CDP-L-ribitol pyrophosphorylase A (CRPPA)

CDP-L-ribitol pyrophosphorylase A (CRPPA) is an enzyme encoded by the CRPPA gene, responsible for producing ribitol 5-phosphate, a precursor for the glycosylation of α-dystroglycan proteins. Glycosylation by CRPPA is critical for anchoring dystroglycan to the extracellular matrix and stabilizing muscle fibers and neural tissue during development. Mutations in CRPPA disrupt this process and result in severe congenital muscular dystrophies such as Walker-Warburg syndrome, which involves muscle weakness and major brain and eye abnormalities. CRPPA is also implicated in milder phenotypes such as limb-girdle muscular dystrophy. At a molecular level, CRPPA belongs to the family of transferases, specifically cytidylyltransferases, and is essential for O-linked glycosylation of specific proteins such as α-dystroglycan. While no drugs are currently approved to target CRPPA directly, substrate supplementation and gene therapy are areas of active research. Biomarkers related to CRPPA dysfunction include abnormal glycosylation of α-dystroglycan detected by muscle biopsy and genetic testing. Safety concerns for therapies center on delivery, off-target effects, and the rapid progression of related diseases.

Other names

D-ribitol-5-phosphate cytidylyltransferaseISPDhISPDhCG_1745121IspDNip2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase-like proteinIsoprenoid synthase domain-containing proteinNotch1-induced proteinMDDGA7LGMDR20MDDGC7ISPD_HUMANTesticular tissue protein Li 97

Drugs would potentially act by modulating substrate supply (ribitol supplementation), enzyme activity augmentation, or gene therapy to correct mutations affecting glycosylation