Characteristics of genetic alterations of peripheral T-cell lymphoma in childhood including identification of novel fusion genes: the Japan Children's Cancer Group (JCCG).

Peripheral T-cell lymphoma (PTCL) is a group of heterogeneous non-Hodgkin lymphomas showing a mature T-cell or natural killer cell phenotype, but its molecular abnormalities in paediatric patients remain unclear. By employing next-generation sequencing and multiplex ligation-dependent probe amplification of tumour samples from 26 patients, we identified somatic alterations in paediatric PTCL including Epstein-Barr virus (EBV)-negative (EBV- ) and EBV-positive (EBV+ ) patients. As recurrent mutational targets for PTCL, we identified several previously unreported genes, including TNS1, ZFHX3, LRP2, NCOA2 and HOXA1, as well as genes previously reported in adult patients, e.g. TET2, CDKN2A, STAT3 and TP53. However, for other reported mutations, VAV1-related abnormalities were absent and mutations of NRAS, GATA3 and JAK3 showed a low frequency in our cohort. Concerning the association of EBV infection, two novel fusion genes: STAG2-AFF2 and ITPR2-FSTL4, and deletion and alteration of CDKN2A/2B, LMO1 and HOXA1 were identified in EBV- PTCL, but not in EBV+ PTCL. Conversely, alterations of PCDHGA4, ADAR, CUL9 and TP53 were identified only in EBV+ PTCL. Our observations suggest a clear difference in the molecular mechanism of onset between paediatric and adult PTCL and a difference in the characteristics of genetic alterations between EBV- and EBV+ paediatric PTCL.

Characteristics of inhomogeneous lower extremity growth and development in early childhood: a cross-sectional study.

BACKGROUND: Early childhood is a transferring stage between the two accelerated growth periods (infant and adolescent). Body dimensions are related to physical growth and development. The purpose of this study was to investigate physical growth in terms of anthropometry, muscle growth of the lower extremity, and functional development over early childhood. METHODS: A cross-sectional study was carried out on 29 preschool children (PS: 3-5 years), 21 school children (SC: 6-8 years), and 22 adults (AD: 20-35 years). Lower extremity characteristics (segmental dimensions, muscle and adipose tissue thicknesses of the thigh and lower leg), and voluntary joint torque (knee and ankle) were measured. Correlations between parameters and group comparisons were performed. RESULTS: All the parameters except for body mass index (BMI) and subcutaneous adipose tissue thickness were correlated with age for PS and SC combined (r = 0.479-0.920, p < 0.01). Relative thigh and shank lengths to body height were greatest in AD and smallest in PS (p < 0.05) but the relative foot dimensions were significantly larger in PS and SC than in AD (p < 0.05). Relative subcutaneous adipose tissue thickness was largest in PS and lowest in AD. Muscle thickness and the muscle volume measure (estimated from muscle thickness and limb length) were significantly larger in older age groups (p < 0.05). All groups showed comparable muscle thickness when normalized to limb length. Joint torque normalized to estimated muscle volume was greatest for AD, followed by SC and PS (p < 0.05). CONCLUSIONS: Relative lower extremity lengths increase with age, except for the foot dimensions. Muscle size increases with age in proportion to the limb length, while relative adiposity decreases. Torque-producing capacity is highly variable in children and rapidly develops toward adulthood. This cross-sectional study suggests that children are not a small scale version of adults, neither morphologically nor functionally.

Inhomogeneous and Anisotropic Mechanical Properties of the Triceps Surae Aponeuroses in Older Adults: Relationships With Muscle Strength and Walking Performance.

