Satoru Morikawa

Kobe University, Kōbe, Hyōgo, Japan

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Publications (25)65.8 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by deletion or intragenic mutation of SMN1. SMA is classified into several subtypes based on clinical severity. It has been reported that the copy number of SMN2, a highly homologous gene to SMN1, is associated with clinical severity among SMA patients with homozygous deletion of SMN1. The purpose of this study was to clarify the genotype-phenotype relationship among the patients without homozygous deletion of SMN1. Methods: We performed molecular genetic analyses of SMN1 and SMN2 in 112 Japanese patients diagnosed as having SMA based on the clinical findings. For the patients retaining SMN1, the PCR or RT-PCR products of SMN1 were sequenced to identify the mutation. Results: Out of the 112 patients, 106 patients were homozygous for deletion of SMN1, and six patients were compound heterozygous for deletion of one SMN1 allele and intragenic mutation in the retained SMN1 allele. Four intragenic mutations were identified in the six patients: p.Ala2Val, p.Trp92Ser, p.Thr274TyrfsX32 and p.Tyr277Cys. To the best of our knowledge, all mutations except p.Trp92Ser were novel mutations which had never been previously reported. According to our observation, clinical severity of the six patients was determined by the type and location of the mutation rather than SMN2 copy number. Conclusion: SMN2 copy number is not always associated with clinical severity of SMA patients, especially SMA patients retaining one SMN1 allele.
    Brain & development 12/2013; · 1.74 Impact Factor
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    ABSTRACT: Spinal muscular atrophy (SMA) is a common neuromuscular disorder with autosomal recessive inheritance, resulting in the degeneration of motor neurons. The incidence of the disease has been estimated at 1 in 6000-10,000 newborns with a carrier frequency of 1 in 40-60. SMA is caused by mutations of the SMN1 gene, located on chromosome 5q13. The gene product, survival motor neuron (SMN) plays critical roles in a variety of cellular activities. SMN2, a homologue of SMN1, is retained in all SMA patients and generates low levels of SMN, but does not compensate for the mutated SMN1. Genetic analysis demonstrates the presence of homozygous deletion of SMN1 in most patients, and allows screening of heterozygous carriers in affected families. Considering high incidence of carrier frequency in SMA, population-wide newborn and carrier screening has been proposed. Although no effective treatment is currently available, some treatment strategies have already been developed based on the molecular pathophysiology of this disease. Current treatment strategies can be classified into three major groups: SMN2-targeting, SMN1-introduction, and non-SMN targeting. Here, we provide a comprehensive and up-to-date review integrating advances in molecular pathophysiology and diagnostic testing with therapeutic developments for this disease including promising candidates from recent clinical trials.
    Annals of Human Genetics 07/2013; · 2.22 Impact Factor
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    ABSTRACT: We report a newborn with intestinal malrotation who developed a severely high serum unbound bilirubin level and a low serum albumin level without a marked increase in serum total bilirubin level after abdominal surgery, which required exchange transfusion and albumin supplementation. The serum unbound bilirubin level may be highly relative to the serum total bilirubin level in newborns who have undergone abdominal surgery soon after birth and are hypoalbuminemic after surgery.
