Our verdict is Likely pathogenic. Variant got 6 ACMG points: 7P and 1B. PM1PM2PM5PP2BP4
The NM_007315.4(STAT1):c.812A>T(p.Gln271Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign 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. Q271P) 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 6 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 chr2-190995193-T-G is described in Lovd as [Pathogenic].
PP2
Missense variant in the STAT1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 64 curated pathogenic missense variants (we use a threshold of 10). The gene has 19 curated benign missense variants. Gene score misZ: 5.1492 (above the threshold of 3.09). Trascript score misZ: 7.0181 (above the threshold of 3.09). GenCC associations: The gene is linked to Mendelian susceptibility to mycobacterial diseases due to partial STAT1 deficiency, autoimmune enteropathy and endocrinopathy - susceptibility to chronic infections syndrome, immunodeficiency 31B.
BP4
Computational evidence support a benign effect (MetaRNN=0.3177691).