This study investigated (a) site- and direction-dependent variations of passive triceps surae aponeurosis stiffness and (b) the relationships between aponeurosis stiffness and muscle strength and walking performance in older individuals. Seventy-nine healthy older adults participated in this study. Shear wave velocities of the triceps surae aponeuroses at different sites and in two orthogonal directions were obtained in a prone position at rest using supersonic shear imaging. The maximal voluntary isometric contraction torque of the plantar flexors and normal (preferred) and fast (fastest possible) walking speeds (5-m distance) were also measured. The shear wave velocities of the adjoining aponeuroses were weakly associated with plantar flexion torque (r = .23-.34), normal (r = .26), and fast walking speed (r = .25). The results show clear spatial variations and anisotropy of the triceps surae aponeuroses stiffness in vivo, and the aponeurosis stiffness was associated with physical ability in older adults.

A Multicenter, Open-label, Clinical Trial to Assess the Effectiveness and Safety of Allogeneic Hematopoietic Stem Cell Transplantation Using Reduced-intensity Conditioning in Relapsed/refractory Anaplastic Large-cell Lymphoma in Children.

No standard treatment for relapsed or refractory anaplastic large-cell lymphoma (ALCL) has been established. This study is a multicenter, open-label trial to examine the effectiveness and safety of transplantation with reduced-intensity conditioning (RIC) for patients under 20 years old with relapsed or refractory ALCL. We defined RIC as the administration of fludarabine (30 mg/m2/day) for five days plus melphalan (70 mg/m2/day) for two days and total body irradiation at 4 Gy, followed by allogeneic hematopoietic stem cell transplantation.

Children and adolescents with marginal zone lymphoma have an excellent prognosis with limited chemotherapy or a watch-and-wait strategy after complete resection.

Data on management of pediatric marginal zone lymphoma (MZL) are scarce. This retrospective study assessed characteristics and outcome in 66 patients who were <18 years old. Forty-four (67%) had an extranodal MZL (EMZL), 21 (32%) a nodal MZL (NMZL), and one patient a splenic MZL. Thirty-three patients (50%) received a variable combination of adjuvant chemotherapy/immunotherapy/radiotherapy, while the remainder, including 20 of 21 with NMZL, entered an active observation period. Overall survival was excellent (98 ± 2%), although 11 patients relapsed (17%; NMZL, n = 1; EMZL, n = 10), seven after any therapy and four after complete resection only. In conclusion, outcome of NZML, in particular, seems to be excellent after (in)complete resection and observation only.

The Effect of Interim FDG-PET-guided Response-Adapted Therapy in Pediatric Patients with Hodgkin's Lymphoma (HL-14) : Protocol for a Phase II Study.

This trial enrolls patients with untreated Hodgkin's lymphoma aged<20 years at diagnosis and examines the effects of omitting radiation therapy if the FDG-positron emission tomography (PET) findings after two completed cycles of combination chemotherapy are negative. It thereby aims to determine whether patients who truly require radiation therapy can be identified by FDG-PET. If so, this modality could be used to omit radiation therapy for all other patients, decreasing the risk of serious long-term complications without affecting survival rates. The outcomes of patients for whom FDG-PET is used to assess early treatment response will also be determined.

Clinical outcomes in the first year of remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome.

OBJECTIVE: We investigated clinical outcomes in patients with remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome. METHODS: This is a retrospective multicenter study conducted in Nagasaki, Japan. We consecutively diagnosed a total of 41 patients with RS3PE syndrome between October 2003 and September 2012 and evaluated their outcomes from medical records from the first year of follow-up. RESULTS: Although an excellent initial response to corticosteroids was noted in all 41 patients, 34 (82.9%) were still receiving corticosteroids and 13 (31.7%) showed elevated C-reactive protein (CRP) at one year. Multivariate analysis demonstrated that male gender and high CRP level at entry were independent variables associated with patients' one-year CRP level being ≥0.5 mg/dL. Odds ratios were 17.05 ([95% CI 2.41-370.12], p < 0.026) and 12.99 ([95% CI 1.78-269.62], p < 0.0096), respectively. Twenty-four patients (58.5%) were still receiving prednisolone (PSL) ≥ 5 mg/day at one year. Disease-modifying anti-rheumatic drugs including methotrexate were required in three patients (10.3%). Neoplasms were found in 14 patients (34.1%) and 1 of these had died due to lung cancer at one year. CONCLUSIONS: RS3PE syndrome initially responds well to corticosteroids with remission of symptoms. However, outcomes of RS3PE syndrome appear to be worse than expected, and may be influenced by gender and initial CRP level.