    Pediatrics International 06/2013; 55(3):e59-62. · 0.88 Impact Factor
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    ABSTRACT: Minimal residual disease (MRD) is derived from tumor-initiating cells (TICs) and is responsible for tumor relapse. Neuroblastoma is characterized by extreme tumor heterogeneity, and more than half of high-risk patients experience tumor relapse. To overcome tumor heterogeneity and achieve more sensitive detection of MRD, several sets of real-time RT-PCR markers have been reported for MRD monitoring in neuroblastoma patients from different centers. However, these markers vary across centers and are still being validated. In the present study, we validated the ability of 14 commonly used real-time RT-PCR markers to detect MRD based on their expression in neuroblastoma TICs, and we developed a novel MRD detection protocol, which scored the samples as MRD-positive when the expression of one of the 11 real-time RT-PCR markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) exceeded the normal range. By using this protocol, we prospectively monitored MRD in 73 bone marrow (BM), 12 peripheral blood stem cell and 8 peripheral blood samples from 14 neuroblastoma patients treated at a single center. We scored 100, 56, 56 and 57% BM cytology-positive, elevated vanillylmandelic acid (VMA), elevated homovanillic acid (HVA) and elevated neuron-specific enolase (NSE) samples as MRD-positive, respectively. MRD was also positive in 48, 45, 46 and 43% of the BM cytology-negative and normal VMA, normal HVA and normal NSE samples, respectively. These results suggest that the present MRD detection protocol based on the expression of a set of 11 real-time RT-PCR markers in neuroblastoma TICs achieves sensitive MRD monitoring in neuroblastoma patients.
    Oncology Reports 04/2013; 29(4):1629-36. · 2.30 Impact Factor
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    ABSTRACT: BACKGROUND: Infants with congenital cytomegalovirus infection (CCMVI) may develop brain abnormalities such as ventricular dilatation, which may potentially associate with sensorineural hearing loss. There is currently no recognized method for quantitative evaluation of ventricle size in infants with CCMVI. Our objectives were to establish a method for quantitative evaluation of ventricle size using computed tomography (CT) in infants with CCMVI, and determine a cut-off value associated with abnormal auditory brainstem response (ABR) early in life. DESIGN/SUBJECTS: This study enrolled 19 infants with CCMVI and 21 non-infected newborn infants as a control group. Infants with CCMVI were divided into two subgroups according to ABR at the time of initial examination: normal ABR (11 infants) or abnormal ABR (8 infants). Ventricle size was assessed by calculating Evans' index (EI) and lateral ventricle width/hemispheric width (LVW/HW) ratio on brain CT images, and was compared among groups. A cut-off ventricle size associated with abnormal ABR was determined. RESULTS: EI and LVW/HW ratio were significantly higher in the CCMVI with abnormal ABR group than the control and CCMVI with normal ABR groups. Cut-off values of 0.26 for EI and 0.28 for LVW/HW ratio had a sensitivity of 100% and 100%, respectively, and a specificity of 73% and 91%, respectively, for association with abnormal ABR. CONCLUSIONS: We established a method for quantitative evaluation of ventricle size using EI and LVW/HW ratio on brain CT images in infants with CCMVI. LVW/HW ratio had a more association with abnormal ABR in the early postnatal period than EI.
    Brain & development 01/2013; · 1.74 Impact Factor
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    ABSTRACT: The patient was an 8-year-old Japanese girl with Gilbert's syndrome (GS). Based on the DNA analysis, she was homozygous for a T-to-G transversion at nucleotide position 1456 in the UGT1A1 gene, leading to the substitution of aspartate for tyrosine at position 486 of the UGT1A1 enzyme. Because this mutation is located in an exon common to UGT1A genes, all the UGT1A enzymes may be affected. It is well-known that UGT1A1, UGT1A6 and UGT1A9 enzymes glucuronidate acetaminophen. To evaluate acetaminophen tolerance in the patient, serum acetaminophen levels were determined after oral administration of acetaminophen (15 mg/kg). The maximum serum acetaminophen level reached (12.8 µg/mL) was far below the toxic level. The finding suggested that the usual therapeutic dose of acetaminophen is safe for the GS patient. The combination of mutation analysis in UGT1A1 and acetaminophen loading test may be useful to avoid adverse effect in GS patients.
    Pediatrics International 12/2012; 54(6):934-6. · 0.88 Impact Factor
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    ABSTRACT: BACKGROUND: Serum unbound bilirubin (UB) level measures bilirubin not bound to albumin, and has been reported to be better than total bilirubin level at identifying infants at risk of developing bilirubin-induced neurotoxicity, including auditory abnormalities. A detailed treatment strategy for newborns with high serum UB levels has not been established. Our objective was to assess auditory outcomes in newborns with serum UB levels of ≥1.00 μg/dL who were treated according to our novel treatment protocol. METHODS: A prospective clinical study was conducted in newborns weighing >1,500 g with serum UB levels of ≥1.00 μg/dL who were admitted to Kobe University Hospital and Kakogawa Municipal Hospital, Japan from 2006 to 2011. Enrolled newborns were treated as follows: (1) if the serum UB level was 1.00-1.50 μg/dL, phototherapy and infusion were administered with or without albumin or immunoglobulin therapy; and (2) if the serum UB level was >1.50 μg/dL, exchange transfusion was performed immediately. Auditory brainstem responses were evaluated at the time of discharge. RESULTS: A total of 89 Japanese newborns with UB levels of ≥1.00 μg/dL were enrolled at a median age of 4 days. Of these, 85 had UB levels of 1.00-1.50 μg/dL and four had UB levels of >1.50 μg/dL. After being treated according to our protocol, no newborns were diagnosed with auditory brainstem response abnormalities. CONCLUSIONS: Our treatment protocol for Japanese newborns with serum UB levels of ≥1.00 μg/dL may be useful for the prevention of bilirubin-induced auditory abnormalities.
    Pediatrics International 09/2012; · 0.88 Impact Factor
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    ABSTRACT: Recent Japanese epidemiology of neonatal sepsis and its predominant pathogens has not been reported. It is also unknown whether there are center differences in the incidence of neonatal sepsis, including early-onset sepsis (EOS) and late-onset sepsis (LOS) in Japan. To investigate the morbidity and characteristics of neonatal sepsis in recent years and the differences in the incidence of sepsis among Japanese neonatal care units. We retrospectively collected the data of newborn infants with culture-proven sepsis that occurred in five Japanese centers of perinatal care from 2006 to 2008. The incidence of sepsis was calculated, including EOS and LOS, and compared among centers. Morbidity from sepsis occurred in 51/6,894 (0.74%) infants. The incidence of EOS and LOS was 0.13 and 0.61%, respectively. The incidence of total sepsis and LOS in infants <1,000 g of birth weight was significantly higher than that in infants who weighed >1,000 g at birth, whereas there were no significant differences in the incidence of EOS between the different birth weights. Methicillin-resistant Staphylococcus aureus was the most common pathogen involved in morbidity and mortality of neonatal sepsis. Significant center differences were observed in the incidence of LOS, but not EOS. The majority of culture-proven neonatal sepsis is LOS, which differs among centers, especially in infants who weigh <1,000 g at birth in Japan. We consider that it is important to control nosocomial infection in newborn care units to further reduce the morbidity of neonatal sepsis in Japan.
    Neonatology 05/2012; 102(1):75-80. · 2.57 Impact Factor
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    ABSTRACT: Background:  Paramyotonia congenita (PMC) is an autosomal dominant disorder characterized by cold- or exercise-induced myotonia. PMC is caused by a mutation in SCN4A which encodes the α-subunit of the skeletal muscle sodium channel. Methods:  The patient was an 11-year-old Japanese girl who was diagnosed as having PMC. To confirm the diagnosis, an orbital ice-pack test and blinking tests were performed. Next, to identify the mutation, genetic analysis of SCN4A was performed. Finally, to evaluate the mutation effect on the protein structure, in silico protein modeling analysis was performed. Results:  Cold- and exercise-induced myotonia was reproduced in the patient with non-invasive bedside tests: ice-pack and blinking tests. In the genetic analysis, a missense mutation, c.4343G>A in SCN4A, was identified, which may result in an arginine to histidine substitution at 1448 in the protein sequence (p.Arg1448His). According to the protein modeling analysis, the mutation neutralized the positive electrostatic charge at 1448 in the DIV/S4 segment and disrupted the beginning of the helical structure in the DIV/S3-S4 linker of the SCN4A protein. Conclusions:  Diagnostic physical interventions in the patient confirmed the phenotype presentation consistent with PMC, and the in silico protein modeling analysis of p.Arg1448His predicted structural changes which can affect function of the protein. All the data confirmed the diagnosis of PMC in the patient and added to existing literature emphasizing the important role of arginine residue at 1448.
    Pediatrics International 04/2012; 54(5):602-612. · 0.88 Impact Factor
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    ABSTRACT: Neuroblastoma is an aggressive pediatric tumor that accounts for 15% of cancer-related deaths in children. More than half of high-risk neuroblastoma patients develop tumor relapse that is lethal in most cases. A small population of tumor-initiating cells (TICs), recently identified from high-risk neuroblastoma patients as spheres, is believed to be responsible for tumor relapse. Rab family small G proteins are essential in controlling membrane traffic and their misregulation results in several cancers. Rab15 was originally isolated as a brain-specific Rab protein regulating the endocytic recycling pathway and was recently identified as a downstream target of the neural transcription factor Atoh1. Previously, we identified two alternatively spliced Rab15 isoforms in neuroblastoma cells and showed a significant correlation between Rab15 expression and neuronal differentiation. As aberrant alternative splicing is intimately associated with an increasing number of cancers, its use as a new diagnostic and/or prognostic biomarker has attracted considerable attention. In the present study, we explored cancer-associated changes of Rab15 alternative splicing in neuroblastoma TICs. We found that Rab15 alternative splicing generated two novel isoforms designated as Rab15(AN2) and Rab15(AN3) in addition to two known isoforms designated as Rab15(CN) and Rab15(AN1). Although both Rab15(AN2) and Rab15(AN3) contained premature termination codons, they were detected in not only neuroblastoma cells but also in normal human tissues. One isoform was predominantly expressed in the brain and testis, while the other isoform was more specifically expressed in the brain. In neuroblastoma, Rab15 isoform balance measured by the Rab15(CN)/Rab15(AN1+AN2+AN3) ratio was significantly decreased in spheres compared to parental cells. These results suggest that Rab15 alternative splicing may serve as a biomarker to discriminate TICs from non-TICs in neuroblastoma.
    Oncology Reports 03/2012; 27(6):2045-9. · 2.30 Impact Factor
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    ABSTRACT: Free bilirubin concentration (B(f)) is an index for identifying newborns at risk for developing bilirubin-induced neurotoxicity. It has been suggested that B(f) measured by a single peroxidase concentration (B(f-single)) does not equal the equilibrium concentration of B(f), which is confirmed by B(f) at two different peroxidase concentrations (B(f-two)). However, the differences between B(f-single) and B(f-two) are unknown in the serum of term or late-preterm newborn infants. Furthermore, to apply B(f-single) with savings on time and cost to the clinical setting, it is very important for us to clarify the differences between B(f-single) and B(f-two). Forty serum samples were obtained from 21 term or late-preterm newborns who were admitted at Kobe University Hospital. Using a peroxidase method, B(f-single) was measured at one peroxidase concentration, and B(f-two) was determined at two different peroxidase concentrations (the manufacturer's recommended peroxidase concentration and half the manufacturer's recommended peroxidase concentration). To clarify the relationship between B(f-single) and peroxidase concentrations, B(f-single) was measured at five different concentrations of peroxidase reagent. Intra-day and inter-day analyses were performed to assess the precision of B(f-single) and B(f-two). 1/B(f-single) increased as peroxidase concentration increased. B(f-single) was significantly lower than B(f-two) (B(f-single): 0.50 microg/dL [0.13 - 1.22 microg/dL] versus B(f-two): 0.59 microg/dL [0.15 - 1.76 microg/dL], p < 0.001), but B(f-single) was significantly correlated with B(f-two) (r = 0.953, p < 0.0001). Intra-day analysis showed that the CV was 9.7% for B(f-two) and 3.3% for B(f-single), and the inter-day CV was 12.4% for B(f-two) and 3.2% for B(f-single). Although B(f-single) and B(f-two) are not identical, B(f-single) is significantly correlated with B(f-two) and it is more precise than B(f-two) in term or late-preterm newborns.
