Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by multiple hamartias and hamartomas involving throughout the body. To date, many TSC1 and TSC2 mutations have been reported all over the world, however, few TSC mutation studies have been performed in the Japanese population, and genetic characteristics of Japanese TSC patients are not yet clear. In this study, we analyzed TSC1 and TSC2 in 57 Japanese patients with TSC (8 familial and 49 sporadic; 46 definite and 11 suspect TSC) and identified 31 mutations including 11 TSC1 mutations (two familial and nine sporadic; all definite TSC) and 20 TSC2 mutations (2 familial and 18 sporadic; 19 definite and 1 suspect TSC). We also reviewed all Japanese TSC mutations previously reported. Our study demonstrates significantly higher incidence (P=0.007) of TSC1 mutations among sporadic TSC patients in the Japanese population compared with US and European studies. No differences emerged in mutation distributions and types in precedent studies, excepting low frequency of the TSC2 nonsense mutation. Comparing clinical manifestations, developmental delay and/or mental retardation were milder in TSC1 patients than TSC2 patients for its frequency (P=0.032) and severity (P=0.015); however, no other symptoms were clearly different.

Objective: Patients with severe motor and intellectual disabilities (SMID) often develop complications, including paralysis of the extremities due to abnormal muscular tonicity. Furthermore, the incidence of sudden death, which may be caused by pulmonary thromboembolism (PTE), is approximately 4.2%. Deep vein thrombosis (DVT) is attracting attention as an embolic source. In this study, DVT was confirmed in SMID patients by lower extremity venous ultrasound. The oral anticoagulant, warfarin, and novel oral anticoagulant, edoxaban tosilate hydrate, were administered, and their efficacies and safeties were evaluated.Materials and Methods: DVT patients were randomly allocated to warfarin and edoxaban groups. The frequency of hemorrhagic events and incidence of adverse events were investigated to evaluate efficacy and safety.Results: DVT was detected in 14 (8.4%) out of 167 patients. Four (0.067/person-month) hemorrhagic events occurred in the warfarin group from subcutaneous hemorrhage due to bruises caused by postural changes. Three (0.042/person-month) events occurred in the edoxaban group due to nasal hemorrhage caused by tracheal aspiration. There was no significant difference (p=0.5383) between groups.Conclusion: No significant differences were observed in hemorrhagic events between SMID patients with DVT treated with warfarin and edoxaban.

Subependymal giant cell astrocytoma (SEGA) is a unique brain tumor arising in tuberous sclerosis complex (TSC), an autosomal dominant inherited phacomatosis. There are several case reports of solitary SEGA without any other manifestations of TSC. Usually these cases are thought to be forme fruste of TSC due to somatic mosaicism. However, no previous reports have used molecular methodology to fully investigate mutations in TSC genes or the possibility of somatic mosaicism. Here, we report a 20-year-old woman with a brain tumor. Pathological diagnosis was consistent with SEGA, but comprehensive clinical screening found no other lesions indicative of TSC. Molecular analysis of the tumor revealed loss of heterozygosity and allelic mutation (5228G>A, R1743Q) of TSC2. To detect the small fraction of mosaic mutation in somatic cells, we developed a highly sensitive new method: triple-nested polymerase chain reaction-restriction fragment length polymorphism. The identical TSC2 missense mutation was not detected in any other tissues from the same patient, including peripheral blood, buccal mucosa, urinary sediment, nail, and hair. According to these results, this patient should be considered as having SEGA that developed from two somatic hit mutations in TSC2, rather than being a TSC2 patient with a very small fraction of somatic mosaicism.

Sudden death in patients with severe motor and intellectual disabilities (SMID) is sometimes caused in part by pulmonary thromboembolism (PTE), and deep venous thrombosis (DVT) has drawn attention as a possible embolic source. Warfarin, which is a conventional therapeutic agent, is not easy to control appropriately, and daily management can be especially difficult in SMID patients. On the other hand, edoxaban tosilate hydrate, which has been newly approved for insurance coverage for the treatment of DVT, is not listed in the Guidelines for the Diagnosis, Treatment and Prevention of Pulmonary Thromboembolism and Deep Vein Thrombosis (DVT-PTE guidelines). The aim of this study is to evaluate the efficacy and safety of anticoagulation therapy (warfarin vs. edoxaban) in DVT treatment in SMID patients by means of an open-label, randomized controlled trial. The primary endpoint is the incidence of hemorrhagic events during 12 months of follow up.