rs1555330109

Positions:

• chr14-53054495-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001160148.2(DDHD1):​c.2380A>C​(p.Thr794Pro) 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 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 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: DDHD1 NM_001160148.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.329

Genes affected

DDHD1 (HGNC:19714): (DDHD domain containing 1) This gene is a member of the intracellular phospholipase A1 gene family. The protein encoded by this gene preferentially hydrolyzes phosphatidic acid. It is a cytosolic protein with some mitochondrial localization, and is thought to be involved in the regulation of mitochondrial dynamics. Overexpression of this gene causes fragmentation of the tubular structures in mitochondria, while depletion of the gene results in mitochondrial tubule elongation. Deletion of this gene in male mice caused fertility defects, resulting from disruption in the organization of the mitochondria during spermiogenesis. In humans, mutations in this gene have been associated with hereditary spastic paraplegia (HSP), also known as Strumpell-Lorrain disease, or, familial spastic paraparesis (FSP). This inherited disorder is characterized by progressive weakness and spasticity of the legs. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Aug 2015]

DDHD1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.13981077).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DDHD1	NM_001160148.2	c.2380A>C	p.Thr794Pro	missense_variant	11/13	ENST00000673822.2	NP_001153620.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DDHD1	ENST00000673822.2	c.2380A>C	p.Thr794Pro	missense_variant	11/13		NM_001160148.2	ENSP00000500986.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461822 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727206

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: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 28 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 15, 2018

In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a DDHD1-related disease. This sequence change replaces threonine with proline at codon 801 of the DDHD1 protein (p.Thr801Pro). The threonine residue is moderately conserved and there is a small physicochemical difference between threonine and proline. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.073
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.54
CADD	Benign	13
DANN	Benign	0.95
DEOGEN2	Benign	0.21	.;.;T;.
Eigen	Benign	-0.39
Eigen_PC	Benign	-0.54
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.66	T;T;T;T
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.14	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.58	.;.;N;N
PrimateAI	Benign	0.31	T
PROVEAN	Benign	-0.90	.;N;N;N
REVEL	Benign	0.27
Sift	Benign	0.087	.;T;T;T
Sift4G	Benign	0.17	T;D;T;D
Polyphen		0.98, 0.98	.;.;D;D
Vest4		0.19
MutPred		0.53		.;.;Gain of relative solvent accessibility (P = 0.0082);Gain of relative solvent accessibility (P = 0.0082);
MVP		0.082
MPC		1.0
ClinPred		0.15	T
GERP RS		1.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.048
gMVP		0.46

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

LitVar

Other links and lift over

dbSNP: rs1555330109; hg19: chr14-53521213;