Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2BS2
The NM_002880.4(RAF1):āc.1922C>Gā(p.Thr641Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000684 in 1,461,888 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (ā ā ).
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_benign. Variant got -3 ACMG points.
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.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.T641R variant (also known as c.1922C>G), located in coding exon 16 of the RAF1 gene, results from a C to G substitution at nucleotide position 1922. The threonine at codon 641 is replaced by arginine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -