7-50537877-C-T

Position:

• chr7-50537877-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_001082971.2(DDC):​c.418G>A​(p.Gly140Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: DDC NM_001082971.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.90

Genes affected

DDC (HGNC:2719): (dopa decarboxylase) The encoded protein catalyzes the decarboxylation of L-3,4-dihydroxyphenylalanine (DOPA) to dopamine, L-5-hydroxytryptophan to serotonin and L-tryptophan to tryptamine. Defects in this gene are the cause of aromatic L-amino-acid decarboxylase deficiency (AADCD). AADCD deficiency is an inborn error in neurotransmitter metabolism that leads to combined serotonin and catecholamine deficiency. Multiple alternatively spliced transcript variants encoding different isoforms have been identified for this gene. [provided by RefSeq, Jun 2011]

DDC-AS1 (HGNC:40171): (DDC antisense RNA 1)

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a region_of_interest 2 X approximate tandem repeats (size 120) in uniprot entity DDC_HUMAN there are 8 pathogenic changes around while only 1 benign (89%) in NM_001082971.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.975

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DDC	NM_001082971.2	c.418G>A	p.Gly140Arg	missense_variant	4/15	ENST00000444124.7	NP_001076440.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DDC	ENST00000444124.7	c.418G>A	p.Gly140Arg	missense_variant	4/15	1	NM_001082971.2	ENSP00000403644.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461872 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727228

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: 0.00000180

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

Deficiency of aromatic-L-amino-acid decarboxylase Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 19, 2021

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. 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 disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with DDC-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with arginine at codon 140 of the DDC protein (p.Gly140Arg). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Uncertain	26
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.77	D;.;T;.;.;D;.
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	.;D;D;D;.;D;D
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Uncertain	0.39	D
MutationAssessor	Pathogenic	4.2	H;H;.;.;H;H;H
PrimateAI	Uncertain	0.54	T
PROVEAN	Pathogenic	-6.5	D;.;.;.;D;D;D
REVEL	Pathogenic	0.73
Sift	Pathogenic	0.0	D;.;.;.;T;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D
Polyphen		1.0	D;.;.;.;.;D;.
Vest4		0.89
MutPred		0.84		Gain of methylation at G140 (P = 0.0352);Gain of methylation at G140 (P = 0.0352);Gain of methylation at G140 (P = 0.0352);.;Gain of methylation at G140 (P = 0.0352);Gain of methylation at G140 (P = 0.0352);Gain of methylation at G140 (P = 0.0352);
MVP		0.91
MPC		1.1
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.97
gMVP		0.97

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: chr7-50605575;