1-33092209-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_052998.4(AZIN2):c.439C>T(p.His147Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,672 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: AZIN2 NM_052998.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.97

Genes affected

AZIN2 (HGNC:29957): (antizyme inhibitor 2) The protein encoded by this gene belongs to the antizyme inhibitor family, which plays a role in cell growth and proliferation by maintaining polyamine homeostasis within the cell. Antizyme inhibitors are homologs of ornithine decarboxylase (ODC, the key enzyme in polyamine biosynthesis) that have lost the ability to decarboxylase ornithine; however, retain the ability to bind to antizymes. Antizymes negatively regulate intracellular polyamine levels by binding to ODC and targeting it for degradation, as well as by inhibiting polyamine uptake. Antizyme inhibitors function as positive regulators of polyamine levels by sequestering antizymes and neutralizing their effect. This gene encodes antizyme inhibitor 2, the second member of this gene family. Like antizyme inhibitor 1, antizyme inhibitor 2 interacts with all 3 antizymes and stimulates ODC activity and polyamine uptake. However, unlike antizyme inhibitor 1, which is ubiquitously expressed and localized in the nucleus and cytoplasm, antizyme inhibitor 2 is predominantly expressed in the brain and testis and localized in the endoplasmic reticulum-golgi intermediate compartment. Recent studies indicate that antizyme inhibitor 2 is also expressed in specific cell types in ovaries, adrenal glands and pancreas, and in mast cells. The exact function of this gene is not known, however, available data suggest its role in cell growth, spermiogenesis, vesicular trafficking and secretion. Accumulation of antizyme inhibitor 2 has also been observed in brains of patients with Alzheimer's disease. There has been confusion in literature and databases over the nomenclature of this gene, stemming from an earlier report that a human cDNA clone (identical to ODCp/AZIN2) had arginine decarboxylase (ADC) activity (PMID:14738999). Subsequent studies in human and mouse showed that antizyme inhibitor 2 was devoid of arginine decarboxylase activity (PMID:19956990). Alternatively spliced transcript variants have been described for this gene. [provided by RefSeq, Sep 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.30649656).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
AZIN2	NM_052998.4	c.439C>T	p.His147Tyr	missense_variant	6/12	ENST00000294517.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AZIN2	ENST00000294517.11	c.439C>T	p.His147Tyr	missense_variant	6/12	1	NM_052998.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461672 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727136

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000180

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

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 11, 2023

The c.439C>T (p.H147Y) alteration is located in exon 6 (coding exon 3) of the AZIN2 gene. This alteration results from a C to T substitution at nucleotide position 439, causing the histidine (H) at amino acid position 147 to be replaced by a tyrosine (Y). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.089
BayesDel_addAF	Benign	-0.10	T
BayesDel_noAF	Benign	-0.39
Cadd	Benign	21
Dann	Benign	0.97
DEOGEN2	Benign	0.40	T;T;.
Eigen	Benign	-0.038
Eigen_PC	Benign	0.11
FATHMM_MKL	Uncertain	0.94	D
M_CAP	Benign	0.0076	T
MetaRNN	Benign	0.31	T;T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Benign	0.44	T
PROVEAN	Uncertain	-4.2	D;D;D
REVEL	Benign	0.10
Sift	Benign	0.13	T;T;T
Sift4G	Benign	0.23	T;T;T
Polyphen		0.22	B;B;B
Vest4		0.38
MutPred		0.70		Loss of disorder (P = 0.0411);Loss of disorder (P = 0.0411);Loss of disorder (P = 0.0411);
MVP		0.061
MPC		0.21
ClinPred		0.92	D
GERP RS		4.5
Varity_R		0.33
gMVP		0.56

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-33557810;