Peroxisomal disorders. Infantile Refsum disease (Phytanic acid oxidase deficiency).
Incidence
AR inheritance. Seems to be a mild peroxisomal disorder with absent number of peroxisomes in liver.
Clinical Characteristics
Normal neonatal period. After several months start non-specific Sx. Dysmorphic facies, retinitis pigmentosa, sensorineural hearing loss, mental retardation. There is pipecolic acidemia and very long chain fatty acids (VLCFA) are markedly elevated. Hepatomegaly, Abn LFT, low cholesterol & apolipoproteins in plasma. Developmental delay, sensorineural hearing loss, hypotonia, ataxic gait & choroidorethinopathy present by 1-3 years. Most pts survive > 10 yrs.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
VLCFA (notably C26:0) are elevated x3. Also pipecolic acid in plasma & CSF. Phytanic acid elevated. Decreased plasmalogen content in RBCs & cultured Fibroblasts. Defective dihydroxyacetone phosphate acyltransferase in Fibrob.