NM_001080.3:c.819delT

Variant names:

• chr6-24515258-CT-C
• rs778127154
• NM_001080.3:c.819delT

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1 PP5_Very_Strong

The NM_001080.3(ALDH5A1):​c.819delT​(p.Asp274IlefsTer27) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000123 in 1,461,848 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: ALDH5A1 NM_001080.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: -0.717
• Publications: 1 publications found

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]

ALDH5A1 Gene-Disease associations (from GenCC):

• succinic semialdehyde dehydrogenase deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 6-24515258-CT-C is Pathogenic according to our data. Variant chr6-24515258-CT-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 521941.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALDH5A1	NM_001080.3	c.819delT	p.Asp274IlefsTer27	frameshift_variant	Exon 5 of 10	ENST00000357578.8	NP_001071.1
ALDH5A1	NM_170740.1	c.858delT	p.Asp287IlefsTer27	frameshift_variant	Exon 6 of 11		NP_733936.1
ALDH5A1	NM_001368954.1	c.727-5142delT		intron_variant	Intron 4 of 8		NP_001355883.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALDH5A1	ENST00000357578.8	c.819delT	p.Asp274IlefsTer27	frameshift_variant	Exon 5 of 10	1	NM_001080.3	ENSP00000350191.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.0000557 AC: 14 AN: 251472 AF XY: 0.0000294

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000405

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000123 AC: 18 AN: 1461848 Hom.: 0 Cov.: 35 AF XY: 0.00000688 AC XY: 5 AN XY: 727222

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.000402 AC: 18 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111992

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000936 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Succinate-semialdehyde dehydrogenase deficiency Pathogenic:3

Dec 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Asp274Ilefs*27) in the ALDH5A1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ALDH5A1 are known to be pathogenic (PMID: 14635103). This variant is present in population databases (rs778127154, gnomAD 0.04%). 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: 521941). For these reasons, this variant has been classified as Pathogenic. -

Mar 08, 2021

Elsea Laboratory, Baylor College of Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Feb 15, 2024

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.006%). Predicted Consequence/Location: Frameshift: predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant. The variant has been reported at least twice as pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000521941 /PMID: 31440721). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

Inborn genetic diseases Pathogenic:1

Mar 25, 2025

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.819delT (p.D274Ifs*27) alteration, located in exon 5 (coding exon 5) of the ALDH5A1 gene, consists of a deletion of one nucleotide at position 819, causing a translational frameshift with a predicted alternate stop codon after 27 amino acids. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from gnomAD, this variant has an overall frequency of 0.006% (14/251472) total alleles studied. The highest observed frequency was 0.041% (14/34592) of Admixed American alleles. This variant has been identified in conjunction with other ALDH5A1 variant(s) in individual(s) with features consistent with succinic semialdehyde dehydrogenase deficiency (Schreiber, 2021). Based on the available evidence, this alteration is classified as pathogenic. -

not provided Pathogenic:1

Jul 26, 2022

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 14635103) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.72
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs778127154; hg19: chr6-24515486;