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We attempted to delineate the events leading to hypomyelination in the brain of the little mouse, a promising murine model of isolated growth hormone deficiency. At 20 days of age, the mutant mouse brain weighed less than its normal counterpart, and this difference in brain weight persisted. Increase in CNPase activity was found to be suppressed in the cerebrum throughout the developmental stage, but not in the other parts of the brain. Differences in cerebral DNA content between the little and normal mice first became apparent on the 10th day of age. Thereafter, the rate of increase in the little brain consistently lagged behind the normal. [H]Thymidine incorporation into the DNA fraction in vivo on the 7th day of age, when glial cell proliferation in the normal cerebrum is most active, was approximately half that of the controls in all parts of the little brain. These findings indicate that the hypomyelination of the mutant cerebrum might result from reduced oligodendroglial proliferation due to growth hormone deficiency. [ABSTRACT FROM AUTHOR]

A 5-year-old boy visited a hospital because of macrocephalus, mental retardation and hepatic dysfunction, and was suspected to have Wilson's disease since his father had this disease. The serum level of ceruloplasmin was low, but urinary copper excretion was not increased markedly. He was treated with D-penicillamine. He was then reffered to our hospital because of his facial features suggesting mucopolysaccharidosis. Based on mucopolysacchariduria and the deficiency of N-acetylglucosaminidase, the diagnosis of Sanfilippo syndrome type B was made. Molecular analyses identified him as a compound heterozygote for both the ATP7B (A844V/2659delG) and alpha-N-acetylglucosaminidase (V241M/R482W) genes, responsible for Wilson's disease and Sanfilippo syndrome type B, respectively. Although born to non-consanguineous parents, he had two rare autosomal recessive diseases. In this case, liver dysfunction was attributed to Wilson's disease, and mental retardation to Sanfilippo syndrome.

Crigler-Najjar syndrome type I is an autosomal recessive disorder with severe unconjugated hyperbilirubinemia, caused by the complete absence of bilirubin uridine 5'-diphosphate-glucuronosyltransferase (UGT) activity. The authors reported a 24-year-old male with this syndrome. He had severe icterus from the age of 4 days, and was diagnosed as having Crigler-Najjar syndrome type I at 51 days after birth. Despite repeated phototherapy, his serum bilirubin was increased. When bilirubin encephalopathy occurred at the age of 16 years, the serum bilirubin level was 47 mg/100 ml. EEG showed diffuse and continuous high voltage slow waves. He was treated with bilirubin adsorption, which reduced the serum bilirubin level to 10-20 mg/100 ml, with disappearance of the EEG abnormality. Subsequent liver transplantation resulted in improvement of neurological signs and symptoms, and recovery of his mental function.

Wilson's disease and Menkes disease are inherited genetic disorders of copper metabolism. Each disease results from the absence or dysfunction of homologous copper-transporting ATPases present in the trans-Golgi network of cells. The Wilson ATPase transports copper into the hepatocyte secretory pathway for incorporation into ceruloplasmin and excretion into the bile. Thus, patients with Wilson's disease of the autosomal recessive trait present with signs and symptoms arising from impaired biliary copper excretion. The Menkes ATPase transports copper across the placenta, gastrointestinal tract, and blood-brain barrier, and the clinical features of this X-linked disease arise from copper deficiency. Despite striking differences in the clinical presentation of these two diseases, the respective ATPases function in precisely the same fashion within the cell. The different clinical features of each disease are the results of the tissue specific expression of these ATPases. In Wilson's disease, impaired biliary copper excretion leads to accumulation of this metal in the liver. When the capacity for hepatic storage is exceeded, cell death ensues, with copper release into the plasma resulting in hemolysis and deposition of copper in extrahepatic tissues. Affected patients usually present in the first or second decade of life with chronic hepatitis and cirrhosis or acute liver failure. Copper accumulation in the cornea results in Kayser-Fleischer rings. Neuropsychiatric symptoms are more common in adults and include dystonia, tremor, personality changes, and cognitive impairment as a results of copper accumulation in the basal ganglia and other brain regions. The diagnosis of Wilson's disease is confirmed by decreased serum ceruloplasmin, increased urinary copper, and elevated hepatic copper concentration. A large number of different mutations occur in the genes of patients with Wilson disease. Copper chelation drugs and zinc are effective in most cases. New treatment guidelines now advise physicians to start patients on zinc.

We investigated two families with Wilson disease in which siblings showed different clinical phenotypes and different ages at onset. In Family 1, the second and fourth male children demonstrated onset of the neurological type of Wilson disease at 16 and 28 years of age, respectively, and the first female child developed the hepatic type at 38 years of age. In Family 2, the second male child showed neurological symptoms at 32 years of age and was diagnosed as having the hepatoneurological type of Wilson disease; then the 35-year-old first female child was found to have the hepatic type by familial screening. We performed mutation analysis of the ATP7B gene for these patients, and found that the mutation was a compound heterozygote in both families. Previous reports of siblings with Wilson disease have shown an identical clinical phenotype and similar ages at onset. In addition, hepatic-type cases generally occur at lower ages compared with the neurological type. In the present investigation, however, younger patients showed neurological symptoms earlier than their older siblings, and clinical phenotypes differed among siblings in both families. These cases appear to be rare. Individual differences in copper accumulation in hepatic cells and intolerance to copper toxicity might be the reason for this phenomenon. Furthermore, there might be a difference in the dominance of the allele expressing ATP7B protein among these cases, resulting in different clinical phenotypes, because all patients of both families were found to be compound heterozygotes.