Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PM5
The NM_002880.4(RAF1):c.766A>T(p.Arg256Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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. R256S) has been classified as Likely pathogenic.
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]
RAF1 Gene-Disease associations (from GenCC):
Noonan syndrome
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
Noonan syndrome 5
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics, PanelApp Australia, G2P
Our verdict: Likely_pathogenic. The variant received 6 ACMG points.
PM1
In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_002880.4
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr3-12604202-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 40599.Status of the report is reviewed_by_expert_panel, 3 stars.