Knockdown of Chronophage in the nervous system mimics features of neurodevelopmental disorders caused by BCL11A/B variants.

Neurodevelopmental disorders (NDD) are a group of disorders that include intellectual disability. Although several genes have been implicated in NDD, the molecular mechanisms underlying its pathogenesis remain unclear. Therefore, it is important to develop novel models to analyze the functions of NDD-causing genes in vivo. Recently, rare pathogenic variants of the B-cell lymphoma/leukemia11A/B (BCL11A/B) gene have been identified in several patients with NDD. Drosophila carries the Chronophage (Cph) gene, which has been predicted to be a homolog of BCL11A/B based on the conservation of the amino acid sequence. In the present study, we investigated whether nervous system-specific knockdown of Cph mimics NDD phenotypes in Drosophila. Nervous system-specific knockdown of Cph induced learning and locomotor defects in larvae and epilepsy-like behaviors in adults. The number of synaptic branches was also elevated in the larval neuromuscular junction without a corresponding increase in the number of boutons. Furthermore, the expression levels of putative target genes that are Drosophila homologs of the mammalian BCL11 target genes were decreased in Cph knockdown flies. These results suggest that Cph knockdown flies are a promising model for investigating the pathology of NDD-induced BCL11A/B dysfunction.

Pleomorphic rhabdomyosarcoma in a young adult harboring a novel germline MSH2 variant.

Most cases of rhabdomyosarcoma (RMS) are sporadic and not associated with the Lynch syndrome (LS) spectrum. We report a young adult patient with RMS and a family history of colorectal cancer. Comprehensive cancer genomic profiling (CGP) of his tumor revealed a likely pathogenic variant of MSH2, NM_000251.3:c.1741delA (p.I581Lfs*9), which was also present in his blood sample. The widespread use of CGP may reveal that RMS can be a rare manifestation of LS.

TUBB3 E410K Syndrome With Childhood-Onset Nonalcoholic Steatohepatitis.

CONTEXT: Nonalcoholic fatty liver disease (NAFLD) is becoming a major issue worldwide, even in children. Multiple parallel hits hypothesis has been suggested as progress of NAFLD, but the mechanism of NAFLD is not completely understood. ß-Tubulin is essential in mitoses, neuronal migration, and axon guidance during neuronal development. Pathogenic variants in the TUBB3 gene were shown to be associated with a wide spectrum of neurological abnormalities, but not accompanied by hepatic complications, such as NAFLD. OBJECTIVE: This work aims to examine the association between TUBB3 mutation and nonalcoholic steatohepatitis (NASH). METHODS: An 11-year-old girl has been followed up as having atypical Möbius syndrome since infancy, as she was born with bilateral ptosis, paralytic strabismus, and facial weakness. At age 7 years, she was diagnosed with TUBB3 E410K syndrome by whole-exome sequencing. At age 10 years, her blood examination revealed elevated liver transaminase levels, which persisted for almost 2 years. She underwent liver biopsy, the results of which were suggestive of NASH. RESULTS: The expression of TUBB3 was absent, but that of tyrosine hydroxylase (TH) was present in the parenchymal nerve fibers of the liver. On the other hand, in comparison with an autopsy case of NASH and a normal control, these showed coexpression of TUBB3 and TH in the liver. CONCLUSION: We report the first case of TUBB3 E410K syndrome accompanied by NASH. This case suggests that the TUBB3 mutation may be associated with the pathogenesis and progression of NASH in humans.

Complex hereditary spastic paraplegia associated with episodic visual loss caused by ACO2 variants.

Most patients with homozygous or compound heterozygous pathogenic ACO2 variants present with muscular hypotonia features, namely, infantile cerebellar-retinal degeneration. Recently, two studies reported rare familial cases of ACO2 variants presenting as complex hereditary spastic paraplegia (HSP) with broad clinical spectra. Here, we report the case of a 20-year-old Japanese woman with complex HSP caused by compound heterozygous ACO2 variants, revealing a new phenotype of episodic visual loss during febrile illness.

A novel Drosophila model for neurodevelopmental disorders associated with Shwachman-Diamond syndrome.

Genetic defects in ribosome biogenesis result in a group of diseases called ribosomopathies. Patients with ribosomopathies manifest multiorgan phenotypes, including neurological impairments. A well-characterized ribosomopathy, Shwachman-Diamond syndrome (SDS), is mainly associated with loss-of-function mutations in the causal gene SBDS. Children with SDS have neurodevelopmental disorders; however, the neurological consequences of SBDS dysfunction remain poorly defined. In the present study, we investigated the phenotype of Drosophila melanogaster following knockdown of CG8549, the Drosophila ortholog of human SBDS, to provide evidence for the neurological consequences of reduction in physiological SBDS functions. The pan-neuron-specific knockdown of CG8549 was associated with locomotive disabilities, mechanically induced seizures, hyperactivity, learning impairments, and anatomical defects in presynaptic terminals. These results provide the first evidence of a direct link between a reduction in physiological SBDS function and neurological impairments.

