Hideki Uchikawa

Frameshift mutation in the PTCH2 gene can cause nevoid basal cell carcinoma syndrome

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis. The gene responsible for NBCCS is PTCH1, encoding a receptor for the secreted protein, sonic hedgehog. Recently, a Chinese family with NBCCS carrying a missense mutation in PTCH2, a close homolog of PTCH1, was reported. However, the pathological significance of missense mutations should be discussed cautiously. Here, we report a 13-year-old girl diagnosed with NBCCS based on multiple keratocystic odontogenic tumors and rib anomalies carrying a frameshift mutation in the PTCH2 gene (c.1172_1173delCT). Considering the deleterious nature of the frameshift mutation, our study further confirmed a causative role for the PTCH2 mutation in NBCCS. The absence of typical phenotypes in this case such as palmar/plantar pits, macrocephaly, falx calcification, hypertelorism and coarse face, together with previously reported cases, suggested that individuals with NBCCS carrying a PTCH2 mutation may have a milder phenotype than those with a PTCH1 mutation.

U7 snRNA-mediated correction of aberrant splicing caused by activation of cryptic splice sites

AbstractA considerable fraction of mutations associated with hereditary disorders and cancers affect splicing. Some of them cause exon skipping or the inclusion of an additional exon, whereas others lead to the inclusion of intronic sequences or deletion of exonic sequences through the activation of cryptic splice sites. We focused on the latter cases and have designed a series of vectors that express modified U7 small nuclear RNAs (snRNAs) containing a sequence antisense to the cryptic splice site. Three cases of such mutation were investigated in this study. In two of them, which occurred in the PTCH1 and BRCA1 genes, canonical splice donor sites had been partially impaired by mutations that activated nearby intronic cryptic splice donor sites. Another mutation found in exonic region in CYP11A created a novel splice donor site. Transient expression of the engineered U7 snRNAs in HeLa cells restored correct splicing in a sequence-specific and dose-dependent manner in the former two cases. In contrast, the third case, in which the cryptic splice donor site in the exonic sequence was activated, the expression of modified U7 snRNA resulted in exon skipping. The correction of aberrant splicing by suppressing intronic cryptic splice sites with modified U7 is expected be a promising alternative to gene replacement therapy.

Detection of 14-3-3 protein in the cerebrospinal fluid in mitochondrial encephalopathy with lactic acidosis and stroke-like episodes

We describe a 13-year-old boy with mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) who experienced a stroke-like episode resulting in severe mental regression and quadriplegia. We tested 14-3-3 protein in the cerebrospinal fluid (CSF) of the patient four times around a stroke-like episode in a magnetic resonance imaging (MRI) study. Detection of the protein in the CSF was well correlated with the clinical course and range of damage of the brain lesion on MRI. Interestingly, 14-3-3 CSF protein was detected at the beginning of mitochondrial encephalopathy without new MRI abnormalities, suggesting that it is a sensitive brain marker. We conclude that 14-3-3 CSF protein is a useful biological marker of brain disruption in MELAS as well as other neurological disorders.

14-3-3 Protein Detection in the Cerebrospinal Fluid of Patients With Influenza-Associated Encephalopathy

Influenza-associated encephalopathy is characterized by high fever, convulsions, and loss of consciousness associated with influenza infection in children, but its pathophysiology remains to be clarified. We examined 14-3-3 proteins, which

Reversible cerebral vasoconstriction syndrome associated with brain parenchymal hemorrhage

We described a 7-year-old girl with reversible cerebral vasoconstriction syndrome associated with brain parenchymal hemorrhage. She initially presented with high fever and pancytopenia, leading to a diagnosis of most severe type aplastic anemia. We treated her with cyclosporine, methylprednisolone and anti-thymocyte globulin. Thereafter she recurrently complained of a very severe headache called as thunderclap, and finally exhibited loss of consciousness. Brain imaging revealed massive parenchymal hemorrhage between the left occipital and parietal lobes on computed tomography, and diffuse cerebral vasoconstriction on magnetic resonance angiography. The cerebral vasoconstriction resolved within two months, and thus we diagnosed her as having reversible cerebral vasoconstriction syndrome associated with brain parenchymal hemorrhage. This syndrome has been frequently reported in adult females, but rarely in children. However, even in children, a so called thunderclap headache may become a clue for the diagnosis of reversible cerebral vasoconstriction syndrome, especially in cases taking immunosuppressive agents. Immediate magnetic resonance angiography is essential to diagnose this syndrome, and a prompt application of calcium channel inhibitors should be considered to resolve constriction of the vessels and to prevent subsequent brain damage.