    Clinical laboratory 01/2012; 58(5-6):507-14. · 0.92 Impact Factor
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    ABSTRACT: Spinal muscular atrophy (SMA) is a common autosomal recessive neuromuscular disorder. It is caused by mutations in the SMN1, and its clinical severity is modified by copy number variations of the SMN2. According to previous studies, deletion of SMN1 exon 7 is the most frequently observed in patients with SMA. Therefore, molecular analyses exploiting this genetic lesion could be beneficial in the diagnosis of SMA. Unfortunately, in many geographical regions, physicians do not have the latest molecular screening technologies at their immediate disposal. Thus, to overcome this issue, we developed an SMA-diagnosing system using dried blood spots (DBS) placed on filter paper to facilitate remote diagnosis. In this study, we validate the applicability of DBS on Flinders Technology Associates (FTA) filter paper for detecting SMN1 exon 7 deletions and copy number variations of SMN1 and SMN2. To detect exon 7 deletions in SMN1, polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis was conducted by using DNA extracted from the DBS on FTA filter paper that had been stored at room temperature for a period of up to 4 years. To determine the copy numbers of SMN1 and SMN2, we carried out SYBR green-based real-time PCR by using the same blood specimens. The results obtained from the DBS on FTA filter paper were in complete concordance with those analyses using fresh blood specimens. This indicates that DBS on filter papers is a reliable method for SMA patient detection and carrier screenings. The SMA-diagnosing system, combined with the mailing of DBS on filter paper, will be beneficial for patients suffering from neuromuscular disorders in areas with limited or no access to diagnostic facilities with molecular capabilities.
    Genetic Testing and Molecular Biomarkers 09/2011; 16(2):123-9. · 1.44 Impact Factor
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    ABSTRACT: To assess renin, aldosterone, human atrial natriuretic peptide (hANP) and brain natriuretic peptide (BNP) levels in cord blood from monochorionic diamniotic (MD) twins with a birthweight (BW) discordance that do not satisfy the criteria of twin-to-twin transfusion syndrome (TTTS). Cord blood samples were obtained from 28 MD twins without TTTS. They were divided into two groups on the basis of BW discordance as follows: large (>7.5%) and small (7.5%). Cord blood renin, aldosterone, hANP and BNP levels were measured. Renin levels in MD twins with a large BW discordance were significantly higher than those in MD twins with a small BW discordance, with no significant differences in aldosterone, hANP and BNP levels. A significant correlation was found between renin levels and BW discordance. Renin is activated in MD twins with a BW discordance of >7.5%, even in non-TTTS.
    Journal of perinatology: official journal of the California Perinatal Association 09/2011; 32(7):514-9. · 1.59 Impact Factor
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    ABSTRACT: A growing number of epidemiological studies have demonstrated that the consumption of green tea inhibits the growth of a variety of cancers. Epigallocatechin gallate (EGCG), the most abundant catechin in green tea, has been shown to have an anti-cancer effect against many cancers. Most cancers are believed to be initiated from and maintained by a small population of tumor-initiating cells (TICs) that are responsible for chemotherapeutic resistance and tumor relapse. In neuroblastoma, an aggressive pediatric tumor that often relapses and has a poor prognosis, TICs were recently identified as spheres grown in a serum-free non-adherent culture used for neural crest stem cell growth. Although EGCG has been reported to induce growth arrest and apoptosis in neuroblastoma cells, its effect on neuroblastoma TICs remains to be defined. Gene expression was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). The effects of EGCG on cell proliferation, apoptosis, and sphere formation were determined by cell counting, propidium iodide staining, and sphere (>100 μm in diameter) counting, respectively. Neuroblastoma BE(2)-C cells showed increased expression of stem cell markers (nanog homeobox [NANOG] and octamer-binding transcription factor 4 [OCT4]), as well as decreased expression of neuronal differentiation markers (Cu(2+)-transporting ATPase alpha polypeptide [ATP7A] and dickkopf homolog 2 [DKK2]) in spheres grown in serum-free non-adherent culture, compared to parental cells grown in conventional culture. Although EGCG induced growth arrest and apoptosis in the parental cells in a dose-dependent manner, it was not effective against spheres. However, EGCG potently inhibited sphere formation in the BE(2)-C cells. The present results suggest that EGCG may inhibit the development of TICs in BE(2)-C cells.
