Lack of the enzyme phosphatidylinositol
4,5-biphosphate 5-phosphatase, which is located in the Golgi apparatus and
controls the intracellular level of phosphatidylinositol 4,5-biphosphate.
This enzyme deficiency may impair normal intracellular protein sorting
(including second messengers), especially within polarized cells, and could
be responsible for the observed ocular, renal, and cerebral abnormalities.