The Potential and Limits of Hematopoietic Stem Cell Transplantation for the Treatment of Autosomal Dominant Hyper-IgE Syndrome.

PURPOSE: Autosomal dominant hyper-IgE syndrome (AD-HIES) is included among primary immunodeficiencies, and results from heterozygous mutations in the signal transduction and activator of transcription 3 (STAT3) gene. AD-HIES leads to impaired Th17 cell differentiation and IL-17 production, and is associated with increased susceptibility to bacteria and fungi. It was reported that several patients with AD-HIES were treated with hematopoietic stem cell transplantation (HSCT). The efficacy of HSCT in treating AD-HIES is variable. This study aims to evaluate the long-term clinical and immunological efficacy of HSCT for AD-HIES. METHODS: We have followed for more than 8 years two patients with AD-HIES who were treated with HSCT. Their ability of IL-17 production was evaluated by flow cytometry. RESULTS: Both patients indicated the normal ability of IL-17 production and their serum IgE levels decreased after HSCT. On the other hand, they suffered from pulmonary complications of AD-HIES such as pneumatoceles and bronchiectasis even after HSCT; however, the frequency of infections was decreased. CONCLUSIONS: Although the dysfunction of STAT3 in non-hematological tissues such as the lungs could not be corrected by HSCT, AD-HIES patients with risk factors for pulmonary complications may benefit from immunological correction by HSCT before severe pulmonary complications occur. Future studies should investigate risk factors for pulmonary complications in AD-HIES patients.

Influence of ADORA2A gene polymorphism on leukoencephalopathy risk in MTX-treated pediatric patients affected by hematological malignancies.

BACKGROUND: Methotrexate (MTX) can lead to neurotoxicity and asymptomatic leukoencephalopathy. However, the mechanism of MTX-related leukoencephalopathy is obscure. MTX and its metabolites inhibit 5-aminoimidazole-4-carboxamide ribonucleotide formiltransferase (ATIC) and promote adenosine release. Recently, it has been reported that adenosine and its receptor are related to certain central nervous system diseases. We investigated whether adenosine pathway gene polymorphisms and clinical factors were related to MTX-related leukoencephalopathy in pediatric patients affected by hematological malignancies. PROCEDURE: Fifty-six Japanese childhood acute lymphoblastic leukemia or lymphoma patients were investigated. Patients were evaluated by magnetic resonance imaging of the brain before maintenance therapy or stem cell transplantation. Gene polymorphisms within the adenosine pathway (ATIC, adenosine A2A receptor [ADORA2A]) and the MTX pathway (methylenetetrahydrofolate reductase [MTHFR] and ABCB1) were genotyped using TaqMan assays. Clinical data were collected by accessing the medical records. MTX-related leukoencephalopathy was evaluated by a pediatric neurologist. RESULTS: Twenty-one (37%) of 56 patients developed MTX-related leukoencephalopathy. Four of 21 patients developed clinical neurotoxicity. The minor allele CC genotype of rs2298383 (ADORA2A) was associated with MTX-related leukoencephalopathy (P = 0.010, odds ratio = 5.81, 95% confidence interval 1.50-22.50). High cumulative dose of systemic MTX was associated with MTX-related leukoencephalopathy after adjusting for sex, ADORA2A polymorphism, and prolonged high MTX concentration (P = 0.042, odds ratio = 1.18, 95% confidence interval 1.01-1.37). CONCLUSIONS: ADORA2A rs2298383 and high cumulative dose of systemic MTX administration were significantly associated with MTX-related leukoencephalopathy. Our results indicate that pharmacological intervention within the adenosine pathway may be both a treatment and preventative option for MTX-related leukoencephalopathy.

Fatal warm autoimmune hemolytic anemia in a child due to IgM-type autoantibodies.

