Peroxisomal disorders. Zellweger syndrome (cerebro-hepato-renal syndrome)
Incidence
Relatively common. AR inheritance.Absent peroxisomes in liver. Multiple peroxisomal enzymes absent. Defective synthesis of plasmalogen. Incidence 1 in 50.000 to 1 in 100,000
Clinical Characteristics
Typical facial dysmorphism: high forehead, wide fontanels, low & broad nasal bridge, epicanthus, external ear deformity, redundant skin folds in neck,. Severe hypotonia, absent or > depressed DTRs, poor sucking & swallowing, Seizures since birth. FTT. Severe psychomotor delay (arrest), retinal degeneration, absent ERG. Optic atrophy, cataracts, glaucoma may occur. Hepatomegaly & abn. LFT always present, freq. polycystic kidneys. Skeletal deformities,Stippled calcific. of patella. Death usually occurs in the first 6-8 months of life.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
Very long chain fatty acids (VLCFA) increased in blood by GC/MS, mainly hexacosanoic acid (C26:0). Absent peroxisomes in liver & other tissues. Elevated pipecolic acid (after 1 month). Also elevated phitanic acid & medium chain dicarboxilic acids increased in urine. Trihydrocholestanoic acid and dihydrocholestanoic acid are consistently elevated in plasma.