Distinct Expression Profiles of Neuroblastoma-Associated mRNAs in Peripheral Blood and Bone Marrow of Non-High-Risk and High-Risk Neuroblastoma Patients.

Non-high-risk (non-HR) neuroblastoma (NB) patients have excellent outcomes, with more than a 90% survival rate, whereas HR NB patients expect less than a 50% survival rate. Metastatic disease is the principal cause of death among both non-HR and HR NB patients. Previous studies have reported the significant but limited prognostic value of quantitative PCR (qPCR)-based assays, measuring overlapping but different sets of neuroblastoma-associated mRNAs (NB-mRNAs), to detect metastatic disease in both non-HR and HR patient samples. A droplet digital PCR (ddPCR)-based assay measuring seven NB-mRNAs (CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNAs) was recently developed and exhibited a better prognostic value for HR patient samples than qPCR-based assays. However, it remained to be tested on non-HR patient samples. In the present study, we employed the ddPCR-based assay to study peripheral blood (PB) and bone marrow (BM) samples collected at diagnosis from eight non-HR and eleven HR cases and characterized the expression profiles of NB-mRNAs. The most highly expressed NB-mRNAs in PB and BM differed between non-HR and HR cases, with the CRMP1 mRNA being predominant in non-HR cases and the GAP43 mRNA in HR cases. The levels of NB-mRNAs in PB and BM were 5 to 1000 times lower in non-HR cases than in HR cases. The PB to BM ratio of NB-mRNAs was 10 to 100 times higher in non-HR cases compared to HR cases. The present case series suggests that non-HR and HR NB patients have the distinct expression profiles of NB-mRNAs in their PB and BM.

Impact of prophylactic echinocandin on the development of neurological complications in patients receiving busulfan-containing conditioning regimens for stem cell transplantation: A single-center retrospective study.

BACKGROUND: Although neurotoxicity is a major adverse event associated with busulfan, little information is available regarding the association between drug interactions and neurological symptoms during busulfan-based regimens. This study evaluated the association between prophylactic echinocandins and neurological complications in patients receiving busulfan-containing conditioning regimens for stem cell transplantation. METHODS: We retrospectively included consecutive patients who administered intravenous busulfan as a conditioning regimen at our facility between 2007 and 2022. Prophylactic echinocandin use was defined as the use of an echinocandin antifungal drug to prevent invasive fungal disease in SCT recipients. The primary outcome was the incidence of neurological complications within 7 days of busulfan initiation and was compared between the echinocandin group (patients received prophylactic echinocandin) and nonechinocandin group (patients received prophylactic antifungal drugs other than echinocandin and those without antifungal prophylaxis). RESULTS: Among the 59 patients included in this study, the incidence of neurological complications in the echinocandin (n = 26) and nonechinocandin groups (n = 33) was 30.8% and 63.6%, respectively. We observed a negative association between prophylactic echinocandin use and the development of neurological complications after adjusting for the propensity score for receiving prophylactic echinocandins (adjusted odds ratio 0.294, 95% confidence interval 0.090 to 0.959). We observed a lower incidence of neurological complications in the echinocandin group than in the nonechinocandin group. CONCLUSION: Our results suggested that the choice of antifungal prophylaxis is associated with busulfan neurotoxicity.

A novel NFKB1 variant in a Japanese pedigree with common variable immunodeficiency.

Recently, heterozygous loss-of-function NFKB1 variants were identified as the primary cause of common variable immunodeficiency (CVID) in the European population. However, pathogenic NFKB1 variants have never been reported in the Japanese population. We present a 29-year-old Japanese woman with CVID. A novel variant, c.136 C > T, p.(Gln46*), was identified in NFKB1. Her mother and daughter carried the same variant, demonstrating the first Japanese pedigree with an NFKB1 pathogenic variant.

Higher levels of minimal residual disease in peripheral blood than bone marrow before 1st and 2nd relapse/regrowth in a patient with high­risk neuroblastoma: A case report.

More than half of patients with high-risk neuroblastoma (HR-NB) experience relapse/regrowth due to the activation of chemoresistant minimal residual disease (MRD). MRD in patients with HR-NB can be evaluated by quantitating neuroblastoma-associated mRNAs (NB-mRNAs) in bone marrow (BM) and peripheral blood (PB) samples. Although several sets of NB-mRNAs have been shown to possess a prognostic value for MRD in BM samples (BM-MRD), MRD in PB samples (PB-MRD) is considered to be low and difficult to evaluate. The present report describes an HR-NB case presenting higher PB-MRD than BM-MRD before 1st and 2nd relapse/regrowth. A 3-year-old female presented with an abdominal mass, was diagnosed with HR-NB, and treated according to the nationwide standard protocol for HR-NB. Following systemic induction and consolidation therapy with local therapy, the patient achieved complete remission but experienced a 1st relapse/regrowth 6 months after maintenance therapy. The patient partially responded to salvage chemotherapy and anti-GD2 immunotherapy but had a 2nd relapse/regrowth 14 months after the 1st relapse/regrowth. Consecutive PB-MRD and BM-MRD monitoring revealed that PB-MRD was lower than BM-MRD at diagnosis (100 times) and 1st and 2nd relapse/regrowth (1,000 and 3 times) but became higher than BM-MRD before 1st and 2nd relapse/regrowth. The present case highlights that PB-MRD can become higher than BM-MRD before relapse/regrowth of patients with HR-NB.

Association between conditioning intensity and height growth after allogeneic hematopoietic stem cell transplantation in children.

BACKGROUND: The present study aimed to examine the association between the conditioning intensity and height growth in pediatric patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: We reviewed the clinical records of 89 children with malignant diseases who underwent initial allo-HSCT between 2003 and 2021. Height measurements were standardized using standard height charts prepared by the Japanese Society for Pediatric Endocrinology to calculate standard deviation score (SDS). We defined short stature as a height SDS less than -2.0 in that reference. Myeloablative conditioning (MAC) comprised total-body irradiation at more than 8 Gy and busulfan administration at more than 8 mg/kg (more than 280 mg/m2 ). Other conditioning regimens were defined as reduced intensity conditioning (RIC). RESULTS: A total of 58 patients underwent allo-HSCT with MAC, and 31 patients received allo-HSCT with RIC. There were significant differences in the height SDS at 2 and 3 years after allo-HSCT between MAC and RIC group (-1.33 ± 1.20 vs. -0.76 ± 1.12, p = 0.047, -1.55 ± 1.28 vs. -0.75 ± 1.11, p = 0.022, respectively). Multivariate logistic regression analysis with the adjustments for potential confounding factors of patients less than 10 years of age at allo-HSCT and chronic graft-versus host disease demonstrated that MAC regimen was associated with a markedly increased risk of a short stature at 3 years after allo-HSCT (adjusted odds ratio, 5.61; 95% confidence interval, 1.07-29.4; p = 0.041). CONCLUSION: The intensity of conditioning regimen may be associated with short statures after allo-HSCT.

Nosocomial meningitis caused by Staphylococcus haemolyticus in a child with neutropenia in the absence of intracranial devices: a case report.

BACKGROUND: Coagulase-negative staphylococci can cause hospital-acquired infections, especially in immunocompromised hosts. Bacterial meningitis is a potentially fatal infection of the central nervous system, causing high mortality and morbidity. In general, the causative agents of meningitis, coagulase-negative staphylococci, are associated with direct implantation of a foreign body and the presence of a cerebrospinal fluid (CSF) shunt. Here, we describe a case of nosocomial meningitis caused by Staphylococcus haemolyticus in a child with neutropenia who had no intracranial foreign devices. CASE PRESENTATION: A 15-year-old boy with relapsed acute myeloid leukemia undergoing chemotherapy through a central venous catheter developed fever on Day 13 post-initiation of chemotherapy. There was no history of implantation of neurosurgical devices. Two blood cultures obtained on Day 14 were positive for Staphylococcus haemolyticus. Clinical improvement was noted, and treatment with vancomycin and removal of the central venous catheter resulted in negative repeat blood cultures on Day 18. However, the patient developed a tendency for somnolence and improper speech, along with persistent fever on Day 26. A lumber puncture was performed on Day 27, resulting in positive culture of Staphylococcus haemolyticus. He was diagnosed with meningitis and the dosage of vancomycin was increased. A repeat CSF culture was positive for Staphylococcus haemolyticus on Day 40, so oral rifampicin was added. CSF findings on Day 46 revealed a low concentration of vancomycin, and treatment was switched from vancomycin plus rifampicin to linezolid. After Day 46, four subsequent cerebrospinal fluid tests of the CSF showed no growth of Staphylococcus haemolyticus. The patient's symptoms were improved on Day 52. Brain and spinal magnetic resonance images was taken and it showed no abnormalities. Linezolid was continued until Day 72. The patient was discharged without any complications on Day 72. CONCLUSIONS: To the best of our knowledge, this is the first reported case of Staphylococcus haemolyticus meningitis in a patient without a neurosurgical device. Typical symptoms or signs may be absent in a patient with meningitis who also has neutropenia. Repeated tests of the CSF, and prolonged duration of antibiotics should be considered if atypical pathogens are detected in immunocompromised hosts.