Herein is described a case of immunoglobulin M (IgM) warm autoimmune hemolytic anemia (AIHA) in a child who consequently died within 3 days of clinical onset. A previously healthy 11-year-old boy presented with fever, anemia, jaundice, and deteriorating consciousness. On direct agglutination test against group O red blood cells, agglutination was seen even at 37°C in saline, which was abolished on dithiothreitol treatment of the serum, indicating that the responsible autoantibody was IgM and had a warm-reactive capacity. A diagnosis of IgM warm AIHA was therefore made. Hemagglutination in the visceral capillaries was considered as the direct cause of organ dysfunction. The patient died due to respiratory failure. IgM warm AIHA is a very severe condition that is difficult to reverse in an advanced state. Both prompt, definite diagnosis and intervention are therefore vital to prevent severe multi-organ dysfunction in cases of IgM warm AIHA.

Statistical analysis of relation between plasma methotrexate concentration and toxicity in high-dose methotrexate therapy of childhood nonHodgkin lymphoma.

BACKGROUND: Plasma monitoring of Methotrexate (MTX) levels is a standard approach to predict MTX-related toxicities in a high-dose (HD) MTX monotherapy for childhood acute lymphoblastic leukemia. However, it is uncertain whether plasma MTX levels can predict MTX-related toxicity in the HDMTX plus additional chemotherapy for childhood B-cell nonHodgkin lymphoma (B-NHL). PROCEDURES: To statistically analyze the relationship between MTX pharmacokinetic parameters and MTX-related toxicities, we collected data from patients with delayed MTX elimination (≥1 µM at 48 hr and/or ≥0.5 µM at 72 hr) in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) BNHL 03 study. Blood MTX levels were measured at 24, 48, and 72 hr after 3 or 5 g/m2 HD-MTX administration for 24 hr. RESULTS: Three hundred and four patients received 2-4 courses of the HDMTX plus additional chemotherapy, and delayed MTX elimination was observed in 165 courses of 127 patients. In those, nephrotoxicity was significantly correlated with plasma MTX levels for each patient (P = 0.03), and also for each course (P = 0.009), but no other toxicities were correlated. Another analysis according to HDMTX courses showed no significant correlation between the first high plasma MTX levels and subsequent MTX levels in later course. It also showed that incidence of liver and gastrointestinal toxicities was most frequent in the first HDMTX course, and then sharply decreased in later courses (P < 0.001). CONCLUSIONS: Our results suggest that plasma MTX level is not a reliable predictor for adverse events except for nephrotoxicity in multiple HDMTX therapy courses in childhood B-NHL. Pediatr Blood Cancer 2015;62:279-284. © 2014 Wiley Periodicals, Inc.

Treatment of pediatric lymphoma in Japan: Current status and plans for the future.

Results of pediatric lymphoma treatment have improved markedly over the past 30 years. In Hodgkin's lymphoma, the 5 year event-free survival (EFS) was 81.5% in a retrospective study. In the ALB-NHL03 study, the 5 year EFS according to clinical stage in patients with lymphoblastic T-cell lymphoma (T-LBL) was 70.6% for stage III and 88.9% for stage IV. In mature B-cell lymphoma, the B-NHL03 study indicated that the 4 year EFS according to treatment group was 94% for group 1, 98% for group 2, 84% for group 3, and 78% for group 4. Moreover, the 2 year EFS rate was 81% in Japanese advanced stage patients based on the international ALCL99 study. Thus, EFS >80% was achieved in any subtype of pediatric lymphoma. With regard to refractory or recurrent lymphoma, however, treatment methods for improvement of the survival rate in these patients still need to be developed. Also the difference between child, and adolescent and young adult patients still needs to be clarified, and treatment protocols developed. Although lymphoma treatment does not greatly change according to country, it does differ between other countries and Japan for some subtypes of lymphoma. In particular, the results of treatment of stage III T-LBL in Japan are worse than those in the USA and Europe. The priority in future studies will be to collect data on these differences, and the reasons for these differences.