Intrathecal nusinersen treatment after ventriculo-peritoneal shunt placement: A case report focusing on the neurofilament light chain in cerebrospinal fluid.

BACKGROUND: In July 2018, a rare and serious adverse effect (AE), namely, communicating hydrocephalus unrelated to meningitis or bleeding, was reported in relation to five patients treated with nusinersen for spinal muscular atrophy (SMA). Some patients were managed using a ventriculo-peritoneal shunt (VPS) implant and continued to receive nusinersen treatment. However, there is limited information concerning the effectiveness and safety of nusinersen treatment for patients with a VPS. CASE REPORT: A female patient exhibited general hypotonia soon after birth and was diagnosed, using genetic analysis, with spinal muscular atrophy. She required permanent invasive ventilation from 2 months of age. She developed a progressive hydrocephalus and underwent placement of a VPS in infancy. Treatment with nusinersen was initiated when she was 7 years old. The neurofilament light-chain (NfL) concentration in the cerebrospinal fluid (CSF) decreased over time with nusinersen treatment. Twelve months have passed since the start of nusinersen treatment and no AEs have been observed. CONCLUSION: Nusinersen treatment may be effective and safe, even after placement of a VPS. NfL levels in the CSF could be valuable markers of disease activity/treatment response even in advanced stages of SMA.

A 5-Year Follow-Up of Triple-Seronegative Myasthenia Gravis Successfully Treated with Tacrolimus Therapy.

Seronegative myasthenia gravis (MG) is a generalized form of MG that is diagnosed on the basis of clinical symptoms, electrophysiological testing, and pharmacological responses, in the absence of a seropositive status for anti-acetylcholine receptor (AChR) antibodies. Generalized MG that is seronegative for anti-AChR, anti-muscle-specific kinase (MuSK), and anti-low density lipoprotein receptor related protein 4 (Lrp4) antibodies is known as triple-seronegative MG. We here describe a case of triple-seronegative MG in an 8-year-old boy. His first symptom was dysphagia, at 3 years of age, and he subsequently developed ptosis, rhinolalia, and a waddling gait. A genetic analysis was conducted to exclude the possibility of congenital myasthenia syndrome due to the patient's resistance to steroid therapy. His condition was successfully managed with tacrolimus therapy over a 5-year follow-up period. Recently, several studies have reported the therapeutic utility of tacrolimus in juvenile seropositive MG; in contrast, a few reports have described tacrolimus treatment in cases of seronegative MG. Our findings suggest that tacrolimus therapy is a safe and effective option for the treatment of juvenile seronegative MG.

Luteolin attenuates interleukin-6-mediated astrogliosis in human iPSC-derived neural aggregates: A candidate preventive substance for maternal immune activation-induced abnormalities.

Maternal infection during pregnancy increases the risk of neurodevelopmental conditions such as autism spectrum disorders and schizophrenia in offspring. Several previous animal studies have indicated that maternal immune activation (MIA), rather than a specific pathogen, alters fetal brain development. Among them, prenatal exposure to interleukin-6 (IL-6) has been associated with behavioral and neuropathological abnormalities, though such findings remain to be elucidated in humans. We developed a human cell-based model of MIA by exposing human induced pluripotent stem cells (hiPSCs)-derived neural aggregates to IL-6 and investigated whether luteolin-a naturally occurring flavonoid found in edible plants-could prevent MIA-induced abnormalities. We generated neural aggregates from hiPSCs using the serum-free floating culture of embryoid body-like aggregates with quick reaggregation (SFEBq) method, following which aggregates were cultured in suspension. We then exposed the aggregates to IL-6 (100ng/ml) for 24h at day 51. Transient IL-6 exposure significantly increased the area ratio of astrocytes (GFAP-positive area ratio) and decreased the area ratio of early-born neurons (TBR1-positive or CTIP2-positive area ratio) relative to controls. In addition, western blot analysis revealed that levels of phosphorylated STAT3 were significantly elevated in IL-6-exposed neural aggregates. Luteolin treatment inhibited STAT3 phosphorylation and counteracted IL-6-mediated increases of GFAP-positive cells and reductions of TBR1-positive and CTIP2-positive cells. Our observations suggest that the flavonoid luteolin may attenuate or prevent MIA-induced neural abnormalities. As we observed increased apoptosis at high concentrations of luteolin, further studies are required to determine the optimal intake dosage and duration for pregnant women.

Serial investigation of PTPN11 mutation in nonhematopoietic tissues in a patient with juvenile myelomonocytic leukemia who was treated with unrelated cord blood transplantation.