Epidural Spinal Cord Compression as the Presenting Manifestation of Acute Myeloid Leukemia: A Case Report and Literature Review.

We herein report a rare case of spinal cord compression due to epidural involvement of acute myeloid leukemia (AML). A 14-year-old boy presented with a 7-day history of back pain, paraplegia and hypoesthesia. Contrast-enhanced computed tomography revealed an epidural mass. Emergency laminectomy and resection of the mass were performed. Histopathologically, the resected mass was comparable to an extramedullary mass of AML. Chemotherapy was initiated, and complete remission was achieved. Neurological sequelae remained after the treatment. Based on the present and previous reports, spinal cord compression from epidural AML involvement may progress rapidly.

Spindle cell sarcoma with KIAA1549-BRAF resembling infantile fibrosarcoma morphologically: A case report and literature review.

Infantile fibrosarcoma (IFS) commonly harbors ETS variant transcription factor 6 (ETV6)-neurotrophic receptor tyrosine kinase 3 (NTRK3) fusion. However, the recent accessibility to clinical next-generation sequencing (NGS) has revealed ETV6-NTRK3 negative spindle cell sarcomas resembling IFS morphologically, involving NTRK1/2, MET, RET and BRAF. The present report describes a pediatric case of spindle cell sarcoma with KIAA1549-BRAF resembling IFS morphologically. A 20-month-old female patient was referred to Kobe Children's Hospital (Kobe, Japan) for the treatment of intrathoracic spindle cell sarcoma. Pathologically, the intrathoracic tumor cells were composed of spindle cells with focal hemagiopericytomatous pattern. In immunohistochemistry analysis, the intrathoracic tumor cells focally expressed desmin and WT-1 and were negative for pan-tropomyosin receptor kinase (TRK), S-100 and CD34. Fluorescence in situ hybridization analysis for ETV6 and capicua transcriptional repressor revealed negative split signals. Although the patient was initially diagnosed with IFS morphologically, KIAA1549-BRAF fusion transcript was detected by comprehensive genomic profiling with NGS using intrathoracic tumor tissues and confirmed by reverse transcription-PCR. Chemotherapy induced a reduction in the tumor size. At present, the patient is alive with the disease and has been receiving therapy for 8 months since the initiation of chemotherapy. Review of BRAF-altered spindle cell sarcomas resembling IFS morphologically revealed the inconsistency in immunohistochemical expression patterns and the diversity of BRAF fusion genes and mutations. Therefore, the elucidation of genomic profiling by NGS may assist in making an appropriate diagnosis and selecting novel alternative therapies in ETV6-NTRK3-negative spindle cell sarcomas resembling IFS morphologically.

Minimal residual disease detected by droplet digital PCR in peripheral blood stem cell grafts has a prognostic impact on high-risk neuroblastoma patients.

More than half of high-risk neuroblastoma (NB) patients have experienced relapse due to the activation of chemoresistant minimal residual disease (MRD) even though they are treated by high-dose chemotherapy with autologous peripheral blood stem cell (PBSC) transplantation. Although MRD in high-risk NB patients can be evaluated by quantitative PCR with several sets of neuroblastoma-associated mRNAs (NB-mRNAs), the prognostic significance of MRD in PBSC grafts (PBSC-MRD) is unclear. In the present study, we collected 20 PBSC grafts from 20 high-risk NB patients and evaluated PBSC-MRD detected by droplet digital PCR (ddPCR) with 7NB-mRNAs (CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNA). PBSC-MRD in 11 relapsed patients was significantly higher than that in 9 non-relapsed patients. Patients with a higher PBSC-MRD had a lower 3-year event-free survival (P = 0.0148). The present study suggests that PBSC-MRD detected by ddPCR with 7NB-mRNAs has a prognostic impact on high-risk NB patients.

