Ikuko Takahashi

Active hypothalamic-pituitary-gonadal axis in an infant with X-linked adrenal hypoplasia congenita

To evaluate the hypothalamic-pituitary-gonadal axis in an infant with adrenal hypoplasia congenita, we measured the serum levels of testosterone and performed a luteinizing hormone-releasing hormone stimulation test. The diagnosis was made because of the presence of a mutation, A300V, in the DAX-1 gene. The results demonstrated an active hypothalamic-pituitary-gonadal axis, with adult-level testosterone of 266 ng/dl on day 0, and maintenance of testosterone concentration in the 100 to 250 ng/dl range for 140 days as expected. The luteinizing hormone-releasing hormone lest was compatible with an active pituitary gland with a luteinizing hormone peak of 13.1 IU/L and a follicle-stimulating hormone of 5.0 IU/L We conclude that the DAX-1 mutation does allow a normal reproductive axis at birth. We speculate that sometime between infancy and puberty this mutation in the DAX-1 gene leads to an inability to activate the reproductive axis from its childhood suppression; thus puberty will not develop in this infant.

Childhood multiple sclerosis treated with plasmapheresis

We report a case of multiple sclerosis in a 7-year-old boy. He experienced three episodes in 8 months and was repeatedly treated with a high dose of methylprednisolone. During the third episode, to avoid the side effects associated with frequent high doses of steroid, we substituted plasmapheresis for methylprednisolone, initially performing it for 3 days and continuing it every 2 to 3 weeks according to the fluctuating values of antinuclear antibody. The patient improved markedly after initiation of plasmapheresis and has been relapse-free for more than 18 months. The effectiveness of plasmapheresis for treatment of multiple sclerosis in adults is variable and has seldom been reported in children. Our case suggests that plasmapheresis as an alternative therapy is useful for steroid-dependent or severe types of multiple sclerosis even in childhood, especially when its chronic course is assessed by antinuclear antibody titers.

Ala/Thr60 variant of the Leydig insulin-like hormone is not associated with cryptorchidism in the Japanese population.

Abstract 
 Background : Leydig insulin‐like hormone (Insl3), a member of the insulin‐like superfamily, is specifically expressed in Leydig cells of fetal and postnatal murine testis. Recently, the absence of the Insl3 gene has been reported to result in bilateral cryptorchidism in male mice and it has been suggested that mutations of the INSL3 gene may cause cryptorchidism in humans.

Evidence for the association of ultraviolet-C and H2O2-induced apoptosis with acid sphingomyelinase activation

Ceramide appears to be a potent second messenger implicated in the regulation of diverse cellular processes such as cell growth and differentiation, gene transcription, ligand binding, and cell death. Environmental stress-induced apoptosis is believed to be associated with the sphingomyelin degradation pathway, which generates ceramide as a second messenger in initiating the apoptosis response. To date, two distinct sphingomyelinases, a lysosomal acid sphingomyelinase (ASM), which is deficient in patients affected with types A and B Niemann-Pick disease (NPD), and a neutral, magnesium-dependent sphingomyelinase (NSM), are candidate enzymes which respond to apoptotic stimulations and cause sphingomyelin hydrolysis and subsequent ceramide generation. Using Epstein-Barr virus (EBV)-transformed lymphoblast cells from type A NPD patient which have defined splicing site mutation in the ASM gene, we showed that ASM-deficient cells were defective in ultraviolet-C (UV-C) and hydrogen peroxide (H(2)O(2)) induced apoptosis. As another induction of apoptosis, we exposed this cell line to serum starvation which influences to p53 expression and leads to apoptosis. There were no differences by the degree of apoptosis between ASM-deficient lymphoblast cells and normal lymphoblast cells. These results are evidence that ASM plays one of the important roles in apoptosis induction by UV-C and H(2)O(2).

Elevated sphingomyelinase and hypercytokinemia in hemophagocytic lymphohistiocytosis.

Purpose Ceramide generated from sphingomyelinase activation has been reported to play a role in cytokine-mediated events. Secretory sphingomyelinase (S-SMase), a product of the acid sphingomyelinase gene, has been found to be derived from many cell types and to exist in human serum. The purpose of the current study was to investigate the serum level of S-SMase. Patients and Methods Three patients with hypercytokinemia caused by hemophagocytic lymphohistiocytosis (HLH) were studied. Serum samples were collected from the three patients with HLH, patients with a deficiency of acid sphingomyelinase, or type B Niemann-Pick disease, and normal controls. The S-SMase activities were determined using 14C-sphingomyelin as a substrate. Results The serum S-SMase activities were increased 10-to 20-fold in the sera from the three patients with HLH (P < 0.0001). The high S-SMase activity was decreased to the normal level along with the clinical improvement of HLH. Conclusions Increased release of S-SMase from cells into the circulation is observed in patients with active HLH. The authors suggest that S-SMase is related to the pathophysiology of hypercytokinemia.

