7-50537916-C-T

Position:

• chr7-50537916-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_001082971.2(DDC):​c.379G>A​(p.Glu127Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/21 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)
• Consequence: DDC NM_001082971.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0350

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 Uncertain_significance. Variant got 2 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
• BP4: Computational evidence support a benign effect (MetaRNN=0.10104662).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DDC	NM_001082971.2	c.379G>A	p.Glu127Lys	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.379G>A	p.Glu127Lys	missense_variant	4/15	1	NM_001082971.2	ENSP00000403644.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

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

Jul 19, 2022

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 output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The lysine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. ClinVar contains an entry for this variant (Variation ID: 1460840). This variant has not been reported in the literature in individuals affected with DDC-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 127 of the DDC protein (p.Glu127Lys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.64
CADD	Benign	2.1
DANN	Benign	0.97
DEOGEN2	Benign	0.14	T;.;T;.;.;T;.
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.040	N
LIST_S2	Uncertain	0.88	.;D;D;D;.;D;D
M_CAP	Benign	0.0063	T
MetaRNN	Benign	0.10	T;T;T;T;T;T;T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	-1.4	N;N;.;.;N;N;N
PrimateAI	Benign	0.25	T
PROVEAN	Benign	-0.65	N;.;.;.;N;N;N
REVEL	Benign	0.022
Sift	Benign	0.041	D;.;.;.;T;D;T
Sift4G	Benign	0.44	T;T;T;T;T;T;T
Polyphen		0.0	B;.;.;.;.;B;.
Vest4		0.18
MutPred		0.41		Gain of MoRF binding (P = 0.0312);Gain of MoRF binding (P = 0.0312);Gain of MoRF binding (P = 0.0312);.;Gain of MoRF binding (P = 0.0312);Gain of MoRF binding (P = 0.0312);Gain of MoRF binding (P = 0.0312);
MVP		0.25
MPC		0.32
ClinPred		0.068	T
GERP RS		-3.5
Varity_R		0.33
gMVP		0.76

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: chr7-50605614; COSMIC: COSV63565580;