Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1PM2PM5PP3PP5_Moderate
The NM_001130004.2(ACTN1):c.2212C>G(p.Arg738Gly) 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 pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R738Q) has been classified as Likely pathogenic.
ACTN1 (HGNC:163): (actinin alpha 1) Alpha actinins belong to the spectrin gene superfamily which represents a diverse group of cytoskeletal proteins, including the alpha and beta spectrins and dystrophins. Alpha actinin is an actin-binding protein with multiple roles in different cell types. In nonmuscle cells, the cytoskeletal isoform is found along microfilament bundles and adherens-type junctions, where it is involved in binding actin to the membrane. In contrast, skeletal, cardiac, and smooth muscle isoforms are localized to the Z-disc and analogous dense bodies, where they help anchor the myofibrillar actin filaments. This gene encodes a nonmuscle, cytoskeletal, alpha actinin isoform and maps to the same site as the structurally similar erythroid beta spectrin gene. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Our verdict: Likely_pathogenic. The variant received 9 ACMG points.
PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_001130004.2
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr14-68880029-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1684471.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.839
PP5
Variant 14-68880030-G-C is Pathogenic according to our data. Variant chr14-68880030-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 872047.Status of the report is criteria_provided_single_submitter, 1 stars.
Gain of catalytic residue at R738 (P = 0.0258);Gain of catalytic residue at R738 (P = 0.0258);Gain of catalytic residue at R738 (P = 0.0258);.;Gain of catalytic residue at R738 (P = 0.0258);.;