Identification of a novel mutation in PEX16 in a patient with Peroxisomal disorders: a case report

Introduction: Defect in any of the 13peroxisomal biogenesis factor(PEX) genes can lead to peroxisome deficiency or complete lack of its function. Peroxisomal disorders are the diseases developed due to peroxisome deficiency. The main symptoms of these diseases include ataxia, hypotonia, severe neurodevelopmental delay, hepatomegaly, renal cysts, sensorineural deafness, and retinal dysfunction.Materials & Methods: Case presentation This study presents a new mutation in the PEX16 gene associated with Peroxisomal disorders. The patient, a Balouchian girl originating from Hormozgan (Iran), presented with progressive ataxia at the age of 3. The patient was completely normal by age 3. But his older brother also suffers from similar conditions as well as neurodevelopmental delay features. It should be noted that his parents are the first cousin and the patient have a healthy sister. According to the patient s symptoms, and also given the presence of an affected brother, at the first step, we took an MRI test of the patient, which the result was normal. Subsequently, biochemical tests (including disorders of amino acids metabolisms, disorders of beta-oxidation of fatty acids, disorders of carnitine metabolisms, disorders of organic acids, defects of urea cycle) that were likely to reveal the origin of the defect were assigned to the patient but no pathological results obtained. Finally, whole-exome sequencing test was done for the patient. The results showed a novel homozygous missensemutation (c.C859T) in exon 9 of the PEX16 gene. After this observation we perform the sanger sequencing for his parents and his brother. As a result, his parent has a heterozygous mutation in the same gene and same location. The remarkable point is that after doing sanger sequencing for the proband’s brother, it was observed that his brother also had the same mutation in the same location.Conclusions: This case emphasizes the significance of doing peroxisomal screening tests (such as biochemical, functional, and genetic tests) in patients with clinical manifestations slighter than those usually observed in Peroxisomal disorders.Conclusion & discussion: This case emphasizes the significance of doing peroxisomal screening tests (such as biochemical, functional, and genetic tests) in patients with clinical manifestations slighter than those usually observed in Peroxisomal disorders.