Zellweger syndrome caused by PEX13 deficiency: report of two novel mutations.

[zellweger syndrome]

Peroxisomal biogenesis disorders represent a group of genetically heterogeneous conditions that have in common failure of proper peroxisomal assembly . Clinically , they are characterized by a spectrum of dysmorphia , neurological , liver , and other organ involvement . To date , mutations in 13 PEX genes encoding peroxins have been identified in patients with peroxisomal biogenesis disorders . Mutations in PEX 13 , which encodes peroxisomal membrane protein PEX 13 , are among the least common causes of peroxisomal biogenesis disorders with only three mutations reported so far . Here , we report on two infants whose clinical and biochemical profile was consistent with classical Zellweger syndrome and whose complementation analysis assigned them both to group H of peroxisomal biogenesis disorders . We show that they harbor two novel mutations in PEX 13 . One patient had a genomic rearrangement resulting in a 147 kb deletion that spans the whole of PEX 13 , while the other had an out-of-frame deletion of 14 bp . This represents the first report of a PEX 13 deletion and suggests that further work is needed to examine the frequency of PEX 13 mutations among Arab patients with peroxisomal biogenesis disorders .