Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PP2PP3
The NM_002880.4(RAF1):c.1517C>T(p.Thr506Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,478 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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]
MKRN2 (HGNC:7113): (makorin ring finger protein 2) This gene encodes a probable E3 ubiquitin ligase containing several zinc finger domains, that is a member of the makorin RING zinc-finger protein family. This gene overlaps the v-raf-1 murine leukemia viral oncogene homolog 1 (RAF1) gene in an antisense orientation and may have a co-regulatory function with RAF1. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2012]
Verdict is Likely_pathogenic. Variant got 6 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, 0.783
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This sequence change replaces threonine with isoleucine at codon 506 of the RAF1 protein (p.Thr506Ile). The threonine residue is moderately conserved and there is a moderate physicochemical difference between threonine and isoleucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with RAF1-related disease. 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. -