Peroxisome Biogenesis Disorder 11a (Zellweger)

A number sign (#) is used with this entry because this form of Zellweger syndrome (PBD11A) is caused by homozygous mutation in the PEX13 gene (601789) on chromosome 2p15.

Description

Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006).

For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100.

Individuals with PBDs of complementation group 13 (CG13, equivalent to CGH) have mutations in the PEX13 gene. For information on the history of PBD complementation groups, see 214100.

Clinical Features

Al-Dirbashi et al. (2009) studied 2 Saudi patients, children of consanguineous parents, with Zellweger syndrome who were identified in the neonatal intensive care unit (NICU). The first patient was admitted immediately after birth with severe hypotonia. He had large anterior fontanel and high forehead. Magnetic resonance imaging (MRI) of the brain showed polymicrogyria, lissencephaly, and poor myelination. Consistent with the MRI findings, his electroencephalogram (EEG) revealed cortical dysfunction and seizure activity. He died at 6 weeks of age with cardiopulmonary arrest. The second patient was also admitted to NICU shortly after birth because of severe hypotonia and had anteverted nostrils, a depressed nasal bridge, and a large, triangular face. His course was complicated by recurrent apnea, seizures, and elevated liver enzymes. Renal ultrasound revealed the presence of multiple cysts. He remained in the NICU for 4 months before his transfer to the general pediatrics ward where he remained at 6 months of age with severe failure to thrive, progressive hepatic dysfunction, and global developmental delay.

Molecular Genetics

In a patient with a severe Zellweger syndrome phenotype, Shimozawa et al. (1999) found homozygosity for a nonsense mutation in the PEX13 gene (601789.0001).

One patient with Zellweger syndrome studied by Al-Dirbashi et al. (2009) was homozygous for a large deletion encompassing the entire PEX13 gene (601789.0003); the other patient was homozygous for a smaller, out-of-frame deletion (601789.0004).