Peroxisome Biogenesis Disorder 2a (Zellweger)

A number sign (#) is used with this entry because this form of Zellweger syndrome (PBD2A) is caused by homozygous mutation in the PEX5 gene (600414) on chromosome 12p13.

Description

The peroxisome biogenesis disorder (PBD) Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome. 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 2 (CG2) have mutations in the PEX5 gene. For information on the history of PBD complementation groups, see 214100.

Clinical Features

Thomas et al. (1975) described a male patient with hyperpipecolic acidemia. Features were persistent hepatomegaly, severe mental retardation, progressive loss of developmental milestones, and diminished visual acuity associated with nystagmus, abnormal discs, and retinal changes. He died at age 2 years following a progressive loss of neurologic function. Pipecolic acid was present in the serum at a concentration of 4 to 5 mg percent and trace amounts were detected in the urine. The complementation studies of Brul et al. (1988) assigned this patient to complementation group 2 (CG2).

Molecular Genetics

Dodt et al. (1995) reported a homozygous mutation in the PEX5 gene in a cell line from a patient with Zellweger syndrome (600414.0002).