Laboratory Diagnosis of Peroxisomal Disorders in the -Omics Era and the Continued Importance of Biomarkers and Biochemical Studies

Abstract The clinical as well as biochemical and genetic spectrum of peroxisomal diseases has markedly increased over the last few years, thanks to the revolutionary advances in the field of genome analysis and several -omics technologies. This has led to the recognition of novel disease phenotypes linked to mutations in previously identified peroxisomal genes as well as several hitherto unidentified peroxisomal disorders. Correct interpretation of the wealth of data especially coming from genome analysis requires functional studies at the level of metabolites (peroxisomal metabolite biomarkers), enzymes, and the metabolic pathway(s) involved. This strategy is not only required to identify the true defect in each individual patient but also to determine the extent of the deficiency as described in detail in this article.

Novel Mutations causing Hyperimmunoglobulin D and Periodic Fever Syndrome.

Hyperimmunoglobulin D and periodic fever syndrome (HIDS) is a rare, hereditary autoinflammatory condition characterized by recurrent inflammatory episodes. We report a 9-year-old boy, diagnosed with HIDS due to two novel mutations, c.62C>T (p.Ala21Val) and c.372-6T>C (probable splicing defect), in the mevalonate kinase (MVK) gene. The pathogenicity of these mutations was confirmed by measurement of low MVK enzyme activity in cultured primary skin fibroblasts of the patient. The symptoms have been refractory to therapy with steroids and non steroidal anti inflammatory drugs. This report expands the genetic and ethnic spectrum of HIDS.

Primary hyperoxaluria type 1 with a novel mutation.

Primary hyperoxaluria type 1 [PH1] is an autosomal recessive disorder caused by a deficiency of alanine-glyoxylate aminotransferase AGT, which is encoded by the AGXT gene. We report an Indian family with two affected siblings having a novel mutation in the AGXT gene inherited from the parents. The index case progressed to end stage renal disease at 5 months of age. His 4 month old sibling is presently under follow up with preserved renal function.