7-50327678-C-T

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_Strong BP7 BS1_Supporting BS2

The NM_006060.6(IKZF1):c.81C>T(p.Gly27=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000242 in 1,613,340 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000092 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: IKZF1 NM_006060.6 synonymous
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.427

Genes affected

IKZF1 (HGNC:13176): (IKAROS family zinc finger 1) This gene encodes a transcription factor that belongs to the family of zinc-finger DNA-binding proteins associated with chromatin remodeling. The expression of this protein is restricted to the fetal and adult hemo-lymphopoietic system, and it functions as a regulator of lymphocyte differentiation. Several alternatively spliced transcript variants encoding different isoforms have been described for this gene. Most isoforms share a common C-terminal domain, which contains two zinc finger motifs that are required for hetero- or homo-dimerization, and for interactions with other proteins. The isoforms, however, differ in the number of N-terminal zinc finger motifs that bind DNA and in nuclear localization signal presence, resulting in members with and without DNA-binding properties. Only a few isoforms contain the requisite three or more N-terminal zinc motifs that confer high affinity binding to a specific core DNA sequence element in the promoters of target genes. The non-DNA-binding isoforms are largely found in the cytoplasm, and are thought to function as dominant-negative factors. Overexpression of some dominant-negative isoforms have been associated with B-cell malignancies, such as acute lymphoblastic leukemia (ALL). [provided by RefSeq, May 2014]

ACMG classification

Verdict is Benign. Variant got -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.61).
• BP7: Synonymous conserved (PhyloP=-0.427 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000092 (14/152106) while in subpopulation AFR AF= 0.000338 (14/41412). AF 95% confidence interval is 0.000204. There are 0 homozygotes in gnomad4. There are 6 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd at 14 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IKZF1	NM_006060.6	c.81C>T	p.Gly27=	synonymous_variant	3/8	ENST00000331340.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IKZF1	ENST00000331340.8	c.81C>T	p.Gly27=	synonymous_variant	3/8	1	NM_006060.6	A1

Frequencies

GnomAD3 genomes AF: 0.0000920 AC: 14 AN: 152106 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000338

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000283 AC: 7 AN: 247608 Hom.: 0 AF XY: 0.0000446 AC XY: 6 AN XY: 134624

Gnomad AFR exome AF: 0.000131

Gnomad AMR exome AF: 0.0000581

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: 0.0000268

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461234 Hom.: 0 Cov.: 30 AF XY: 0.0000234 AC XY: 17 AN XY: 726852

Gnomad4 AFR exome AF: 0.000329

Gnomad4 AMR exome AF: 0.0000448

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000990

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000920 AC: 14 AN: 152106 Hom.: 0 Cov.: 32 AF XY: 0.0000807 AC XY: 6 AN XY: 74318

Gnomad4 AFR AF: 0.000338

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000987 Hom.: 0

Bravo AF: 0.000110

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 12, 2023

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 or were not evaluated, and the effect of this variant on mRNA splicing is currently unknown. ClinVar contains an entry for this variant (Variation ID: 1972188). This variant has not been reported in the literature in individuals affected with IKZF1-related conditions. This variant is present in population databases (rs369941285, gnomAD 0.03%). This sequence change affects codon 27 of the IKZF1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the IKZF1 protein. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.61
Cadd	Benign	4.3
Dann	Benign	0.91

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

LitVar

Other links and lift over

dbSNP: rs369941285; hg19: chr7-50367274; COSMIC: COSV58783244;