1-18871805-G-A

Position:

• chr1-18871805-G-A

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The ENST00000290597.9(ALDH4A1):​c.*42-15C>T variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00832 in 152,362 control chromosomes in the GnomAD database, including 16 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0083 (16 hom., cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: ALDH4A1 ENST00000290597.9 splice_polypyrimidine_tract, intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.818

Genes affected

ALDH4A1 (HGNC:406): (aldehyde dehydrogenase 4 family member A1) This protein belongs to the aldehyde dehydrogenase family of proteins. This enzyme is a mitochondrial matrix NAD-dependent dehydrogenase which catalyzes the second step of the proline degradation pathway, converting pyrroline-5-carboxylate to glutamate. Deficiency of this enzyme is associated with type II hyperprolinemia, an autosomal recessive disorder characterized by accumulation of delta-1-pyrroline-5-carboxylate (P5C) and proline. Alternatively spliced transcript variants encoding different isoforms have been identified for this gene. [provided by RefSeq, Jun 2009]

ACMG classification

Verdict is Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.84).
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00832 (1268/152362) while in subpopulation AFR AF= 0.0277 (1151/41586). AF 95% confidence interval is 0.0263. There are 16 homozygotes in gnomad4. There are 608 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High Homozygotes in GnomAd4 at 16 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ALDH4A1	NM_003748.4	c.*1040C>T		3_prime_UTR_variant	15/15	ENST00000375341.8
ALDH4A1	NM_001161504.2	c.*1040C>T		3_prime_UTR_variant	15/15
ALDH4A1	NM_001319218.2	c.*1040C>T		3_prime_UTR_variant	14/14
ALDH4A1	NM_170726.3	c.*42-15C>T		splice_polypyrimidine_tract_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ALDH4A1	ENST00000375341.8	c.*1040C>T		3_prime_UTR_variant	15/15	1	NM_003748.4	P1
ALDH4A1	ENST00000538839.5	c.*1040C>T		3_prime_UTR_variant	14/14	1
ALDH4A1	ENST00000290597.9	c.*42-15C>T		splice_polypyrimidine_tract_variant, intron_variant		1		P1

Frequencies

GnomAD3 genomes AF: 0.00832 AC: 1266 AN: 152244 Hom.: 16 Cov.: 33

Gnomad AFR AF: 0.0277

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00438

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000621

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000382

Gnomad OTH AF: 0.0100

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 50 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 34

Gnomad4 EAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

GnomAD4 genome AF: 0.00832 AC: 1268 AN: 152362 Hom.: 16 Cov.: 33 AF XY: 0.00816 AC XY: 608 AN XY: 74502

Gnomad4 AFR AF: 0.0277

Gnomad4 AMR AF: 0.00438

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000621

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000382

Gnomad4 OTH AF: 0.00993

Alfa AF: 0.00192 Hom.: 2

Bravo AF: 0.00961

Asia WGS AF: 0.00144 AC: 5 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hyperprolinemia type 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.84
CADD	Benign	2.9
DANN	Benign	0.55

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs76525996; hg19: chr1-19198299;