NM_015214.3	c.1248+2T>C		splice_donor_variant		ENST00000397166.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
DDHD2	ENST00000397166.7	c.1248+2T>C		splice_donor_variant		2	NM_015214.3	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000991 AC: 2 AN: 201732 Hom.: 0 AF XY: 0.0000181 AC XY: 2 AN XY: 110762

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000906

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000712 AC: 10 AN: 1404748 Hom.: 0 Cov.: 27 AF XY: 0.00000858 AC XY: 6 AN XY: 699160

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: 0.000130

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ExAC AF: 0.00000824 AC: 1

Asia WGS AF: 0.000578 AC: 2 AN: 3474

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 54 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Nov 08, 2017

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. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in DDHD2 are known to be pathogenic (PMID: 23176823, 23486545). 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. This variant has not been reported in the literature in individuals with DDHD2-related disease. This variant is present in population databases (rs753950471, ExAC 0.007%). This sequence change affects a donor splice site in intron 10 of the DDHD2 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.31
Cadd	Pathogenic	29
Dann	Uncertain	0.98
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		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: rs753950471; hg19: chr8-38105355;