Multiple pulmonary artery aneurysms in tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is a rare genetic disorder characterised by multiple hamartomas, caused by inactivating mutations of the TSC1/TSC2 tumour suppressor genes. Classical pulmonary involvement in tuberous sclerosis complex (TSC) consists of lymphangioleiomyomatosis and/or multiple micronodular pneumocyte hyperplasia (MMPH). Association of TSC with pulmonary artery aneurysm (PAA) has been only exceptionally described. We report here the first case of TSC with multiple PAA in combination with MMPH, cardiac rhabdomyomas and bone, skin and brain involvement.

Tuberous sclerosis complex with oral manifestations: A case report and literature review

Introduction: Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome produced by a number of genetic mutations. The disease is characterized by the development of benign tumors affecting different body systems. The most common oral manifestations of TSC are fibromas, gingival hyperplasia and enamel hypoplasia. Clinical Case: A 35-year-old woman diagnosed with TSC presented with a reactive fibroma of considerable size and rapid growth in the region of the right lower third molar. Discussion: In the present case the association of TSC with dental malpositioning gave rise to a rapidly evolving reactive fibroma of considerable diameter. Few similar cases can be found in the literature. Patients with TSC present mutations of the TSC1 and TSC2 genes, which intervene in cell cycle regulation and are important for avoiding neoplastic processes. No studies have been found associating TSC with an increased risk of oral cancer, though it has been shown that the over-expression of TSC2 could exert an antitumor effect. Careful oral and dental hygiene, together with regular visits to the dentist, are needed for the prevention and early detection of any type of oral lesion. The renal, pulmonary and cardiac alterations often seen in TSC must be taken into account for the correct management of these patients.

CHARACTERIZING AND TREATING THE NEUROPATHOLOGY OF TUBEROUS SCLEROSIS COMPLEX IN THE MOUSE

Tuberous sclerosis complex (TSC) is a multisystem, autosomal dominant disorder affecting approximately 1 in 6000 births. Developmental brain abnormalities cause substantial morbidity and mortality and often lead to neurological disease including epilepsy, cognitive disabilities, and autism. TSC is caused by inactivating mutations in either TSC1 or TSC2, whose protein products are known inhibitors of mTORC1, an important kinase regulating translation and cell growth. Nonetheless, neither the pathophysiology of the neurological manifestations of TSC nor the extent of mTORC1 involvement in the development of these lesions is known. Murine models would greatly advance the study of this debilitating disorder. This thesis will describe the generation and characterization of a novel brain-specific mouse model of TSC, Tsc2flox/ko;hGFAP-Cre. In this model, the Tsc2 gene has been removed from most neurons and glia of the cortex and hippocampus by targeted Cre-mediated deletion in radial glial neuroprogenitor cells. The Tsc2flox/ko;hGFAP-Cre mice fail to thrive beginning postnatal day 8 and die from seizures around 23 days. Further characterization of these mice demonstrated megalencephaly, enlarged neurons, abnormal neuronal migration, altered progenitor pools, hypomyelination, and an astrogliosis. The similarity of these defects to those of TSC patients establishes this mouse as an excellent model for the study of the neuropathology of TSC and testing novel therapies. We further describe the use of this mouse model to assess the therapeutic potential of the macrolide rapamycin, an inhibitor of mTORC1. We demonstrate that rapamycin administered from postnatal day 10 can extend the life of the mutant animals 5 fold. Since TSC is a neurodevelopmental disorder, we also assessed in utero and/or immediate postnatal treatment of the animals with rapamycin. Amazingly, combined in utero and postnatal rapamycin effected a histologic rescue that was almost indistinguishable from control animals, indicating that dysregulation of mTORC1 plays a large role in TSC neuropathology. In spite of the almost complete histologic rescue, behavioral studies demonstrated that combined treatment resulted in poorer learning and memory than postnatal treatment alone. Postnatally-treated animals behaved similarly to treated controls, suggesting that immediate human treatment in the newborn period might provide the most opportune developmental timepoint for rapamycin administration.

Thoracic aortic disease in tuberous sclerosis complex: molecular pathogenesis and potential therapies in Tsc2+/- mice.

Tuberous sclerosis complex (TSC) is a genetic disorder with pleiotropic manifestations caused by heterozygous mutations in either TSC1 or TSC2. One of the less investigated complications of TSC is the formation of aneurysms of the descending aorta, which are characterized on pathologic examination by smooth muscle cell (SMC) proliferation in the aortic media. SMCs were explanted from Tsc2(+/-) mice to investigate the pathogenesis of aortic aneurysms caused by TSC2 mutations. Tsc2(+/-) SMCs demonstrated increased phosphorylation of mammalian target of rapamycin (mTOR), S6 and p70S6K and increased proliferation rates compared with wild-type (WT) SMCs. Tsc2(+/-) SMCs also had reduced expression of SMC contractile proteins compared with WT SMCs. An inhibitor of mTOR signaling, rapamycin, decreased SMC proliferation and increased contractile protein expression in the Tsc2(+/-) SMCs to levels similar to WT SMCs. Exposure to alpha-elastin fragments also decreased proliferation of Tsc2(+/-) SMCs and increased levels of p27(kip1), but failed to increase expression of contractile proteins. In response to artery injury using a carotid artery ligation model, Tsc2(+/-) mice significantly increased neointima formation compared with the control mice, and the neointima formation was inhibited by treatment with rapamycin. These results demonstrate that Tsc2 haploinsufficiency in SMCs increases proliferation and decreases contractile protein expression and suggest that the increased proliferative potential of the mutant cells may be suppressed in vivo by interaction with elastin. These findings provide insights into the molecular pathogenesis of aortic disease in TSC patients and identify a potential therapeutic target for treatment of this complication of the disease.

