Glucose-6-phosphatase deficiency (G6P deficiency), or glycogen storage disease type I (GSDI), is a group of inherited metabolic diseases, including types Ia and Ib, characterized by poor tolerance to fasting, growth retardation and hepatomegaly resulting from accumulation of glycogen and fat in the liver. Prevalence is unknown and annual incidence is around 1/100,000 births. GSDIa is the more frequent type, representing about 80% of GSDI patients. The disease commonly manifests, between the ages of 3 to 4 months by symptoms of hypoglycemia (tremors, seizures, cyanosis, apnea). Patients have poor tolerance to fasting, marked hepatomegaly, growth retardation (small stature and delayed puberty), generally improved by an appropriate diet, osteopenia and sometimes osteoporosis, full-cheeked round face, enlarged kydneys and platelet dysfunctions leading to frequent epistaxis. In addition, in GSDIb, neutropenia and neutrophil dysfunction are responsible for tendency towards infections, relapsing aphtous gingivostomatitis, and inflammatory bowel disease. Late complications are hepatic (adenomas with rare but possible transformation into hepatocarcinoma) and renal (glomerular hyperfiltration leading to proteinuria and sometimes to renal insufficiency). GSDI is caused by a dysfunction in the G6P system, a key step in the regulation of glycemia. The deficit concerns the catalytic subunit G6P-alpha (type Ia) which is restricted to expression in the liver, kidney and intestine, or the ubiquitously expressed G6P transporter (type Ib). Mutations in the genes G6PC (17q21) and SLC37A4 (11q23) respectively cause GSDIa and Ib. Many mutations have been identified in both genes,. Transmission is autosomal recessive. Diagnosis is based on clinical presentation, on abnormal basal values and absence of hyperglycemic response to glucagon. It can be confirmed by demonstrating a deficient activity of a G6P system component in a liver biopsy. To date, the diagnosis is most commonly confirmed by G6PC (GSDIa) or SLC37A4 (GSDIb) gene analysis, and the indications of liver biopsy to measure G6P activity are getting rarer and rarer. Differential diagnoses include the other GSDs, in particular type III (see this term). However, in GSDIII, glycemia and lactacidemia are high after a meal and low after a fast period (often with a later occurrence than that of type I). Primary liver tumors and Pepper syndrome (hepatic metastases of neuroblastoma) may be evoked but are easily ruled out through clinical and ultrasound data. Antenatal diagnosis is possible through molecular analysis of amniocytes or chorionic villous cells. Pre-implantatory genetic diagnosis may also be discussed. Genetic counseling should be offered to patients and their families. The dietary treatment aims at avoiding hypoglycemia (frequent meals, nocturnal enteral feeding through a nasogastric tube, and later oral addition of uncooked starch) and acidosis (restricted fructose and galactose intake). Liver transplantation, performed on the basis of poor metabolic control and/or hepatoc...

Crigler-Najjar syndrome type I (CN-I, MIM #218800) is a rare and severe autosomal disorder. It is caused by deficiency of the liver enzyme responsible for bilirubin elimination, the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1; EC 2.4.1.17). Biologically, the disease manifests itself with severe and persistent unconjugated hyperbilirubinemia. Kernicterus is a well-known complication of severe unconjugated hyperbilirubinemia in infants and young children, especially in patients with CN-I.Few articles have shown the efficiency of plasmapheresis for extreme hyperbilirubinemia.In this report, we describe the efficiency of plasmapheresis for a rapid control of acute and severe unconjugated hyperbilirubinemia in a 6-year-old CN-I patient who had previously developed kernicterus in the neonatal period. In spite of intensification of phototherapy, the patient developed severe hyperbilirubinemia (up to 830 mmol/l, with bilirubin/albumin ratio at 1.2). With two plasmapheresis procedures, bilirubin serum concentration decreased to 420 mmol/ and bilirubin/albumin ratio to 0.55. Following the acute episode of very severe unconjugated hyperbilirubinemia, the child recovered and neurological examination was unchanged, thus suggesting that plasmapheresis possibly prevented further worsening of kernicterus.

Patients with type I glycogen storage disease (GSD) have poor tolerance to fasting, sometimes less than 3 hours during infancy. Even though most patients are able, as they get older, to tolerate a longer fasting period, they are at permanent risk for fast-induced hypoglycaemia, even in adulthood. Klüver Bucy syndrome, is characterized by psychic blindness (inability to recognize familiar objects), hypermetamorphosis (strong tendency to react to visual stimulus), increased oral exploration, placidity, indiscriminate hyper-sexuality and change in dietary habits. In this case report, we describe the development of Klüver Bucy syndrome in a 28-year-old man with type Ib GSD, following prolonged and severe hypoglycaemia triggered by a common respiratory infection.