After allogeneic stem-cell transplantation, nonhematopoietic tissues contain donor-derived cells; however, whether cells from malignant hematological disease can also be found in nonhematopoietic tissues is unclear. This report describes a juvenile myelomonocytic leukemia (JMML) case with a typical PTPN11 mutation (p.E76K) at different allele frequencies in the bone marrow mononuclear cells, buccal smear cells, and fingernails at diagnosis, which was suggestive of PTPN11 somatic mosaicism; however, the PTPN11 mutation in the buccal smear cells and fingernails was lost after unrelated cord blood transplantation. These results suggest that JMML-derived cells may migrate into and reside in nonhematopoietic tissues and furthermore that these cells can be eradicated by cord blood transplantation.

Effects of chemotherapy on the brain in childhood: diffusion tensor imaging of subtle white matter damage.

INTRODUCTION: With reducing mortality in children with hematological malignancies, the survivors' quality of life regarding development of chronic neurological disturbances is important. We aimed to determine whether chemotherapy affects white matter (WM). METHODS: Using brain diffusion tensor imaging, we evaluated 17 patients (15 with acute lymphoblastic leukemia, 2 with non-Hodgkin's lymphoma; 9 male, 8 female; age, 1.6-13 years) before and after chemotherapy. We measured the quantitative values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) at the regions of interest (ROIs) such as periventricular WM, corona radiata, posterior limb of the internal capsule, and corpus callosum. We assessed sensorimotor and callosal tracts by tractography. RESULTS: Reduction in FA and increase in ADC were significant at the ROIs of the left and right anterior periventricular WM and corona radiata and at the tract passing through the genu. A significant reduction in FA with a nonsignificant increase in ADC was seen at the ROI of the genu and at the tracts passing through the body and isthmus. CONCLUSION: Chemotherapy in children with hematological malignancies predominantly affects the frontal WM. This finding might indicate a negative effect of chemotherapy on neurological development in children with hematological malignancies.

Effects of fukutin deficiency in the developing mouse brain.

The major pathological change in Fukuyama-type congenital muscular dystrophy brain is polymicrogyria. Pathological studies of Fukuyama-type congenital muscular dystrophy brain indicated that protrusion of neurons into the subarachnoid space through breaches in the glia limitans-basal lamina complex is a cardinal pathogenic process in this condition. It remains undetermined, however, whether the defect causing this abnormal migration resides in the migrating neurons or in the glia limitans-basal lamina complex. To elucidate the pathogenesis of brain abnormalities in Fukuyama-type congenital muscular dystrophy, we analyzed histologically and immunohistochemically the developing forebrain in fukutin-deficient chimeric mice and compared it with that in controls (n=4 in each group). In chimeric embryos, ectopia became apparent as early as embryonic day 14, and laminar organization became progressively distorted. The basal lamina of the cortical surface in chimeras showed defects at E14, coinciding with the earliest time point at which ectopia were detected. Immunohistochemical analysis of glycosylated alpha-dystroglycan showed progressive defects coincidental with the disruption of the basal lamina. Neuronal migration was not affected in chimeras, as determined by detection of bromodeoxyuridine-labeled neurons. Extension of radial glial fibers was intact in chimeras. Taken together, disruption of the basal lamina, caused by the loss of interaction between hypoglycosylated alpha-dystroglycan and its ligands, plays a key role in the pathogenesis of cortical dysplasia in Fukuyama-type congenital muscular dystrophy.

Granulocytic sarcoma presenting with severe adenopathy (cervical lymph nodes, tonsils, and adenoids) in a child with juvenile myelomonocytic leukemia and successful treatment with allogeneic bone marrow transplantation.

The occurrence of adenopathy in patients with myelodysplastic syndrome-associated extramedullary myeloid cell tumors has rarely been reported. We describe a 7-year-old girl with juvenile myelomonocytic leukemia who showed the novel chromosomal abnormality t(9;12)(p22;q24.1) and who developed severe adenopathy of the cervical lymph nodes, tonsils, and adenoids that was manifested as granulocytic sarcoma. Following chemotherapy, the patient underwent a conditioning regimen of busulfan, cyclophosphamide, and total body irradiation followed by successful allogeneic bone marrow transplantation from her single HLA locus-mismatched mother at 6 months after her diagnosis. The patient continues to be well and in remission 3 years after stem cell transplantation.

Early blastic transformation following complete cytogenetic response in a pediatric chronic myeloid leukemia patient treated with imatinib mesylate.

This article reports early blastic transformation of chronic myeloid leukemia (CML) in a child following a complete cytogenetic response induced by imatinib mesylate. A 14-year-old Japanese boy was diagnosed with t(9;22) cryptic CML in the chronic phase and treated with imatinib. His response to treatment was slow, but a major cytogenetic response was obtained at 142 days of therapy. However, he developed lymphoid blastic transformation at 9 months. He attained remission with acute lymphoblastic leukemia-type chemotherapy and then successfully received a non-T-cell-depleted allogeneic stem cell transplantation (allo-SCT) with his mother's two loci-mismatched donor cells. A sudden blastic transformation may occur even with a complete cytogenetic response induced by imatinib. CML patients who respond slowly to imatinib may still be candidates for allo-SCT, even when a major cytogenetic response is obtained.