Human parechovirus-3 infection in nine neonates and infants presenting symptoms of hemophagocytic lymphohistiocytosis.

Human parechovirus-3 (HPeV-3) has been reported to cause a sepsis-like illness in neonates and young infants. We experienced the occurrence of HPeV-3 infection in nine neonates and young infants (eight boys, one girl; aged 14-52 days, median 31 days). They were admitted to our hospital with the chief complaints of fever persisting for 3-5 days (median 4 days) and lethargy. Five infants presented with abdominal distension and six had a rash (including acral reddening), as was previously reported with this viral infection. Abdominal distension with navel protrusion and acral reddening during the course were characteristic. Laboratory data were characterized by elevated values for serum AST, LDH, FDP, D-dimer, ferritin, soluble IL-2 receptor, triglyceride, choline esterase, and urinary ß(2)-microglobulin. Two of our nine patients presented with a hemophagocytic lymphohistiocytosis (HLH)-like illness and required specific therapy. These data suggest that HPeV-3 is an important virus that can cause hypercytokinemia, which sometimes leads to HLH, and systemic inflammatory response syndrome in neonates and young infants.

HPeV3-associated acute encephalitis/encephalopathy among Japanese infants.

OBJECTIVE: The current study aimed to identify and compare the clinical characteristics of human parechovirus type 3 (HPeV3)-associated acute encephalitis/encephalopathy (HPeV3E/E) between infants with abnormal brain magnetic resonance imaging (MRI) findings (typical, or MRI-positive HPeV3E/E) and those with MRI-negative findings (MRI-negative HPeV3E/E). METHODS: This is a retrospective study on patients with HPeV3 infection, and a two-step questionnaire survey performed on 837 hospitals in Japan between 2014 and 2016. RESULTS: We identified 240 infants with HPeV3 infection, of which 34 had been clinically-diagnosed HPeV3E/E (cHPeV3E/E). However, detailed clinical data were provided by 32 of the 34 patients. Among these 32, 23 had undergone MRI and were categorized into two groups, MRI-positive (n = 17) and -negative (n = 6). There were no significant intergroup differences in clinical lab results or symptoms, except for gastrointestinal symptoms that were only present in the MRI-negative patients. The MRI-positive group showed white matter involvement on brain MRI during the acute phase, and 8 patients presented with lesions on follow-up MRI. Furthermore, 4 (50%) of the 8 patients had neurological sequelae. CONCLUSION: Clinical characteristics of cHPeV3E/E patients with and without lesions on brain MRI showed no significant differences. Therefore, considering the difficulty in distinguishing febrile infants with cHPeV3E/E from those with a sepsis-like illness, during an HPeV3 infection epidemic, it is imperative to frequently perform brain MRI in febrile infants presenting with severe disease for the early diagnosis of HPeV3E/E presenting with brain lesions.

Leucine-rich alpha-2-glycoprotein 1 and angiotensinogen as diagnostic biomarkers for Kawasaki disease.

OBJECTIVE: Kawasaki disease (KD) is a systemic vasculitis in childhood that can lead to coronary artery lesions (CALs). Although early diagnosis and treatment is important for preventing KD patients from development of CALs, diagnosis depends on the clinical features of KD. We studied the usefulness of leucine-rich alpha-2-glycoprotein 1 (LRG1) and angiotensinogen (AGT), previously reported as KD-related proteins, for KD diagnosis and estimation of intravenous immunoglobulin (IVIG) efficacy. METHODS: We undertook a prospective cohort study with patients having two or more KD symptoms in multiple centers in Japan, between July 2017 and February 2019. RESULTS: Two hundred forty-two patients were included. In multivariable analysis, one unit increase in LRG1 was associated with higher odds of KD diagnosis (Odds ratio [OR] 1.02 [95% confidence interval (CI) 1.001-1.03]). Double-positivity for AGT (≥ 26 µg/mL) and LRG1 (≥ 123.5 µg/mL) was an independent biomarker for KD diagnosis in both the total cohort and the subgroup of patients with two to four KD symptoms (OR 5.01 [95% CI 1.86-13.50] and 3.71 [95% CI 1.23-11.16], respectively). There was no association between LRG1/AGT and IVIG efficacy. CONCLUSION: Double-positivity for LRG1 and AGT is an biomarker for KD diagnosis, especially useful in diagnosing incomplete KD from non-KD. Future studies with larger cohorts should seek to determine whether LRG1 and AGT are valuable as definitive data referred at the diagnosis of KD and for estimating the risk of CALs.

