6-24495179-C-A

Position:

• chr6-24495179-C-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_001080.3(ALDH5A1):​c.183C>A​(p.Thr61=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000742 in 1,347,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. T61T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.4e-7 (0 hom.)
• Consequence: ALDH5A1 NM_001080.3 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.332

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 Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.3).
• BP7: Synonymous conserved (PhyloP=-0.332 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALDH5A1	NM_001080.3	c.183C>A	p.Thr61=	synonymous_variant	1/10	ENST00000357578.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALDH5A1	ENST00000357578.8	c.183C>A	p.Thr61=	synonymous_variant	1/10	1	NM_001080.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.42e-7 AC: 1 AN: 1347980 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 664752

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: 9.40e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

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

Invitae

Apr 10, 2018

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 sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with ALDH5A1-related disease. While this variant is not present in population databases, the frequency information is unreliable, as metrics indicate poor data quality at this position in the ExAC database. This sequence change affects codon 61 of the ALDH5A1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the ALDH5A1 protein. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.30
CADD	Benign	16
DANN	Benign	0.90

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: rs776791710; hg19: chr6-24495407;