Up to date 6 OI patients with KDELR2 mutations have been described in 4 families. Homozygous and compound heterozygous frameshift and missense mutations have been identified. KDELR2 encodes the KDEL endoplasmic reticulum protein retention receptor 2, which recycles ER-resident proteins with a KDEL-like peptide from the cis-Golgi to the ER through COPI retrograde transport. Patient cells show decreased expression of HSP47 and FKBP65 as well as abnormal quality of secreted collagen fibrils.
Diagnostic testing can be performed with next generation sequencing in the form of targeted panels or whole-exome sequencing.
KDELR2