Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1PM2PP2PP3_Moderate
The NM_002880.4(RAF1):c.1193G>A(p.Arg398His) variant causes a missense, splice region 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).
RAF1 (HGNC:9829): (Raf-1 proto-oncogene, serine/threonine kinase) This gene is the cellular homolog of viral raf gene (v-raf). The encoded protein is a MAP kinase kinase kinase (MAP3K), which functions downstream of the Ras family of membrane associated GTPases to which it binds directly. Once activated, the cellular RAF1 protein can phosphorylate to activate the dual specificity protein kinases MEK1 and MEK2, which in turn phosphorylate to activate the serine/threonine specific protein kinases, ERK1 and ERK2. Activated ERKs are pleiotropic effectors of cell physiology and play an important role in the control of gene expression involved in the cell division cycle, apoptosis, cell differentiation and cell migration. Mutations in this gene are associated with Noonan syndrome 5 and LEOPARD syndrome 2. [provided by RefSeq, Jul 2008]
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
PM1
In a domain Protein kinase (size 260) in uniprot entity RAF1_HUMAN there are 6 pathogenic changes around while only 1 benign (86%) in NM_002880.4
PM2
Very rare variant in population databases, with high coverage;
PP2
Missense variant in the RAF1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 47 curated pathogenic missense variants (we use a threshold of 10). The gene has 39 curated benign missense variants. Gene score misZ: 2.4628 (below the threshold of 3.09). Trascript score misZ: 3.4185 (above the threshold of 3.09). GenCC associations: The gene is linked to Noonan syndrome 5, dilated cardiomyopathy 1NN, Noonan syndrome with multiple lentigines, Noonan syndrome, cardiofaciocutaneous syndrome, familial isolated dilated cardiomyopathy, LEOPARD syndrome 2, Costello syndrome.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.884
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 398 of the RAF1 protein (p.Arg398His). This variant also falls at the last nucleotide of exon 11, which is part of the consensus splice site for this exon. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with RAF1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1034621). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). 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. -