    Environmental Health and Preventive Medicine 09/2011; 17(3):246-51.
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    ABSTRACT: The American Academy of Pediatrics guidelines recommend that the total bilirubin (TB)/albumin (Alb) ratio (B/A ratio), instead of serum concentration of unbound bilirubin (UB), can be used with TB for determining treatment modality for jaundiced newborns ≥ 35 weeks of gestation. It is unknown, however, whether the B/A ratio is actually correlated with serum UB. Four hundred and ninety-seven serum samples were obtained from 209 newborns ≥ 35 weeks of gestation, who were admitted to Kobe University Hospital. Serum UB concentration was measured using the glucose oxidase-peroxidase method. Serum TB and Alb concentrations were measured on spectrophotometry. B/A ratios were calculated and were linearly compared with serum UB. Furthermore, the accuracy of the B/A ratio was evaluated. The B/A ratio was significantly correlated with serum UB concentration. A serum UB concentration of 0.6 µg/dL was in agreement with a B/A ratio of 0.5. For comparison of the number of newborns who had serum UB concentrations ≥ or <0.6 µg/dL and B/A ratios ≥ or <0.5, we found the following characteristics: the concordance rate between serum UB concentrations and the B/A ratio was 94%, sensitivity was 51%, and specificity was 99%. The B/A ratio is significantly correlated with serum UB concentration in newborns ≥ 35 weeks of gestation. The B/A ratio, however, is underestimated when serum UB concentrations are >0.6 µg/dL.
    Pediatrics International 08/2011; 54(1):81-5. · 0.88 Impact Factor
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    ABSTRACT: Neuroblastoma is the most common extracranial solid tumor in children and accounts for 15% of pediatric cancer deaths. Although retinoic acid (RA) is currently used to treat high-risk neuroblastoma patients in the clinic, RA-responsiveness is variable and unpredictable. Since no alterations in the RA-signaling pathway have been found in neuroblastoma cells, molecules correlated with RA-induced differentiation will provide predictive markers of RA-responsiveness for clinical use. The Rab family of small G proteins are key regulators of membrane traffic and play a critical role in cell differentiation and cancer progression. Although an increasing number of cancer-associated alternative splicing events have been identified, alternative splicing of Rab proteins remains to be characterized in neuroblastoma. In the present study, we focused on Rab15 that was originally identified as a brain-specific Rab protein and regulates the endocytic recycling pathway. We identified alternatively spliced Rab15 isoforms designated as Rab15CN and Rab15AN in neuroblastoma cells. Rab15CN was composed of 7 exons encoding 212 amino acids and showed brain-specific expression. Alternative splicing of exon 4 generated Rab15AN that was predicted to encode 208 amino acids and was predominantly expressed in testis. RA induced neuronal differentiation of neuroblastoma BE(2)-C cells and specifically up-regulated Rab15CN expression. Reciprocally, RA-induced differentiation was observed in Rab15CN-expressing BE(2)-C cells in preference to Rab15AN-expressing BE(2)-C cells. Furthermore, Rab15CN expression was also specifically up-regulated during RA-induced differentiation of newly established neuroblastoma cells from high-risk patients. These results suggest that Rab15 expression correlates with RA-induced differentiation of neuroblastoma cells.