A case of tubulo-interstitial nephritis with exfoliative dermatitis and hepatitis due to phenobarbital hypersensitivity

Severe exfoliative dermatitis and liver dysfunction developed in a 5-year-old girl 3 weeks after initiation of phenobarbital therapy. Liver function improved gradually after discontinuation of phenobarbital. During the convalescent stage an initially mild renal dysfunction was exacerbated by episodes of post-transfusion haemolysis. Liver biopsy revealed moderate parenchymal damage with subacute cellular infiltration. Renal biopsy demonstrated the cardinal findings of interstitial nephritis, excluding the possibility of acute tubular necrosis caused by haemolysis. Serial lymphocyte transformation studies and skin patch tests gave positive results for phenobarbital, supporting the view that these were unusual complications of phenobarbital hypersensitivity.

Combined linkage analysis and exome sequencing identifies novel genes for familial goiter

Familial goiter is a genetic disease showing heterogeneous expression. To identify causative genes, we investigated three multigenerational goiter families with an autosomal dominant inheritance pattern. We performed genome-wide linkage analysis on all the families, combined with whole-exome sequencing in two affected individuals from each family. For linkage analysis, we considered loci with logarithm of odds (LOD) scores >1.5 as candidate regions for identification of rare variants. In one of the families, we found two rare heterozygous missense variants, p.V56M in RGS12 and p.G37D in GRPEL1, which segregate with goiter and are both located within the same haplotype on 4p16. This haplotype was not observed in 150 controls. In the other two families, we identified two additional rare missense variants segregating with goiter, p.A551T in CLIC6 on 21q22.12 and p.V412A in WFS1 on 4p16. In controls, the minor allele frequency (MAF) of p.V412A in WFS1 was 0.017 while p.A551T in CLIC6 was not detected. All identified genes (RGS12, GRPEL1, CLIC6 and WFS1) show expression in the human thyroid gland, suggesting that they may play a role in thyroid gland function. Moreover, these four genes are novel with regard to their involvement in familial goiter, supporting genetic heterogeneity of this disease.

A case report of pediatric fulminant hepatitis treated with plasma diafiltration.

Abstract:  Plasma diafiltration (PDF) is blood purification therapy in which simple plasma exchange is performed with a membrane plasma separator while dialysate flows outside the hollow fibers. A 14‐year‐old boy with fulminant hepatitis underwent two sessions of PDF and one session of hemodiafiltration. We infused filtered replacement fluid for artificial kidneys at a dialysate flow rate of 600 mL/h and a replacement flow rate of 450 mL/h. We infused fresh frozen plasma (1200 mL) and 25% albumin solution (50 mL) intravenously over 8 h. Each PDF session lasted 8 h. The patients total bilirubin, interleukin‐18, and cystatin C levels decreased with treatment, and he recovered from hepatic failure. PDF may be an extremely useful blood purification therapy for pediatric fulminant hepatitis in terms of both medical economics and cytokine removal.

Prolonged activation of the hypothalamus– pituitary–gonadal axis in a child with X‐linked adrenal hypoplasia congenita

X‐linked adrenal hypoplasia congenita (AHC) is a rare developmental disorder of the human adrenal cortex that is caused by a mutation of the DAX‐1 gene, a member of the nuclear hormone receptor superfamily. Hypogonadotrophic hypogonadism is frequently associated with this disease and the DAX‐1 mutation is known to impair gonadotrophin production by acting at both the hypothalamic and pituitary levels. However, three recent studies reported that the hypothalamic–pituitary–gonadal axis was active in six infants with AHC, suggesting that a difference exists in the central regulation of hypothalamic–pituitary–gonadal activity between infant boys and pubertal boys. To determine the effect of the DAX‐1 gene mutation on the axis in early childhood, we measured testosterone, LH, and FSH and performed LH‐releasing hormone tests on a boy with AHC from birth to 3 years of age. Surprisingly, our findings showed that the axis was active from the infantile period to 3 years of age. This delayed initiation of the prepubertal pause, or prolonged activation of the axis, indicates that the DAX‐1 gene is related to the control mechanism of the prepubertal restraint of gonadotrophin secretion.

Detection of neoplastic clone in the hypoplastic and recovery phases preceding acute lymphoblastic leukemia by in vitro amplification of rearranged T-cell receptor delta chain gene.

This study assessed the clonality of hypoplastic and subsequent recovery phases before the development of overt leukemia by molecular genetic analysis. We describe a boy who had transient granulocytopenia and anemia before the development of acute lymphoblastic leukemia (ALL). Initially, his bone marrow was hypocellular with 23.6% of lymphoblastic cells, whereas subsequent marrow after the administration of granulocyte colony-stimulating factor (G-CSF) appeared almost normal without any lymphoblasts. At diagnosis, we found the rearrangement of T cell receptor (TCR) delta gene in the leukemic cell DNA by Southern blot hybridization. The junctional sequence of the V delta 2-D delta 3 recombination of leukemic cells obtained by polymerase chain reaction (PCR) was used for a clonospecific probe. Using the probe, the presence of leukemic clone in the materials before and after diagnosis was examined. We found that the clonospecific probe could detect one leukemic cell in 10,000 normal cells, and we demonstrated the presence of the leukemic clone at the initial hypoplastic and the subsequent recovery phase. The PCR method is very useful to confirm the presence of leukemic clone even in a retrospective analysis using low-quality materials and may be helpful to understand the pathogenesis of a smoldering preleukemic phase.