Inactivation of the cyclin-dependent kinase inhibitor p27 upon loss of the tuberous sclerosis complex gene-2

Tuberous sclerosis is an autosomal dominant disorder characterized by the development of aberrant growths in many tissues and organs. Linkage analysis revealed two disease-determining genes on chromosome 9 and chromosome 16. The tuberous sclerosis complex gene-2 (TSC2) on chromosome 16 encodes the tumor suppressor protein tuberin. We have shown earlier that loss of TSC2 is sufficient to induce quiescent cells to enter the cell cycle. Here we show that TSC2-negative fibroblasts exhibit a shortened G1 phase. Although the expression of cyclin E, cyclin A, p21, or Cdc25A is unaffected, TSC2-negative cells express much lower amounts of the cyclin-dependent kinase (CDK) inhibitor p27 because of decreased protein stability. In TSC2 mutant cells the amount of p27 bound to CDK2 is diminished, accompanied with elevated kinase activity. Ectopic expression studies revealed that the aforementioned effects can be reverted by transfecting TSC2 in TSC2-negative cells. High ectopic levels of p27 have cell cycle inhibitory effects in TSC2-positive cells but not in TSC2-negative counterparts, although the latter still depend on CDK2 activity. Loss of TSC2 induces soft agar growth of fibroblasts, a process that cannot be inhibited by high levels of p27. Both phenotypes of TSC2-negative cells, their resistance to the activity of ectopic p27, and the instability of endogenous p27, could be explained by our observation that the nucleoprotein p27 is mislocated into the cytoplasm upon loss of TSC2. These findings provide insights into the molecular mechanism of how loss of TSC2 induces cell cycle entry and allow a better understanding of its tumor suppressor function.

Formulation and characterization of a 0.1% rapamycin cream for the treatment of Tuberous Sclerosis Complex-related angiofibromas

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Analysis of the Dynamics and Origin of Epileptic Activity in Patients with Tuberous Sclerosis Evaluated for Surgery of Epilepsy

Objective: The epilepsies associated with the tuberous sclerosis complex (TSC) are very often refractory to medical therapy. Surgery for epilepsy is an effective alternative when the critical link between the localization of seizure onset in the scalp and a particular cortical tuber can be established. In this study we perform analysis of ictal and interictal EEG to improve such link. Methods: The ictal and interictal recordings of four patients with TSC undergoing surgery for epilepsy were submitted to independent component analysis (ICA), followed by source analysis, using the sLORETA algorithm. The localizations obtained for the ictal EEG and for the average interictal spikes were compared. Results: The ICA of ictal EEG produced consistent results in different events, and there was good agreement with the tubers that were successfully removed in three of the four patients (one patient refused surgery). In some patients there was a large discrepancy between the localization of ictal and interictal sources. The interictal activity produced more widespread source localizations. Conclusions: The use of ICA of ictal EEG followed by the use of source analysis methods in four cases of epilepsy and TSC was able to localize the epileptic generators very near the lesions successfully removed in surgery for epilepsy. Significance: The ICA of ictal EEG events may be a useful add-on to the tools used to establish the connection between epileptic scalp activity and the cortical tubers originating it, in patients with TSC considered for surgery of epilepsy.

Syndrome of birt-hogg-dubé, a histopathological pitfall with similarities to tuberous sclerosis: a report of three cases.

: Birt-Hogg-Dubé Syndrome (BHD) is a rare condition, transmitted as an autosomal-dominant trait. The etiology is due to a mutation in the BHD gene, which encodes folliculin (FLCN), located on chromosome 17p. The skin changes observed are benign skin tumors consisting of hamartomas of the hair follicle with dermal changes. Patients with BHD have an increased risk of spontaneous pneumothorax due to rupture of lung cysts and an increased risk of kidney tumors. We report 3 new cases of BHD and discuss their clinical features, histopathological findings, and molecular diagnostics. We highlight the importance of genetic analysis to confirm the diagnosis because of the clinical pitfalls involved in establishing a diagnosis. Finally, we discuss the histopathological features in BHD and tuberous sclerosis complex and focus on their overlapping criterias. A correct diagnosis is essential as it can be life saving for patients.

