1-18883049-A-T

Variant names:

• chr1-18883049-A-T
• rs6426611
• NM_003748.4:c.678+75T>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_003748.4(ALDH4A1):​c.678+75T>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000014 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: ALDH4A1 NM_003748.4 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.87
• Publications: 4 publications found

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]

MIR4695 (HGNC:41573): (microRNA 4695) microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.97).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALDH4A1	NM_003748.4	c.678+75T>A		intron_variant	Intron 7 of 14	ENST00000375341.8	NP_003739.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALDH4A1	ENST00000375341.8	c.678+75T>A		intron_variant	Intron 7 of 14	1	NM_003748.4	ENSP00000364490.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000139 AC: 2 AN: 1440898 Hom.: 0 AF XY: 0.00000139 AC XY: 1 AN XY: 718106

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 32998

American (AMR) AF: 0.00 AC: 0 AN: 44648

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26032

East Asian (EAS) AF: 0.00 AC: 0 AN: 39566

South Asian (SAS) AF: 0.00 AC: 0 AN: 85796

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52040

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5652

European-Non Finnish (NFE) AF: 0.00000183 AC: 2 AN: 1094584

Other (OTH) AF: 0.00 AC: 0 AN: 59582

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.006664), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 34

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.97
CADD	Benign	0.0020
DANN	Benign	0.33
PhyloP100		-1.9

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: rs6426611; hg19: chr1-19209543;