Phytanic acid oxidase deficiency

SUMMARY Fourchildren eachexhibiting aprofound deficiency ofphytanic acidoxidase activity incultured skinfibroblasts butwithverydifferent phenotypes, aredescribed. A consistently raised plasmaphytanic acidvalue, generally considered tobepathognomonic forRefsum's disease (phytanic acid oxidase deficiency), was observed inthree ofthese children butnotinthe fourth, whoalso showed no evidence ofaccumulation ofphytanic acidinliver orfatbiopsies. Our datasuggest thattheclinical diagnosis ofRefsum's disease inchildren ismore difficult because thefull spectrumofclinical features usually observed inadults withthedisorder isnotalways present. Moreover, a failure todetect a raised plasma phytanic acidvalue may notnecessarily indicate normalfibroblast phytanic acidoxidase activity.