Our verdict is Benign. Variant got -8 ACMG points: 0P and 8B. BP4_StrongBS2
The NM_000918.4(P4HB):c.1483A>G(p.Met495Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000235 in 1,613,730 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).
P4HB (HGNC:8548): (prolyl 4-hydroxylase subunit beta) This gene encodes the beta subunit of prolyl 4-hydroxylase, a highly abundant multifunctional enzyme that belongs to the protein disulfide isomerase family. When present as a tetramer consisting of two alpha and two beta subunits, this enzyme is involved in hydroxylation of prolyl residues in preprocollagen. This enzyme is also a disulfide isomerase containing two thioredoxin domains that catalyze the formation, breakage and rearrangement of disulfide bonds. Other known functions include its ability to act as a chaperone that inhibits aggregation of misfolded proteins in a concentration-dependent manner, its ability to bind thyroid hormone, its role in both the influx and efflux of S-nitrosothiol-bound nitric oxide, and its function as a subunit of the microsomal triglyceride transfer protein complex. [provided by RefSeq, Jul 2008]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 495 of the P4HB protein (p.Met495Val). This variant is present in population databases (rs143647285, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with P4HB-related conditions. 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 tolerated. 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. -