Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1PM2PM5PP2
The NM_007315.4(STAT1):c.854A>T(p.Gln285Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. Q285R) has been classified as Pathogenic.
STAT1 (HGNC:11362): (signal transducer and activator of transcription 1) The protein encoded by this gene is a member of the STAT protein family. In response to cytokines and growth factors, STAT family members are phosphorylated by the receptor associated kinases, and then form homo- or heterodimers that translocate to the cell nucleus where they act as transcription activators. The protein encoded by this gene can be activated by various ligands including interferon-alpha, interferon-gamma, EGF, PDGF and IL6. This protein mediates the expression of a variety of genes, which is thought to be important for cell viability in response to different cell stimuli and pathogens. The protein plays an important role in immune responses to viral, fungal and mycobacterial pathogens. Mutations in this gene are associated with Immunodeficiency 31B, 31A, and 31C. [provided by RefSeq, Jun 2020]
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
PM1
In a coiled_coil_region (size 181) in uniprot entity STAT1_HUMAN there are 33 pathogenic changes around while only 1 benign (97%) in NM_007315.4
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr2-190995151-T-C is described in Lovd as [Pathogenic].
PP2
Missense variant in gene, where missense usually causes diseases (based on misZ statistic), STAT1. . Gene score misZ 5.1492 (greater than the threshold 3.09). Trascript score misZ 7.0181 (greater than threshold 3.09). GenCC has associacion of gene with Mendelian susceptibility to mycobacterial diseases due to partial STAT1 deficiency, autoimmune enteropathy and endocrinopathy - susceptibility to chronic infections syndrome, immunodeficiency 31B.