6-24495016-T-G

Variant summary

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

The NM_001080.3(ALDH5A1):c.20T>G(p.Leu7Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000425 in 1,176,142 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. L7L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000043 (0 hom.)
• Consequence: ALDH5A1 NM_001080.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.443

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]

GPLD1 (HGNC:4459): (glycosylphosphatidylinositol specific phospholipase D1) Many proteins are tethered to the extracellular face of eukaryotic plasma membranes by a glycosylphosphatidylinositol (GPI) anchor. The GPI-anchor is a glycolipid found on many blood cells. The protein encoded by this gene is a GPI degrading enzyme. Glycosylphosphatidylinositol specific phospholipase D1 hydrolyzes the inositol phosphate linkage in proteins anchored by phosphatidylinositol glycans, thereby releasing the attached protein from the plasma membrane. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALDH5A1	NM_001080.3	c.20T>G	p.Leu7Arg	missense_variant	1/10	ENST00000357578.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALDH5A1	ENST00000357578.8	c.20T>G	p.Leu7Arg	missense_variant	1/10	1	NM_001080.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000121 AC: 1 AN: 82888 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 47846

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000213

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000425 AC: 5 AN: 1176142 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 569256

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: 0.00000513

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000893 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Apr 19, 2019

Not observed [at a significant frequency] in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Succinate-semialdehyde dehydrogenase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 18, 2022

This sequence change replaces leucine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 7 of the ALDH5A1 protein (p.Leu7Arg). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with ALDH5A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 837293). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt ALDH5A1 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.066
BayesDel_addAF	Uncertain	0.076	D
BayesDel_noAF	Benign	-0.13
Cadd	Uncertain	23
Dann	Uncertain	1.0
DEOGEN2	Benign	0.12	T;T;.
Eigen	Benign	-0.67
Eigen_PC	Benign	-0.58
FATHMM_MKL	Benign	0.053	N
LIST_S2	Benign	0.75	T;T;T
M_CAP	Pathogenic	0.69	D
MetaRNN	Uncertain	0.70	D;D;D
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	0.69	N;.;N
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Uncertain	0.76	T
PROVEAN	Benign	-0.43	N;N;N
REVEL	Uncertain	0.38
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		0.0020	B;.;.
Vest4		0.66
MutPred		0.51		Gain of disorder (P = 0.0028);Gain of disorder (P = 0.0028);Gain of disorder (P = 0.0028);
MVP		0.70
MPC		1.1
ClinPred		0.50	D
GERP RS		1.3
Varity_R		0.34
gMVP		0.66

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: rs774379306; hg19: chr6-24495244;