Prevalence of Premature Ovarian Failure in Women with Tuberous Sclerosis

Tuberous Sclerosis Complex (TSC) is an autosomal dominant tumor suppressor disorder characterized by hamartomas, or benign growths, in various organ systems. Inactivating mutations in either the TSC1 or the TSC2 gene cause most cases of TSC. Recently, the use of ovarian specific conditional knock-out mouse models has demonstrated a crucial role of the TSC genes in ovarian function. Mice with complete deletion of Tsc1 or Tsc2 showed accelerated ovarian follicle activation and subsequent premature follicular depletion, consistent with the human condition premature ovarian failure (POF). POF is defined in women as the cessation of menses before the age of 40 and elevated levels of follicle stimulating hormone (FSH). The prevalence of POF is estimated to be 1%, affecting a substantial number of women in the general population. Nonetheless, the etiology of most cases of POF remains unknown. Based on the mouse model results, we hypothesized that the human TSC1 and TSC2 genes are likely to be crucial for ovarian development and function. Moreover, since women with TSC already have one inactivated TSC gene, we further hypothesized that they may show a higher prevalence of POF. To test this hypothesis, we surveyed 1000 women with TSC belonging to the Tuberous Sclerosis Alliance, a national support organization. 182 questionnaires were analyzed for information on menstrual and reproductive function, as well as TSC. This self-reported data revealed 8 women (4.4%) with possible POF, as determined by menstrual history report and additional supportive data. This prevalence is much higher than 1% in the general population. Data from all women suggested other reproductive pathology associated with TSC such as a high rate of miscarriage (41.2%) and menstrual irregularity of any kind (31.2%). These results establish a previously unappreciated effect of TSC on women’s reproductive health. Moreover, these data suggest that perturbations in the cellular pathways regulated by the TSC genes may play an important role in reproductive function.

Toward targeted treatments in tuberous sclerosis

Introduction. Tuberous Sclerosis Complex (TSC) is an autosomal-dominant disease caused by the loss of function of the heterodimeric complex hamartin/tuberin due to TSC1/TSC2 gene mutation. The consequent abnormal activation of mammalian target of rapamycin (mTOR), a serine threonine kinase regulating cellular growth, metabolism and proliferation, is responsible for the structural and functional abnormalities observed in TSC. mTOR inhibitors are a class of drugs specifically targeting the mTOR pathway with promising benefits as a specific targeted treatment of the disease. Areas covered. We have reviewed the literature focusing on the role of mTOR inhibitors in treating TSC-related conditions. They are currently approved for subependymal giant cell astrocytomas, renal angiomyolipomas and more recently for lymphangioleiomyomatosis, but a promising role has been shown also in the other clinical manifestation characteristics of TSC, such as cardiac rhabdomyomas, facial angiofibromas and epilepsy. Expert opinion. mTOR inhibition is considered a disease-modifying therapy and the best approach to prevent the progress of the natural history of the disease. For the first time we have the possibility not only to use a biologically targeted treatment, but also to address different manifestations at the same time, thus significantly improving the therapeutic outlook in this complex disease.

Bilateral giant renal angiomyolipoma associated with hepatic lipoma in a patient with tuberous sclerosis

OBJECTIVE: To report a case of bilateral giant renal angiomyolipoma associated with tuberous sclerosis, with successful treatment, and to review the literature concerning angiomyolipoma treatment. CASE REPORT: Patient with tuberous sclerosis and angiomyolipoma diagnosed by ultrasonography during her pregnancy. At that time, the angiomyolipoma on the right side was 9 cm in diameter. Conservative management was selected during her pregnancy. The patient returned 7 years later, with a 24.7 x 19.2 x 10.7 cm tumor on the right side and another of 13 x 11.5 x 6.5 cm on the left side, in addition to multiple small angiomyolipomas. A nephron-sparing surgery with tumoral enucleation was performed on the right side, and after 3 months, the tumor on the left side was removed. Renal function in the post-operative period was preserved, and contrast medium progression was uniform and adequate in both kidneys. CONCLUSION: We conclude that an angiomyolipoma larger than 4 cm should be removed surgically, since they have a greater growth rate and pose a risk of hemorrhage. Resection of smaller tumors is safe and has decreased morbidity. Tumoral enucleation is an effective treatment method that preserves kidney function.

Tuberous sclerosis: literature review and case report

Tuberous sclerosis (TS) or Bourneville"s disease is a rare, multisystemic genetic disorder. It involves alterations to ectodermal and mesodermal cell differentiation and proliferation, causing benign hamartomatous tumors, neurofibromas and angiofibromas in the brain and other vital organs including the kidney, heart, eyes, lungs, skin and mucosa. It also affects the central nervous system and produces neurological dysfunctions such as seizures, mental retardation and behavior disorders. Tuberous (rootshaped) growths develop in the brain, and calcify over time, becoming hard and sclerotic, hence the name given to the disease. Although inheritance is autosomal dominant, 60-70% of cases occur through spontaneous mutations. The disease is related to some mutations or alterations in two genes, named TSC1 and TSC2. Discovered in 1997, TSC1 is located on chromosome 9q34 and produces a protein called hamartin. TSC2, discovered in 1993, is located on chromosome 16p13 and produces a protein called tuberin. The prevalence of the disease is 1/6000-10,000 live newborns, and it is estimated that there are 1-2 million sufferers worldwide. This paper presents a literature review and a family case report of a mother and two of her daughters with oral features of TS