    Oncology Reports 07/2011; 26(1):145-51. · 2.30 Impact Factor
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    ABSTRACT: Spinal muscular atrophy (SMA) is a well-defined autosomal recessive neuromuscular disorder caused by mutations in the survival motor neuron 1 (SMN1) gene. The most frequently observed mutation is a deletion of exon 7, which has been documented in >95% of SMA patients. A novel technique for detecting mutations known as high-resolution melting analysis (HRMA) has rapidly become the tool of choice for screening pathogenic genetic variants. In the present study, we attempt to validate the applicability of HRMA to the detection of exon 7 deletions and other intragenic mutations in SMN1. Three primer sets were adopted in our HRMA screening for deletion of SMN1 exon 7. In screening attempts utilizing two primer sets, the results of HRMA were not compatible with those obtained by polymerase chain reaction-restriction fragment length polymorphism. Therefore, we applied a modified protocol using revised primer sets, which resulted in an absolute compatibility of results between HRMA and polymerase chain reaction-restriction fragment length polymorphism. With regard to screenings for intragenic mutations in SMN1 exon 3, two primer sets were adopted for use in HRMA. In the initial HRMA screening using the first primer set, we failed to identify any intragenic mutations; however, when using a revised primer set, HRMA successfully detected the presence of a c.275G>C mutation. HRMA is a simple but versatile tool to add to the existing arsenal of diagnostic techniques that could aid clinicians/researchers in diagnosing SMA. However, as we demonstrate in the present study, the design and selection of primers is of monumental importance in ensuring the successful application of HRMA to screening for pathogenic variants.
    Genetic Testing and Molecular Biomarkers 06/2011; 15(10):677-84. · 1.44 Impact Factor
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    ABSTRACT: Spinal muscular atrophy (SMA) is a common autosomal recessive neuromuscular disorder that is caused by loss of the survival motor neuron gene, SMN1. SMA treatment strategies have focused on production of the SMN protein from the almost identical gene, SMN2. Valproic acid (VPA) is a histone deacetylase inhibitor that can increase SMN levels in some SMA cells or SMA patients through activation of SMN2 transcription or splicing correction of SMN2 exon 7. It remains to be clarified what concentration of VPA is required and by what mechanisms the SMN production from SMN2 is elicited. We observed that in two fibroblast cell lines from Japanese SMA patients, more than 1mM of VPA increased SMN2 expression at both the transcript and protein levels. VPA increased not only full-length (FL) transcript level but also exon 7-excluding (Δ7) transcript level in the cell lines and did not change the ratio of FL/Δ7, suggesting that SMN2 transcription was mainly activated. We also found that VPA modulated splicing factor expression: VPA increased the expression of splicing factor 2/alternative splicing factor (SF2/ASF) and decreased the expression of heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1). In conclusion, more than 1mM of VPA activated SMN2 transcription and modulated the expression of splicing factors in our SMA fibroblast cell lines.
    Brain & development 05/2011; 34(3):213-22. · 1.74 Impact Factor
  • Nature medicine 01/2011; 17(1):29-30; author reply 30-1. · 27.14 Impact Factor
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    ABSTRACT: The UGT1A1 gene encodes a responsible enzyme, UDP-glucuronosyltransferase1A1, for bilirubin metabolism. Many mutations have already been identified in patients with inherited disorders with hyperbilirubinemia, Crigler-Najjar syndrome and Gilbert's syndrome. In this study, we identified a UGT1A1 mutation in an 8-year-old Japanese girl with persistent hyperbilirubinemia who was clinically diagnosed as having Gilbert's syndrome. For the mutational analysis of UGT1A1, we performed a full sequence analysis of the gene using the patient's DNA. She was homozygous for a T to G transversion at nucleotide position 1456 in UGT1A1 exon 5 (c.1456T>G), leading to the substitution of aspartate for tyrosine at position 486 of the UGT1A1 protein (p.Y486D). In conclusion, the homozygous mutation of UGT1A1 may be responsible for persistent hyperbilirubinemia in this patient.
    The Kobe journal of medical sciences 01/2011; 57(1):E26-31.