Zellweger Spectrum Disorder with Nystagmus and Acquired Motor Skill Loss and Short-Term Benefit from IVIG Treatment: A Case Report

Backraund: Zellweger spectrum disorders (ZSD) is a group of autosomal recessive genetic disorders that affect many organs and are mostly caused by mutations in the PEX genes. ZSDs exhibit a wide clinical spectrum ranging from the most severe form, Zellweger syndrome, to the mildest form, Heimler syndrome. Very long and branched chain fatty acid levels in plasma and fibroblasts are biomarkers used in diagnosis. A definitive diagnosis is made through molecular genetic analysis.

Case report: A 14-month-old male patient presented to our clinic with complaints of tremors in the eyes and unsteady gait that had started in recent days. With a preliminary diagnosis of an infectious-related autoimmune disease, the patient was administered pulse steroids and intravenous immunoglobulin (IVIG) treatment. Clinical improvement was observed in the patient`s nystagmus and gait, but the nystagmus complaints increased again later. In the peroxisomal profile examination, elevated levels of plasma phytanic acid, pristanic acid, and very long-chain fatty acids (C26) were detected. Having suspected of Zellweger spectrum disorder, a diet limited from very long-chain fatty acids, phytanic acid, pristanic acid and vitamin supplements (A, D, E, K) were started for the patient.

Results: In the molecular genetic examination, a homozygous c.2528G>A (p.Gly843Asp) pathogenic mutation was detected in the PEX1 gene, and the diagnosis was confirmed.

Conclusion: Zellweger spectrum disorder shows a wide range of clinical variety. While there is no effective treatment; diet, bile acid, and supplements of vitamins A, D, E, and K are employed in treatment. In our patient, IVIG treatment was tried with a preliminary diagnosis of autoimmune, and a short-term partial response was obtained. The IVIG treatment has not been seen to be tried in the literature until now.

Keywords: Zellweger spectrum disorders, PEX1, nystagmus, ataxia, opsoclonus-myoclonus-ataxia syndrome, autoimmune disease, intravenous immunoglobulin