Diagnosis and follow-up of a case of peroxisomal disorder with peroxisomalmosaicism

Peroxisomal disorder phenotypes are the result of mutations that cause defe ctive peroxisomal assembly or alterations in the import mechanism of peroxi somal proteins that lead to multiple peroxisomal dysfunctions, or the resul t; of a peroxisomal enzymatic deficiency with a single peroxisomal dysfunct ion. With complementation analysis, 16 groups have been found. Assignment o f the genetic defect has been described for some of the complementation gro ups. We describe the clinical evolution and follow-up over 10 years of a pa tient who belongs to complementation group 4, although he showed a milder c linical course. It has been found in fibroblasts different peroxisome popul ations, normal processing and expression of beta-oxidation PTS1 and PTS2 pr oteins, abnormal ALD protein distribution and normal plasmalogen biosynthes is; abnormal beta-oxidation metabolites have also been detected in serum. U ltrastructural studies in liver showed peroxisomal mosaicism as in fibrobla sts. It has been taken into account that peroxisomal mosaicism may lead to variability in peroxisomal diagnostic parameters, making difficult the fina l diagnosis in these patients.