A new report, scheduled for publication in the journal Ophthalmology (Vol/ 120, Iss. 12, Dec 2013, pp 2697-2705) has shown that certain compound heterozygous mutations in the mevalonate kinase (MVK) gene, usually associated with a rare disease phenotype, may also cause non-syndromic retinitis pigmentosa (RP). Mevalonate kinase deficiency (MKD), characterized by psychomotor retardation, progressive cerebellar ataxia and recurrent febrile crises manifests in both severe and mild clinical types and is known to arise from a number of mutations in the melavonate kinase gene, understood to code for a key enzyme in the isoprenoid pathway.