Sovik et al. (1975) reported a boy who developed generalized seizures on the second day of life and was found to have severe hypoglycemia. He also had frequent attacks of cyanosis and apnea. At age 8 weeks, he ... Sovik et al. (1975) reported a boy who developed generalized seizures on the second day of life and was found to have severe hypoglycemia. He also had frequent attacks of cyanosis and apnea. At age 8 weeks, he showed general retardation and atrophy of the optic nerve. At age 3.5 months, he underwent subtotal pancreatectomy and treatment with diazoxide to inhibit insulin production. However, poor response of the hypoglycemia to this treatment prompted the authors to consider a defect in gluconeogenesis. By studies on the patient's liver, Vidnes and Sovik (1976,1976) demonstrated that he had a defect of gluconeogenesis due to deficiency of cytosolic phosphoenolpyruvate carboxykinase (PCK1; 614168). The total activity of the enzyme was normal, but the enzyme showed an abnormal subcellular distribution, with virtually no activity detected in the cytosolic fraction of a liver homogenate. He died at age 2 years, 10 months. Postmortem examination showed severe cerebral atrophy, atrophy of the optic nerve, fatty infiltration of the liver, kidney, and heart, and hyperplasia of the pancreatic islets of Langerhans. The findings suggested that cytosolic PCK initiates gluconeogenesis at birth. See 261650 for a discussion of mitochondrial PCK deficiency.