Association between muscle mass evaluated by computed tomography and the serum creatinine-cystatin C ratio in children with cancer: A cross-sectional study.

OBJECTIVE: There is limited knowledge about muscle-mass loss in childhood and adolescent patients with cancer. The aim of this study was to investigate the association between muscle mass evaluated by computed tomography (CT) and the serum creatinine-cystatin C ratio (CCR) in children and adolescents with cancer. METHODS: Patients age <18 y with cancer who underwent abdominal CT scans and blood sampling for serum creatinine and cystatin C within 1 wk before or after the CT scan between 2017 and 2019 at our hospital were retrospectively enrolled. A measurement was defined as a set of abdominal CT scans and serum creatinine and cystatin C levels. The psoas muscle cross-sectional area (PMCSA) was defined as the psoas major muscle area at the level of the fourth lumbar vertebra on axial CT. Statistical tests and modeling were performed as measurement-based analyses. RESULTS: A total of 109 patients and 204 measurements were included in the analysis. CCR showed a strong positive correlation with PMCSA (r = 0.75; P < 0.001). The association between CCR and PMCSA was observed in all age groups and both sexes. There was a clear trend of increased PMCSA across quartile categories of CCR (P < 0.001). On multivariate, generalized, estimating, equation, linear regression model analysis, examining factors associated with PMCSA, male sex, body surface area, and CCR were independent parameters for PMCSA. CONCLUSIONS: These results suggest that CCR may be a useful surrogate marker for muscle mass in cancer care for children and adolescents.

The comparison of acute toxicities associated with craniospinal irradiation between photon beam therapy and proton beam therapy in children with brain tumors.

INTRODUCTION: This study aimed to evaluate acute toxicities associated with irradiation between the X-CSI (photon beam craniospinal irradiation) and P-CSI (proton beam craniospinal irradiation) groups in children with brain tumors. METHODS: Sixty-two consecutive patients who received initial craniospinal irradiation (CSI) for brain tumors in our center between January 1, 2011 and May 31, 2021, were included in the study. Acute toxicities were retrospectively evaluated during CSI using Common Terminology Criteria for Adverse Events version 5.0. Maximum grades of fatigue, headache, insomnia, nausea, vomiting, dermatitis, constipation, abdominal pain, oropharyngeal mucositis, and hematological toxicities were evaluated. RESULTS: Thirty-six patients received X-CSI, and 26 patients received P-CSI. The median dose of CSI was 18.0 Gy in the X-CSI group and 23.4 Gy (relative biological effectiveness) in the P-CSI group (p < 0.001). The P-CSI group had a lower incidence of more than grade 2 nausea (11.5% vs. 69.4%, p = 0.008) and vomiting (7.7% vs. 38.8%, p < 0.001), compared with the X-CSI group. Multivariate logistic regression analysis with adjustments for potential confounding factors of doses of CSI showed that proton radiation therapy was associated with a marked reduced risk of more than grade 2 nausea and vomiting during CSI (adjusted odds ratio, 0.050; 95% confidential interval, 0.011-0.24; p < 0.001). CONCLUSION: The present study suggests that P-CSI reduces the acute gastrointestinal toxicities associated with irradiation.

A case of autoimmune enteropathy with CTLA4 haploinsufficiency.

Autoimmune enteropathy (AIE) is a rare disease, characterized by intractable diarrhea, villous atrophy of the small intestine, and the presence of circulating anti-enterocyte autoantibodies. Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, and mutations in FOXP3, which is a master gene of regulatory T cells (Tregs), are major causes of AIE. Recent studies have demonstrated that mutations in other Treg-associated genes, such as CD25 and CTLA4, show an IPEX-like phenotype. We present the case of a 13-year-old girl with CTLA4 haploinsufficiency, suffering from recurrent immune thrombocytopenic purpura and intractable diarrhea. We detected an autoantibody to the AIE-related 75 kDa antigen (AIE-75), a hallmark of the IPEX syndrome, in her serum. She responded well to a medium dose of prednisolone and a controlled dose of 6-mercaptopurine (6-MP), even after the cessation of prednisolone administration. Serum levels of the soluble interleukin-2 receptor and immunoglobulin G (IgG) were useful in monitoring disease activity during 6-MP therapy. In conclusion, autoimmune-mediated mechanisms, similar to the IPEX syndrome, may be involved in the development of enteropathy in CTLA4 haploinsufficiency. Treatment with 6-MP and monitoring of disease activity using serum levels of soluble interleukin-2 receptor and IgG is suggested for such cases.

