<prompt> What is the biochemical defect in the Zellweger syndrome?Peroxisomal biogenesis disorderLysosomal targeting disorderDefect in glycosylation of proteinsTrisomy 21  <response>: Ans. A. Peroxisomal biogenesis disorderBiochemical defect in Zellweger SyndromeThere is gene defects, involving mainly the import of proteins that contain the PTS1 targeting signal Zellweger syndrome most severeClinical picture Typical facial appearance high forehead, unslanting palpebral fissures, hypoplastic supraorbital ridges, and epicanthal folds Severe weakness and hypotonia, neonatal seizures Eye abnormalities cataracts, glaucoma, corneal clouding, Brushfield spots, pigmentary retinopathy, and nerve dysplasia Because of the hypotonia and mongoloid appearance, Down syndrome may be suspected 