The Zellweger syndrome: subcellular pathology, neuropathology, and the demonstration of pneumocystis carinii pneumonitis in two siblings.

The first Scandinavian cases of Zellweger syndrome (ZS) are described. A brother and sister, children of first cousins, had the typical clinical symptoms and pathological findings. Extensive metabolic studies in the boy were negative. Pipecolic acid in the urine was not elevated. Both children died at 14 weeks of age. Two months earlier the girl had suffered severe intestinal bleeding. Both had pneumocystic carinii pneumonia at autopsy although no evidence of immune deficiency had been found in the boy. The girl had used up her visible iron depots while the boy still had abundant but probably physiologic amounts of hemosiderin in the RES. Most of the cerebral abnormalities are unspecfic and possibly related to anoxia or other causes of delayed maturation. The white matter abnormalities in ZS patients may only be quantitatively different from the common "fatty metamorphosis" in infants. Previously reported ultrastructural abnormalities (absence of peroxisomes and very sparse smooth endoplasmic reticulum, as well as mitochondrial abnormalities) which are possibly unique for ZS, are confirmed. It is stressed that these were seen despite phenobarbital treatment which normally stimulates the formation of smooth endoplasmic reticulum.