chr6-24503288-G-A

Position:

• chr6-24503288-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001080.3(ALDH5A1):​c.464G>A​(p.Gly155Glu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: ALDH5A1 NM_001080.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.54

Genes affected

ALDH5A1 (HGNC:408): (aldehyde dehydrogenase 5 family member A1) This protein belongs to the aldehyde dehydrogenase family of proteins. This gene encodes a mitochondrial NAD(+)-dependent succinic semialdehyde dehydrogenase. A deficiency of this enzyme, known as 4-hydroxybutyricaciduria, is a rare inborn error in the metabolism of the neurotransmitter 4-aminobutyric acid (GABA). In response to the defect, physiologic fluids from patients accumulate GHB, a compound with numerous neuromodulatory properties. Two transcript variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.967

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALDH5A1	NM_001080.3	c.464G>A	p.Gly155Glu	missense_variant	3/10	ENST00000357578.8
ALDH5A1	NM_170740.1	c.464G>A	p.Gly155Glu	missense_variant	3/11
ALDH5A1	NM_001368954.1	c.464G>A	p.Gly155Glu	missense_variant	3/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALDH5A1	ENST00000357578.8	c.464G>A	p.Gly155Glu	missense_variant	3/10	1	NM_001080.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Succinate-semialdehyde dehydrogenase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 04, 2017

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 ALDH5A1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with glutamic acid at codon 155 of the ALDH5A1 protein (p.Gly155Glu). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and glutamic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.17
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.62	D;T;.
Eigen	Uncertain	0.44
Eigen_PC	Uncertain	0.36
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.97	D;D;D
MetaSVM	Pathogenic	0.90	D
MutationAssessor	Uncertain	2.0	M;.;M
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Pathogenic	-7.9	D;D;D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0060	D;D;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.80
MutPred		0.76		Gain of disorder (P = 0.0719);.;Gain of disorder (P = 0.0719);
MVP		0.97
MPC		1.1
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.88
gMVP		0.97

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs1554136421; hg19: chr6-24503516;