rs776064587

Positions:

• chr4-39465283-AGATATGCCT-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_006859.4(LIAS):​c.553_561del​(p.Met185_Asp187del) variant causes a splice acceptor, coding sequence change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,648 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LIAS NM_006859.4 splice_acceptor, coding_sequence
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.38

Genes affected

LIAS (HGNC:16429): (lipoic acid synthetase) The protein encoded by this gene belongs to the biotin and lipoic acid synthetases family. Localized in the mitochondrion, this iron-sulfur enzyme catalyzes the final step in the de novo pathway for the biosynthesis of lipoic acid, a potent antioxidant. The deficient expression of this enzyme has been linked to conditions such as diabetes, atherosclerosis and neonatal-onset epilepsy. Alternative splicing occurs at this locus, and several transcript variants encoding distinct isoforms have been identified. [provided by RefSeq, Aug 2020]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.050938338 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.5, offset of 0 (no position change), new splice context is: gtggattcttttgtttctAGatg. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LIAS	NM_006859.4	c.553_561del	p.Met185_Asp187del	splice_acceptor_variant, coding_sequence_variant	6/11	ENST00000640888.2	NP_006850.2
LIAS	NM_001278590.2	c.553_561del	p.Met185_Asp187del	splice_acceptor_variant, coding_sequence_variant	6/10		NP_001265519.1
LIAS	NM_194451.3	c.553_561del	p.Met185_Asp187del	splice_acceptor_variant, coding_sequence_variant	6/10		NP_919433.1
LIAS	NM_001363700.2	c.299+1682_299+1690del		intron_variant			NP_001350629.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LIAS	ENST00000640888.2	c.553_561del	p.Met185_Asp187del	splice_acceptor_variant, coding_sequence_variant	6/11	1	NM_006859.4	ENSP00000492260	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249964 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135114

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000293

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460648 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 726612

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000225

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Lipoic acid synthetase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 23, 2017

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. Experimental studies and prediction algorithms are not available for this variant, and the functional significance of the duplicated amino acids is currently unknown. This variant has not been reported in the literature in individuals with LIAS-related disease. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the ExAC database. This variant, c.553_561del, results in the deletion of 3 amino acid(s) of the LIAS protein (p.Met185_Asp187del), but otherwise preserves the integrity of the reading frame. -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs776064587; hg19: chr4-39466903;