Influence of CYP3A5 and ABCB1 gene polymorphisms on calcineurin inhibitor-related neurotoxicity after hematopoietic stem cell transplantation.

BACKGROUND: One severe side effect of calcineurin inhibitors (CNIs: such as cyclosporine [CsA] and tacrolimus [FK506]) is neurotoxicity. CNIs are substrates for CYP3A5 and P-glycoprotein (P-gp), encoded by ABCB1 gene. In the present study, we hypothesized that genetic variability in CYP3A5 and ABCB1 genes may be associated with CNI-related neurotoxicity. METHODS: The effects of the polymorphisms, such as CYP3A5 A6986G, ABCB1 C1236T, G2677T/A, and C3435T, associated with CNI-related neurotoxicity were evaluated in 63 patients with hematopoietic stem cell transplantation. RESULTS: Of the 63 cases, 15 cases developed CNI-related neurotoxicity. In the CsA patient group (n = 30), age (p = 0.008), hypertension (p = 0.017), renal dysfunction (p < 0.001), ABCB1 C1236T (p < 0.001), and G2677T/A (p = 0.014) were associated with neurotoxicities. The CC genotype at ABCB1 C1236T was associated with it, but not significantly so (p = 0.07), adjusted for age, hypertension, and renal dysfunction. In the FK506 patient group (n = 33), CYP3A5 A6986G (p < 0.001), and ABCB1 C1236T (p = 0.002) were associated with neurotoxicity. At least one A allele at CYP3A5 A6986G (expressor genotype) was strongly associated with it according to logistic regression analysis (p = 0.01; OR, 8.5; 95% CI, 1.4-51.4). CONCLUSION: The polymorphisms in CYP3A5 and ABCB1 genes were associated with CNI-related neurotoxicity. This outcome is probably because of CYP3A5 or P-gp functions or metabolites of CNIs.

Retrospective analysis of non-anaplastic peripheral T-cell lymphoma in pediatric patients in Japan.

BACKGROUND: Reports of non-anaplastic peripheral T-cell lymphoma (PTCL) in pediatric patients are relatively rare. PROCEDURE: We performed a retrospective analysis in patients with PTCL over an 18-year period (1991-2008). RESULTS: We could analyze clinical data in 21 patients with non-anaplastic PTCL; 10 were female and 10 male. Median age of onset was 11 years (range: 1-21 years). There were nine patients with PTCL, not otherwise specified (PTCL-NOS); ten with extranodal NK/T-cell lymphoma, nasal type; one with angioimmunoblastic T-cell lymphoma; and one with subcutaneous panniculitis-like T-cell lymphoma. Initial lesions involved cervical lymph nodes in five patients, and the skin in five patients. In five patients, hemophagocytic syndrome (HPS) was the initial clinical feature. There were 12 patients with advanced stage disease (stages III and IV). Chemotherapy and radiation was administered in 18 and 2 patients, respectively. Among the two patients who did not receive chemotherapy and radiation, one patient died while being treated for HPS but another improved spontaneously. Although 5 patients relapsed, 18 of 21 patients remained alive without disease at last follow-up. Five-year overall survival rate was 85.2%. CONCLUSIONS: Generally, the outcome results of conventional chemotherapy for high-risk PTCL are poor in adult patients. However, the excellent results in our study suggest that PTCL of childhood is quite different from that of adulthood. Although this study is first report about PTCL of Asian children, the number of patients was small in this study. Larger studies are needed to confirm these findings.

