Tsugutoshi Aoki

Molecular analysis and diagnosis in Japanese patients with Wilson's disease.

Abstract Background: Wilson’s disease is characterized by the toxic accumulation of copper in the liver, brain, cornea and other organs. It is caused by both impaired excretion via the bile and impaired incorporation of copper into ceruloplasmin in the liver. The Wilson’s disease gene (ATP7B) has been cloned as a putative copper‐transporting P‐type ATPase gene. We therefore analysed mutations of ATP7B in Japanese patients with Wilson’s disease.

Treatment and management of Wilson's disease

Abstract Wilson’s disease is an autosomal recessive disorder related to the copper metabolism. The clinical symptoms are due to copper deposition in various tissues, including liver, brain, kidney, cornea and others. The key strategy of treatment is to reduce the amount of copper in the liver and other tissues by administering both copper‐chelating agents and a low copper diet. D‐Penicillamine is considered to be the first choice as a copper‐chelating agent. Patients require 15–25 mg/kg daily in the early stages of treatment and this drug should also be given more than 2 h before meals. Some undesirable or serious side‐effects, such as systemic lupus erythematosus (SLE) and nephrotic syndrome, do occur in 20–25% of all patients. In such cases, trienthylene tetramine (trientine) appears to be as effective as penicillamine. This drug is usually used when D‐penicillamine has to be withdrawn. It is also sometimes administered to patients with neurological symptoms as a first‐choice drug. It is given in doses of 40–50 mg/kg daily, in the same manner as for D‐penicillamine. Zinc salt administration has also emerged as an interesting supportive therapy for both treatments. A dose of 5–7.5 mg/kg daily is given before meals. The copper content of the diet should be less than 1 mg/day in the early stages of treatment. Thereafter, it can be increased to 1.0–1.5 mg/day during well‐controlled periods. Liver transplantation is now performed in many countries for patients with either the fulminant or chronic progressive types of Wilson’s disease.

Two families with Wilson disease in which siblings showed different phenotypes

AbstractWe 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.

Glycine cleavage system in ketotic hyperglycinemia: a reduction of H-protein activity.

Glycine cleavage activity was compared in the livers from three cases of ketotic hyperglycinemia (two cases of propionic acidemia and one case of methylmalonic acidemia) and three controls. In one case of propionic acidemia, glycine cleavage activity (5.2 nmole/mg protein/hr) was normal in the liver obtained at biopsy when the patient was well controlled by the treatment with low protein diet (0.8 g/kg/day) and the level of serum glycine was lowered to normal. In the two other cases of ketotic hyperglycinemia, glycine cleavage activity was significantly reduced in the liver obtained at autopsy when the patients died in the state of metabolic acidosis. Its activity in the liver of one case of propionic acidemia (0.7 nmole/mg protein/hr) was 6–26% of that in controls (2.7–10.8 nmole/mg protein/hr), and 2–7% in a case of methylmalonic acidemia (0.2 nmole/mg protein/hr).Analysing of the individual components of the glycine cleavage system, a marked decrease in the activity of H-protein was revealed in the livers of the both patients; it (0.2 nmole/mg protein/ hr) was only 3–4% of that in controls (4.9–6.3 nmole/mg protein/ hr). These findings suggest that the reduction of the glycine cleavage system in the liver of ketotic hyperglycinemia occurs secondarily as speculated previously and is caused mainly by a decrease of H-protein activity.Speculation: The reduction of glycine cleavage activity in ketotic hyperglycinemia may be caused at first by an inactivation of H-protein. Subsequently the activities of other components of the glycine cleavage system may be decreased.

Factors contributing to cerebral hypomyelination in the growth hormone-deficientlittle mouse

We attempted to delineate the events leading to hypomyelination in the brain of thelittle 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 thelittle and normal mice first became apparent on the 10th day of age. Thereafter, the rate of increase in thelittle brain consistently lagged behind the normal. [3H]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 thelittle brain. These findings indicate that the hypomyelination of the mutant cerebrum might result from reduced oligodendroglial proliferation due to growth hormone deficiency.

Mouthpiece versus facemask for delivery of nebulized salbutamol in exacerbated childhood asthma.

We compared the bronchodilator response to salbutamol (albuterol) delivered by a compressed air nebulizer through a mouthpiece and via a facemask in 18 asthmatic children, to determine the most appropriate delivery method. Patients using a mouthpiece had significantly better mean percent increases in forced expiratory volume in 1 sec (FEV1) and in forced vital capacity (FVC) than those using a facemask 30 min after inhalation (FEV1: 56.4 ± 32.6 % vs. 28.9 ± 19.1%, FVC: 34.4 ± 26.4% vs. 7.5 ± 14.9%, respectively). Nebulized therapy plays an important role in the management of bronchial asthma in children and should be delivered by a mouthpiece whenever possible in cases of exacerbated asthma.