The incidence of symptomatic osteonecrosis is similar between Japanese children and children in Western countries with acute lymphoblastic leukaemia treated with a Berlin-Frankfurt-Münster (BFM)95-based protocol.

In this study, we performed a retrospective analysis of a cohort of Japanese paediatric patients with B-cell precursor (BCP)-acute lymphoblastic leukaemia (ALL) treated with a Berlin-Frankfurt-Münster (BFM)95-based protocol, to clarify the incidence, clinical characteristics, and risk factors of osteonecrosis (ON) in comparison to the ALL-02 protocol. We identified a high frequency of ON with the BFM95-based protocol compared to the ALL-02 protocol. The incidence of symptomatic ON with the BFM95-based protocol is comparable to previous studies in Western countries. We believe that the type of treatment regimen has more impact on the incidence of symptomatic ON in paediatric ALL than ethnicity.

Effect of Monoammonium Glycyrrhizinate on the Development of Hepatotoxicity After Initial Intrathecal Chemotherapy for Leukemia.

BACKGROUND/AIM: Chemotherapy for acute leukemia includes agents known to cause hepatotoxicity. This study evaluated the role of monoammonium glycyrrhizinate for the prevention of hepatotoxicity after the first methotrexate-containing intrathecal chemotherapy (ITC) in children and adolescents with leukemia. PATIENTS AND METHODS: Patients with newly diagnosed acute leukemia (age 0-18 years) who received ITC during the first week of induction therapy at our hospital between April 2016 and March 2021 were enrolled. Intravenous monoammonium glycyrrhizinate (IVMG) was defined as the intravenous administration of monoammonium glycyrrhizinate initiated on the day before or the day of the first ITC. RESULTS: Overall, 39 of 118 patients (33%) developed grade 3-4 hepatotoxicity. The inverse probability of treatment weighting logistic regression model showed that IVMG was not associated with the development of grade 3-4 hepatotoxicity (OR=1.9, 95%CI=0.808-4.468). CONCLUSION: IVMG did not protect against the development of grade 3-4 hepatotoxicity after the first methotrexate-containing ITC for leukemia.

Microstructure Investigation of Polymer Electrolyte Fuel Cell Catalyst Layers Containing Perfluorosulfonated Ionomer.

Perfluorosulfonated ionomers are the most successful ion-exchange membranes at an industrial scale. One recent, cutting-edge application of perfluorosulfonated ionomers is in polymer electrolyte fuel cells (PEFCs). In PEFCs, the ionomers are used as a component of the catalyst layer (CL) in addition to functioning as a proton-exchange membrane. In this study, the microstructures in the CLs of PEFCs were characterized by combined synchrotron X-ray scattering and transmission electron microscopy (TEM) analyses. The CL comprised a catalyst, a support, and an ionomer. Fractal dimensional analysis of the combined ultrasmall- and small-angle X-ray scattering profiles indicated that the carbon-black-supported Pt catalyst (Pt/CB) surface was covered with the ionomer in the CL. Anomalous X-ray scattering revealed that the Pt catalyst nanoparticles on the carbon surfaces were aggregated in the CLs. These findings are consistent with the ionomer/catalyst microstructures and ionomer coverage on the Pt/CB surface obtained from TEM observations.

Limited correlation between tumor markers and minimal residual disease detected by seven neuroblastoma-associated mRNAs in high-risk neuroblastoma patients.