A case of fetal leukemia with intracranial hemorrhage and early-onset jaundice. Fetal leukemia with intracranial hemorrhage and jaundice.

We report a case of a neonate who was diagnosed as having congenital leukemia after presenting with an intracranial hemorrhage. The chief symptom was early-onset jaundice due to the hemorrhage. The intracranial hemorrhage and post-hemorrhage hydrocephalus advanced. In addition, the leukemia worsened leading to death at 14 days old. The possibility of leukemia, although rare, should be considered as a cause of intracranial hemorrhage in term babies.

Intracellular-to-total water ratio explains the variability of muscle strength dependence on the size of the lower leg in the elderly.

Bioelectrical impedance spectroscopy (BIS) can assess intracellular water (ICW) and total water (TW) in limbs. This study aimed to examine whether BIS can explain a part of the inter-individual variation of the muscle size-strength relationship in older adults. We analyzed the data of 79 participants aged 64-86 years. The maximal voluntary isometric torques of dorsiflexion and plantar flexion on the right side were measured. The anterior and posterior muscle thickness (MT) in the right lower leg was assessed using ultrasonography. The length of the right lower leg (L) was measured, and the ICW-to-TW ratio (ICW/TW) in the right lower leg was obtained using BIS. The MT was multiplied by L to represent an index of muscle volume (MV). Correlation and stepwise regression analyses were performed. The anterior and posterior MT × L significantly and positively correlated with the muscle torque of dorsiflexion and plantar flexion (r = 0.710 and 0.649, respectively, P < 0.001). In the stepwise regression analyses, ICW/TW was selected as a significant predictor of muscle torque independent of MT × L (P < 0.05) for both dorsiflexion and plantar flexion. Electrical parameters of BIS (membrane capacitance, characteristics frequency, and phase angle) in the lower leg also significantly correlated with muscle torques. In addition, the skeletal muscle mass index (appendicular lean mass/height2) was also associated with ICW/TW (P < 0.001). The present results suggest that ICW/TW explains the interindividual variations of the muscle size-strength relationship.

Interpretation of acid α-glucosidase activity in creatine kinase elevation: A case of Becker muscular dystrophy.

BACKGROUND: Diagnosis of Pompe disease is sometimes challenging because it exhibits clinical similarities to muscular dystrophy. CASE: We describe a case of Becker muscular dystrophy (BMD) with a remarkable reduction in activity of the acid α-glucosidase (GAA) enzyme, caused by a combination of pathogenic mutation and polymorphism variants resulting in pseudodeficiency in GAA. The three-year-old boy demonstrated asymptomatic creatine kinase elevation. Neither exon deletion nor duplication was detected on multiplex ligation-dependent probe amplification (MLPA) of DMD. GAA enzyme activity in both dried blood spots and lymphocytes was low, at 11.7% and 7.7% of normal, respectively. However, genetic analysis of GAA detected only heterozygosity for a nonsense mutation (c.118C > T, p.Arg40∗). Muscle pathology showed no glycogen deposits and no high acid phosphatase activity. Hematoxylin-eosin staining detected scattered regenerating fibers; the fibers were faint and patchy on immunochemistry staining of dystrophin. The amount of dystrophin protein was reduced to 11.8% of normal, on Western blotting analysis. Direct sequencing analysis of DMD revealed hemizygosity for a nonsense mutation (c.72G > A, p.Trp24∗). The boy was diagnosed with BMD, despite remarkable reduction in GAA activity; further, he demonstrated heterozygosity for [p.Gly576Ser; p.Glu689Lys] polymorphism variants that indicated pseudodeficiency on another allele in GAA. CONCLUSIONS: Pseudodeficiency alleles are detected in approximately 4% of the Asian population; these demonstrate low activity of acid α-glucosidase (GAA), similar to levels found in Pompe disease. Clinicians should be careful in their interpretations of pseudodeficiency alleles that complicate diagnosis in cases of elevated creatine kinase.