17-8076741-GA-CG

Variant names:

• chr17-8076741-GA-CG
• NM_001139.3:c.1277_1278delTCinsCG
• ALOX12B p.Leu426Pro

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PP2 PP3

The NM_001139.3(ALOX12B):​c.1277_1278delTCinsCG​(p.Leu426Pro) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ALOX12B NM_001139.3 missense, splice_region
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.28
• Publications: 0 publications found

Genes affected

ALOX12B (HGNC:430): (arachidonate 12-lipoxygenase, 12R type) This gene encodes an enzyme involved in the conversion of arachidonic acid to 12R-hydroxyeicosatetraenoic acid. Mutations in this gene are associated with nonbullous congenital ichthyosiform erythroderma. [provided by RefSeq, Sep 2015]

ALOX12B Gene-Disease associations (from GenCC):

• autosomal recessive congenital ichthyosis 2

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
• congenital non-bullous ichthyosiform erythroderma

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
• lamellar ichthyosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• self-healing collodion baby

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_001139.3
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 70 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Trascript score misZ: 1.7573 (below the threshold of 3.09). GenCC associations: The gene is linked to autosomal recessive congenital ichthyosis 2, congenital non-bullous ichthyosiform erythroderma, lamellar ichthyosis, self-healing collodion baby.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001139.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALOX12B	NM_001139.3	MANE Select	c.1277_1278delTCinsCG	p.Leu426Pro	missense splice_region	N/A	NP_001130.1	O75342

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ALOX12B	ENST00000647874.1	MANE Select	c.1277_1278delTCinsCG	p.Leu426Pro	missense splice_region	N/A	ENSP00000497784.1	O75342
	ALOX12B	ENST00000649809.1		c.341_342delTCinsCG	p.Leu114Pro	missense splice_region	N/A	ENSP00000496845.1	A0A3B3IRK2
	ALOX12B	ENST00000577351.5	TSL:5	n.224_225delTCinsCG		splice_region non_coding_transcript_exon	Exon 3 of 5

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.3

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr17-7980059;