Multiple cavitations in posterior reversible leukoencephalopathy syndrome associated with hemolytic-uremic syndrome

We describe a 4-year-old boy with posterior reversible leukoencephalopathy syndrome associated with hemolytic-uremic syndrome. He exhibited bloody stool by Escherichia coli O157: H7 infection with acute renal failure. He subsequently presented high blood pressure, followed by visual disturbance and loss of consciousness. Brain MRI revealed bilateral occipital high intensities by T2-weighted images and high value by apparent diffusion coefficient map, thus we made a diagnosis of posterior reversible leukoencephaly syndrome associated with hemolytic-uremic syndrome. In spite of immediate blood pressure control, occipital lesions developed day by day, resulting in multiple subcortical cavitations. Although posterior reversible leukoencephalopathy syndrome is originally characterized by reversible vasogenic edema, this case rarely resulted in irreversible changes with cystic formation. We concluded that precipitating factors, i.e., clotting abnormalities, Shiga toxin, vasospasms and endothelial dysfunction might have synergistically induced irreversible brain infarcts, and caused unusual cavitations.

Hedgehog signaling is synergistically enhanced by nutritional deprivation and ligand stimulation in human fibroblasts of Gorlin syndrome.

Hedgehog signaling is a pivotal developmental pathway that comprises hedgehog, PTCH1, SMO, and GLI proteins. Mutations in PTCH1 are responsible for Gorlin syndrome, which is characterized by developmental defects and tumorigenicity. Although the hedgehog pathway has been investigated extensively in Drosophila and mice, its functional roles have not yet been determined in human cells. In order to elucidate the mechanism by which transduction of the hedgehog signal is regulated in human tissues, we employed human fibroblasts derived from three Gorlin syndrome patients and normal controls. We investigated GLI1 transcription, downstream of hedgehog signaling, to assess native signal transduction, and then treated fibroblasts with a recombinant human hedgehog protein with or without serum deprivation. We also examined the transcriptional levels of hedgehog-related genes under these conditions. The expression of GLI1 mRNA was significantly higher in Gorlin syndrome-derived fibroblasts than in control cells. Hedgehog stimulation and nutritional deprivation synergistically enhanced GLI1 transcription levels, and this was blocked more efficiently by vismodegib, a SMO inhibitor, than by the natural compound, cyclopamine. Messenger RNA profiling revealed the increased expression of Wnt signaling and morphogenetic molecules in these fibroblasts. These results indicated that the hedgehog stimulation and nutritional deprivation synergistically activated the hedgehog signaling pathway in Gorlin syndrome fibroblasts, and this was associated with increments in the transcription levels of hedgehog-related genes such as those involved in Wnt signaling. These fibroblasts may become a significant tool for predicting the efficacies of hedgehog molecular-targeted therapies such as vismodegib.

14-3-3 Proteins, particularly of the epsilon isoform, are detectable in cerebrospinal fluids of cerebellar diseases in children

