Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1PM2PM5PP2PP3_Strong
The NM_006060.6(IKZF1):c.500A>C(p.His167Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H167Y) has been classified as Likely pathogenic.
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]
Verdict is Pathogenic. Variant got 11 ACMG points.
PM1
?
PM1 - Located in a mutational hot spot and/or critical and well-established functional domain (e.g., active site of an enzyme) without benign variation
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_006060.6
PM2
?
PM2 - Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium
Very rare variant in population databases, with high coverage;
PM5
?
PM5 - Novel missense change at an amino acid residue where a different missense change determined to be pathogenic has been seen before
Other missense variant is known to change same aminoacid residue: Variant chr7-50382618-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 224780.Status of the report is criteria_provided_single_submitter, 1 stars.
PP2
?
PP2 - Missense variant in a gene that has a low rate of benign missense variation and in which missense variants are a common mechanism of disease
Missense variant where missense usually causes diseases, IKZF1
PP3
?
PP3 - Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc.)
MetaRNN computational evidence supports a deleterious effect, 0.954