Vanillylmandelic acid (VMA), homovanillic acid (HVA), neuron-specific enolase (NSE) and lactate dehydrogenase (LDH) are classical tumor markers and are used as standard clinical evaluations for patients with neuroblastoma (NB). Minimal residual disease (MRD) can be monitored by quantifying several sets of NB-associated mRNAs in the bone marrow (BM) and peripheral blood (PB) of patients with NB. Although MRD in BM and PB has been revealed to be a strong prognostic factor that is independent of standard clinical evaluations, its interrelation with tumor markers remains uncharacterized. The present study determined the levels of tumor markers (VMA, HVA, NSE and LDH) and MRD (BM-MRD and PB-MRD) in 133 pairs of concurrently collected BM, PB and urine samples from 19 patients with high-risk NB. The patients were evaluated during the entire course of treatment, which included 10 diagnoses, 32 treatments, 36 post-treatment, 9 relapses and 46 post-relapse sample pairs. The level of BM-MRD and PB-MRD was determined by quantifying 7 NB-mRNAs (collapsin response mediator protein 1, dopamine beta-hydroxylase, dopa decarboxylase, growth-associated protein 43, ISL LIM homeobox 1, pairedlike homeobox 2b and tyrosine hydroxylase) using droplet digital PCR. In overall sample pairs, tumor markers (VMA, HVA, NSE and LDH) demonstrated weak but significant correlations (P<0.011) with BM-MRD and PB-MRD. In subgroups according to each patient evaluation, the degree of correlation between tumor markers and MRD became stronger in patients with adrenal gland tumors, BM metastasis at diagnosis and relapse/regrowth compared with overall sample pairs. In contrast, tumor markers demonstrated variable correlations with MRD in subgroups according to each sample evaluation (BM infiltration at sampling, collection time point and disease status). The results suggested that tumor markers may demonstrate limited correlation with MRD in patients with high-risk NB.

Minimal residual disease in high-risk neuroblastoma shows a dynamic and disease burden-dependent correlation between bone marrow and peripheral blood.

Neuroblastoma (NB) is the most common extracranial solid tumor in children and originates from sympathoadrenal or Schwann cell precursors derived from neural crest. These neural crest derivatives also constitute the hematopoietic and mesenchymal stem cells in bone marrow (BM) that is the most frequent site of NB metastasis and relapse. In NB patients, NB cells have been pathologically detected in BM and peripheral blood (PB), and minimal residual disease (MRD) in BM and PB (BM-MRD and PB-MRD) can be monitored by quantitating several sets of NB-associated mRNAs (NB-mRNAs). Although previous studies have shown varying degrees of correlation between BM-MRD and PB-MRD, the underlying factors and/or mechanisms remains unknown. In the present study, we determined the levels of BM-MRD and PB-MRD by quantitating seven NB-mRNAs in 133 pairs of concurrently collected BM and PB samples from 19 high-risk NB patients with clinical disease evaluation, and examined their correlation in overall and subgroups of sample pairs. The levels of BM-MRD and PB-MRD were moderately (r = 0.418, p < 0.001) correlated with each other in overall sample pairs. The correlation became strong (r = 0.725, p < 0.001), weak (r = 0.284, p = 0.008), and insignificant (p = 0.194) in progression, stable, and remission subgroups of sample pairs, respectively. It also became stronger in subgroups of sample pairs with poor treatment responses and poor prognostic factors. Present study suggests that MRD in high-risk NB shows a dynamic and disease burden-dependent correlation between BM and PB.

Usefulness of functional splicing analysis to confirm precise disease pathogenesis in Diamond-Blackfan anemia caused by intronic variants in RPS19.

Diamond-Blackfan anemia (DBA) is mainly caused by pathogenic variants in ribosomal proteins and 22 responsible genes have been identified to date. The most common causative gene of DBA is RPS19 [NM_001022.4]. Nearly 180 RPS19 variants have been reported, including three deep intronic variants outside the splicing consensus sequence (c.72-92A > G, c.356 + 18G > C, and c.411 + 6G > C). We also identified one case with a c.412-3C > G intronic variant. Without conducting transcript analysis, the pathogenicity of these variants is unknown. However, it is difficult to assess transcripts because of their fragility. In such cases, in vitro functional splicing assays can be used to assess pathogenicity. Here, we report functional splicing analysis results of four RPS19 deep intronic variants identified in our case and in previously reported cases. One splicing consensus variant (c.411 + 1G > A) was also examined as a positive control. Aberrant splicing with a 2-bp insertion between exons 5 and 6 was identified in the patient samples and minigene assay results also identified exon 6 skipping in our case. The exon 6 skipping transcript was confirmed by further evaluation using quantitative RT-PCR. Additionally, minigene assay analysis of three reported deep intronic variants revealed that none of them showed aberrant splicing and that these variants were not considered to be pathogenic. In conclusion, the minigene assay is a useful method for functional splicing analysis of inherited disease.