MRI in the mild type of mucopolysaccharidosis II (Hunter's syndrome).

We report imaging findings in a 3-year-old boy with the typical mild type of Hunters disease. MRI revealed multifocal large cyst- or spindle-like areas of increased and decreased signal in the white matter, including the corpus callosum on T1- and T2-weighted images. The white matter showed high signal on T2-weighted images, isointense with cerebrospinal fluid on all other pulse sequences. To our knowledge, these appearances have not been reported in this disorder. Deposition of mucopolysaccharide and/or glycolipid and increase in fluid content seem to be responsible.

Threshold Concentration of Unbound Bilirubin to Induce Neurological Deficits in a Patient with Type I Crigler—Najjar Syndrome

Based on the clinical course of a 16-year-old boy with type I Crigler-Najjar syndrome, we estimated the threshold concentration of unbound bilirubin, as assayed by the horseradish peroxidase method, that apparently induces toxicity to the brain. Before the age of 15, the patient did not manifest any neurological or behavioural dysfunction despite increased bilirubin in serum. The binding affinity and the binding capacity of the patients serum albumin for bilirubin determined when he was about 14 years old were 108(mol/L)−1 and 1·01 to 1·04 mol/L, respectively. These values were nearly the same as those of normal controls reported in the literature. The total bilirubin binding capacity was greater than the patients total bilirubin concentration, showing that his serum albumin was not saturated with bilirubin. The reserve bilirubin binding capacity (RBBC) was estimated to be 158 μmol/L and the unbound bilirubin concentration to be 15·1 nmol/L. Concentration of unbound bilirubin peaked at 21·7 nmol/L at the age of 15 years and 11 months, i.e. 2 months before the onset of difficulties in walking and speaking. At this time, the RBBC was estimated as −64 μmol/L. A peak concentration of total bilirubin, 811 μmol/L, was observed during the period of rapid loss of the ability to walk or speak. At the age of 16 years and 1 month the RBBC decreased to −98 μmol/L and the unbound bilirubin concentration to 18·8 nmol/L. Following phototherapy, the patients neurological state returned to normal; he could speak and walk normally. At the age of 16 years and 2 months the RBBC returned to 105 μmol/L and unbound bilirubin decreased to 16·6 nmol/L. These results suggest that maintaining the concentration of unbound bilirubin at < 20 nmol/L and the total bilirubin concentration at lower than the binding capacity of serum albumin is important for prevention of neurological deficits in Crigler-Najjar syndrome. The upper limit of unbound bilirubin in such an older patient was nearly the same as that reported for newborns.

Early and presymptomatic detection of Wilson's disease at the mandatory 3-year-old medical health care examination in Hokkaido Prefecture with the use of a novel automated urinary ceruloplasmin assay.

Wilsons disease (WND) is an autosomal recessive disorder of copper (Cu) accumulation leading to liver and/or brain damage. Oral chelating agents and diet are effective in treating WND. However, once irreversible damage has occurred, the effect of treatment is diminished and the patients quality of life is compromised. For these reasons an effective method for screening has been needed for early detection of presymptomatic patients. We conducted an early and presymptomatic detection of WND using a novel automated assay of ceruloplasmin (Cp) concentration in urine and selected the mandatory medical health care examination for 3-year-old children in Hokkaido Prefecture (the largest administrative division in Japan) as a sampling point. We measured urinary Cp concentrations in 11,362 children using an immunological latex agglutination assay kit developed by us. Among these children we identified a positive case with markedly reduced urinary Cp concentration. Detailed medical examination provided no clinical manifestations to support the diagnosis of WND, although serum Cp and Cu levels were remarkably low in this case. Therefore, we analyzed the WND gene in order to confirm the diagnosis. Sequence analysis revealed that the case was compound heterozygous for the WND gene mutations 2871del.C and D1296N. According to the Ferenci scoring system for WND diagnosis, the case was established as a WND patient at the presymptomatic stage. Consequently, the patient has maintained a good quality of life under medical treatment with polaprezinc administration to date. Our investigation suggests that the screening system for WND using the automated urinary assay at the mandatory medical health care examination for 3-year-old children is a noninvasive and efficient method for the early and presymptomatic diagnosis of WND.

Acute myeloblastic leukemia associated with trisomy 8 and translocation 8;21 in a child with Down syndrome

The present study examined an 11-year-old girl with Down syndrome who suffered from acute myeloblastic leukemia (AML) preceded by preleukemic pancytopenia. Chromosomal analysis of leukemic cells revealed a chromosome change at t(8;21) and trisomy 8 associated with constitutional trisomy 21. Treatment with antineoplastic agents led to complete remission.