BACKGROUND Detection of 14-3-3 proteins in cerebrospinal fluid (CSF) is a powerful tool for elucidating the mechanisms of neurological disorders. There have been useful studies on 14-3-3 CSF protein detection in Creutzfeldt-Jakob disease and other neurological disorders, but none on cerebellar diseases. OBJECTIVE To elucidate whether 14-3-3 CSF proteins are a sensitive biomarker of cerebellar disruption in children. MATERIALS AND METHODS We examined 14-3-3 CSF proteins by immunoblotting in seven patients with cerebellar disorders: two with acute cerebellitis, two with acute cerebellar ataxia, and three with cerebellar atrophy. We also investigated 14-3-3 CSF proteins in four cases of febrile seizure and three of influenza-related encephalopathy. Isoforms of 14-3-3 proteins were also identified using isoform-specific antibodies. RESULTS 14-3-3 proteins were detected in CSF of six patients with cerebellar disorders, the exception being one with acute cerebellar ataxia caused by viral infection. Interestingly, only the 14-3-3 ε isoform was detected in two tested patients with cerebellar involvement. Moreover, longitudinal analysis of 14-3-3 CSF proteins in one patient with infantile neuroaxonal dystrophy showed that the 14-3-3 band density proportionally decreased when the cerebellar atrophy gradually progressed. Another CSF derived from a case of febrile seizure showed no 14-3-3 proteins, whereas all those derived from influenza-related encephalopathy demonstrated 14-3-3 CSF proteins with six isoforms. CONCLUSIONS This is the first report on 14-3-3 CSF proteins as a significant biomarker of cerebellar disruption, as well as other brain diseases. Since 14-3-3 ε is localized in the molecular layer of cerebellum, the unique detection of 14-3-3 ε may indicate cerebellar involvement in the brain.

Brain morphology in children with nevoid basal cell carcinoma syndrome

Brain morphology is tightly regulated by diverse signaling pathways. Hedgehog signaling is a candidate pathway considered responsible for regulating brain morphology. Nevoid basal cell carcinoma syndrome (NBCCS), caused by a PTCH1 mutation in the hedgehog signaling pathway, occasionally exhibits macrocephaly and medulloblastoma. Although cerebellar enlargement occurs in ptch1 heterozygous‐deficient mice, its impact on human brain development remains unknown. We investigated the brain morphological characteristics of children with NBCCS. We evaluated brain T1‐weighted images from nine children with NBCCS and 15 age‐matched normal control (NC) children (mean [standard deviation], 12.2 [2.8] vs. 11.6 [2.3] years old). The diameters of the cerebrum, corpus callosum, and brain stem and the cerebellar volume were compared using two‐tailed t‐tests with Welchs correction. The transverse diameters (150.4 [9.9] vs. 136.0 [5.5] mm, P = 0.002) and longitudinal diameters (165.4 [8.0] vs. 151.3 [8.7] mm, P = 0.0007) of the cerebrum, cross‐sectional area of the cerebellar vermis (18.7 [2.6] vs. 11.8 [1.7] cm2, P = 0.0001), and total volume of the cerebellar hemispheres (185.1 [13.0] vs. 131.9 [10.4] cm3, P = 0.0001) were significantly larger in the children with NBCCS than in NC children. Thinning of the corpus callosum and ventricular enlargement were also confirmed in children with NBCCS. We demonstrate that, on examination of the brain morphology, an increase in the size of the cerebrum, cerebellum, and cerebral ventricles is revealed in children with NBCCS compared to NC children. This suggests that constitutively active hedgehog signaling affects human brain morphology and the PI3K/AKT and RAS/MAPK pathways.

Phrenic nerve palsy associated with birth trauma – Case reports and a literature review

Phrenic nerve palsy is a peripheral nerve disorder caused by excessive cervical extension due to birth trauma or cardiac surgery. We describe two new patients with phrenic nerve palsy associated with birth trauma. Both patients exhibited profound dyspnea and general hypotonia immediately after birth. A chest roentgenogram and fluoroscopy revealed elevation of the diaphragm, leading to a diagnosis of phrenic nerve palsy associated with birth trauma. Since they had intermittently exhibited dyspnea and recurrent infection, we performed video-assisted thoracoscopic surgery (VATS) plication in both cases, at an early and a late stage, respectively. Both patients subsequently exhibited a dramatic improvement in dyspnea and recurrent respiratory infection. Interestingly, the late stage operated infant exhibited spontaneous recovery at 7 months with cessation of mechanical ventilation once. However, this recovery was transient and subsequently led to an increased ventilation volume demand, finally resulting in surgical treatment at 15 months. Histological examination of the diaphragm at this time showed grouped muscle atrophy caused by phrenic nerve degeneration. To our knowledge, this is the first pathologically proven report of grouped muscle atrophy of the diaphragm due to phrenic nerve degeneration, suggesting that partial impairment of phrenic nerves resulted in respiratory dysfunction with incomplete recovery. We conclude that recently developed VATS plication is a safe and effective treatment for infants with phrenic nerve palsy, and should be considered as a surgical treatment at an early period.