Detection of a Novel Homozygous PEX5 Stop-Loss Variant Associated with Zellweger Syndrome in a Highly Endogamic Family

Zellweger syndrome (ZS) is a heterogeneous group of clinical conditions that commonly manifest with neurodevelopmental delay, multiple neurological abnormalities, visual and auditory impairments, and adrenocortical dysfunction. ZS is an autosomal recessive peroxisomal disorder resulting from mutations in one of over 13 identified genes. We report the case of a male child with episodic seizures starting at 18 days of life, followed by neurodevelopmental delay and neuroimaging findings of asymmetric polymicrogyria and cortical abnormalities. His healthy parents were consanguineous, and notably, a brother, who passed away at the age of 5 years-old, had epilepsy and adrenoleukodystrophy. Exome sequencing allowed the identification of a novel stop-loss homozygous variant in the <i>PEX5</i> gene in the index case. The phenotype associated to this gene, Zellweger syndrome, as well as the inheritance mechanism, is consistent with that observed in both the patient and his brother.